The rasping Mouth of Death

I haven´t posted new stuff on the blog since quite some time, but not because I´m no more writing, but due to the amount of work which is going into some future blog articles. For that reason I was looking for something interesting I could post until the next bigger article is finished. I found a really interesting photo of the mouth of a sea lamprey (Petromyzon marinus) from the Zoological Museum at Kiel at my archive. It looks so wonderfully monstrous yet disturbingly aesthetic for its sheer obvious efficiency that I just had to share this:

Mouth of a sea lamprey (Petromyzon marinus), Zoological Museum Kiel

Sea lampreys are the largest lampreys and can reach lengths of over 1 meter, but usually stay within the range of 70-90 cm. The adult sea lampreys make living as parasites of larger fish, which they attack with their sucker-like mouths and keratinous pseudoteeth and tongue. They rasp and cut pieces out of the fish´s skin until they reach the underlying tissue, so they can suck the effluenting blood, lymph and shreds of tissue.

They became especially infamous after they invaded the Great Lakes and caused havoc among the populations of local fish like lake trouts (Salvelinus namaycush). Here is a taxidermy cast of a namaycush with an attached sea lamprey from Redpath Museum, Montreal:

Sea lamprey attacking a lake trout, Redpath Museum, Montreal.
Veröffentlicht unter Fische | 2 Kommentare

The weird little whales that hide within a cloud of their gut fluid

Many animals have developed amazing anti-predator adaptions, from mimicry to the ability to autotomize certain parts of their own bodies. One of the most bizarre defense mechanisms among mammals is found in the two exant members of the genus Kogia, the pygmy sperm whale (Kogia breviceps) and the dwarf sperm whale (Kogia sima). This dolphin-sized relatives of the enormous sperm whale (Physeter macrocephalus) evolved a method to confuse predators which is…well… special.

Pygmy sperm whale (Kogia breviceps) hiding in a cloud of rectal fluid © Markus Büher

Both pygmy and dwarf sperm whales are comparably slow and often bask motionless near the surface. This makes them an easy prey for predators like great white sharks or orcas, which were already found with Kogia remains in their stomaches. They were rarely and just very locally targeted by human hunting activities, for example off Japan, but their passive behavior on the surface made them also an easy target for whalers who could easily harpoon them from nearby boats. When harpooned, they were observed to emit a reddish-brown fluid from their anus which formed a cloud in the water. For this reason they are called Tsunabi in Japanese, a name that can be translated to something like „firecracker-whale“. Sometimes this fluid also leaks out of the anus of stranded specimens, what lead to their Sri Lankan name lie mulla, what means „blood dolphin“. The cloud formed by the dark fluid can apparantly be up to about 100 square meters in size.

This fluid is stored within an a unique sac-like bulging of the lower intestines which can hold up to about 12 l in large specimens of K. breviceps. The consistency of this reddish-brown fluid was compared with chocolate syrup (keep this in mind if you eat chocolate syrup for the next time…), but it can be also have a more granulous sand-like structure that dissolves in the water. Despite its location within the lower intestines it doesn´t seem to be just of fecal origin. It was already found in a foetal K. breviceps and a new-born and still un-nursed K. breviceps, what indicates that this substance which contains large amounts of carbon (up to more than 60%) is not just a digestion-by-product of their cephalopod-rich diet but is synthesized in the guts.

Pygmy sperm whale (Kogia breviceps) skeleton of a specimen found in the gulf of St. Lawrence. Centre d’interprétation des mammifères marins, Tadoussac. © Markus Büher

In one case a female K. sima and her calf were together with several dolphins accidentally caught in a net for tunas in the eastern tropical Pacific. The dwarf sperm whale emitted dark reddish fluid and tried to hide in the cloud whenever one of the dolphins approched it or the calf. This happened for several times, what also means that they usually don´t realease the full storage of intestinal fluid at once. This mechanisms, which appear to work in similar way as the inking of cephalopods, irritates the attackers optical and sensorical senses. This would also work in the dark waters at depths of 100 m and more where K. breviceps and K. sima usually hunt, because the olphactorical irritation would still work against sharks. I am not aware of any other depictions of the inking of Kogia, what also encouraged me to create an illustration of this bizarre behavior. Possibly it´s even the first published depiction, but I recently learnt that my good friend Julius Csotonyi also created somewhat earlier an illustration of this behavior for an upcoming book about cetaceans.

The reason why kogiids evolved this unusual defense mechanism is possibly linked to heavy predation, which could have an even more severe impact on their populations than we know from direct evidence. Pygmy and dwarf sperm whales have short life cycles and practice some sort of live-fast-die-young-way of life. They are sexually mature at 2,5-5 years, females have (unlike Physeter) a comparably large number of offspring during their lives and they ususally don´t live particularly long. This could also explain why they evolved such a special way to compensate their low speed and agility as a mean to escape from predators. Surprisingly, a similar behavior of releasing a cloud of „fluid“ was also recorded in Physeter as a response of stress, like approaching whalers or orcas. As they lack the sac-like bulge of Kogia to store a fluid, it´s likey that they really just release their feces however. This also indicates that this behavior have evolved already at comparably basal sperm whales.

Sources:

Ellis, Richard (2011). The Great Sperm Whale: A Natural History of the Ocean’s Most Magnificent and Mysterious Creature. Zoology. 179. USA: University Press of Kansas.

Plön S. The status and natural history of pygmy (Kogia breviceps) and dwarf (K. sima) sperm whales off southern Africa, PhD thesis. Grahamstown: Rhodes University; 2004.

Willis, P. M., and R. W. Baird. 1998. Status of the dwarf sperm whale, Kogia simus, with special reference to Canada. Can. Field-Nat. 112:114–125.

Veröffentlicht unter Blogposts in English, Säugetiere, Wale | 2 Kommentare

A tiny tusk within a broken tusk – just another narwhal oddity

The narwhal Monodon monoceros is almost a real-life fantasy creature. But not only due to its historical connection with the legendary unicorn – after all, a whale with an enormous tusk growing out of its head is much more fabulous than most legendary animals from ancient bestiaries which don’t even exist. If we would know narwhals only from fossils, we would surely deeply regret that we could never see this marvelous beast alive. But this creature – one of the most bizarre cetaceans which ever evolved – is an extant species and a good reminder that we still live alongside many incredible animals which can easily compete with the most extraordinary beasts of prehistoric times. There is a lot to say about narwhals, and it would be probably easy to write even a whole book only about their iconic tusks. I recently wrote about their rarely shown vestigial right tusks and a bizarre hybrid between a female narwhal and a male beluga.

Much about the exact function and use of the large torqued tusks still remains an enigma. Many assumptions about the functional use were based on examinations of the anatomy of the tusks, their surface, abrasions and wear patterns. Actual observations of active tusk usage are still extremely rare. A recent video shows that it has apparently really an assisting function for hunting however. But as usually only males possess fully developed tusks, it seems obvious that it has a role for sexual competition as well. Broken tusk tips found embedded into the skull bones of other males indicate that narwhals use their enormous teeth for physical interactions with other males as well.

One of the weirdest phenomena you can find within the cetacean literature are cases of broken narwhal tusk tips inside broken narwhal tusk tips. Errmmm…. What!? To avoid further confusion, I will show you some examples from which I took photos at the University of Copenhagen Zoological Museum.

University of Copenhagen Zoological Museum. Photo Markus Bühler

There are three of such tusks on display, however one of them is just a short fragment.

University of Copenhagen Zoological Museum. Photo Markus Bühler

There is a considerable part of the tips broken off, and you can see the cavity which was originally filled by the pulp. And within this cavity is a plug of torqued ivory, which perfectly fills the opened tusk.

University of Copenhagen Zoological Museum. Photo Markus Bühler

There are also longitudinal fractures and some bending of the tusk around the plug, and it looks like it was forcefully pierced into the broken end.

University of Copenhagen Zoological Museum. Photo Markus Bühler

So what happened here? Was there a narwhal with an already broken tusk tip seeking help by Dr. Monodon who used its own tusk in an altruistic attempt to fill the aching fracture with its own tusk and break the tip off? Or to stay more seriously, could it be that it happened by accident that a male narwhal rammed its thin tusk tip during an interaction in the already fractured tusk of an opponent? Or could it be that narwhal bulls touch each others tusks and one tip became by chance plugged into the opening of the fractured tusk?

University of Copenhagen Zoological Museum. Photo Markus Bühler

It really appears that something like this was happening, and the very existence of not just one but three such cases in a single museum could indicate some never observed behavior. However, as interesting as the idea of narwhal bulls accidentally practicing some sort of endodontic treatment to each others tusks appears, those broken tusks have a quite different background. It started with a tusk fracture, perhaps when a narwhal hunted fish on the sea bottom and had a traumatic collision with a rock. The tip of its tusk broke off, leading the whale quite likely in severe agony for some time. If something similar happens to a human, for example when an incisor is fractured and the pulp becomes exposed, it is just a matter of time until the pulpal tissue becomes infected by bacteria and necrotizes, at least if it is not properly treated. Under totally aseptic conditions – something only possible under laboratory conditions with totally germ-free mice or rats in an isolated environment – the exposed pulpal tissue can produce again new dentine at the fracture and seal the wound.

Fractured narwhal tusks can heal in a similar way without the usual necrotizing of the whole pulp and the resulting fatal conditions for the tusk. Perhaps this is due to the extreme size of the pulp and the many blood vessels within that lead to a better exchange of immune cells and lead also to a faster regeneration of the ruptured tissue. The seawater which always surround the wound might help as well. But admittedly, this is nothing but my personal speculation. It’s noteworthy that exposures of pulps in orcas – something quite common in captive specimens and those which specialize in hunting sharks and skates with highly abrasive skin – lead to necrosis of the pulps as well.

But narwhals can heal such fractures. When the cells at the outer area of the pulp-wound manage to produce a new formation of dentine the fracture is sealed. But this layer is apparently not tightly attached to the inner walls of the tusk. For this reason the ongoing apposition of reparative dentine forms over time a twisted plug which is pressed out of the pulp cavity, forming over time a tiny new tusk. And this is what appears to be the broken tip of a tusk rammed into the open pulp. The crack and bending of the fractured end were possibly also a postmortal artifact when the tusk dried.

I found the information about the reparative dentine of the broken narwhal tusks in the 2003 edition of Walker´s Marine Mammals of the World by Ronald M. Nowak. I was sadly not able to track down the original sources of Reeves, R.R., and S. Tracey.1980. Monodon monocers. Mammalian Species, no. 127, 7 pp and Newman, M.A. 1978. Narwhal. which was cited in Haley, D., ed. 1978. Marine mammals of eastern North Pacific and Arctic waters. Pacific Search Press, Seattle, 138-44. If anyone reading this has access to this original sources or any other information about this topic, I would be quite interested.

Veröffentlicht unter Anatomie, Blogposts in English, Teratologie, Wale | Schreib einen Kommentar

The bird that follows in the footsteps of the dinosaurs

Technically, all modern birds are dinosaurs, descendents of a lineage of theropods that evolved complex feathers and the ability to fly. But to be honest… most of them don´t really look very „saurian“ anymore. Those fancy feathers, toothless beaks and stumpy tails – usually coupled with a small overall size – just make it sometimes hard to accept their family background. Even if you know that filaments and feathers were in fact a quite common thing among dinosaurs, even if you are well aware of the fact that a lot of dinosaurs were of quite small body size and even if you are quite familiar with the evolutionary origins of modern birds you can still struggle to accept birds as real living dinosaurs. But sometimes you get a reminder about their theropod heritage, and a glimpse into a time when their ancestors were still not trying to conquer the airspace. For example if you take a close look at one of the largest extant birds, the emu Dromaius novaehollandiae. Don´t look at its pretty blue head or the shaggy double-feathers. Just look down at its staggering feet.

The foot of an emu. Photo by Markus Bühler

There is probably really nothing closer to a non avian theropod foot in the modern world. This is how people even today usually imagine a classical theropod foot. If you forget the rest of the body, you can really easily imagine that it belongs to something much more primordial, somethat that had still jaws lined with teeth, arms with big claws and a long tail. Of course there are some anatomical differences, for example the missing hallux of the emu. But it is still pretty awesome that something still walks the earth on such feet.

The ostrich has even bigger feet, but they are unique and utterly bizarre by nearly every standard, the feet of the cassowary are also pretty cool, but with their elongated claws still somehow too non-standard and not really that similar to any dinosaur feet. It it really frustrating that we missed some of the most spectacular birds that ever lived – the giant moas of New Zealand and the elephant birds of Madagascar – for just a few centuries. The feet of this giant birds were quite likely even closer to the feet of a medium-sized non-avian theropod than anything alive today.

I wrote some time ago about the incredibly polymorphous scales on the feet and legs of the ostrich. If we look at the feet of the emu, we can also see some quite interesting anatomical features as well.

Some of the scales on the backside of the tarsometatarsus form massive conical structures. I have to admit that I have no idea what function they have. But those cone-scales are surely something nobody would expect to have ever existed by looking at the bare bones of a fossil. I can´t help, but they could look pretty cool on the legs of a non-avian theropod as well.

The conical scales on the backside of an emu leg. Photo Markus Bühler

Should I ever get my hands on the foot of an emu, I will try to make a similar listing of its scale types and scale arrangements as I did for the ostrich. I can´t emphasize enough how important and helpful it is to look at the anatomy of living animals to reconstruct species which we know only from their bare bones. You will discover a lot of things which you possibly never noticed before, like in the case of the ostrich and emu those weird scale shapes, the volumous pads on the downside of the toes or the way in which the nails abrade. It will also remind you that we are still living in a world full of amazing animals, and that even many familiar species are much more fascinating and unusual than most people think.

Veröffentlicht unter Dinosaurier, Vögel | 1 Kommentar

Fishing for River Monsters in ancient Egypt

I recently visited the Royal Ontario Museum at Toronto, a monumental museum about zoology, paleontology, history, archeology and ethnology. Among the many wonderful objects in the exhibition about ancient Egypt, one artifact caught my eye in particular. It was a very large fishing hook with a massive leader of thick wire elements – all made of bronze.

Ancient Egyptian bronze hook with chain leader. Royal Ontario Museum, Toronto. Photo Markus Bühler

Here is another photo which shows the hook with some large bronze knifes and baskets to give you a better idea about its size. It was about the size of a hook for big-game-fishing in the sea, or for the largest freshwater fishes like big sturgeons or giant catfish. I have to admit I have a penchant for old and exotic fishing gear, and this one is really one of the coolest ones I have ever seen. From a technical aspect I really admire the work of the ancient smith who made it, the well thought-out construction which helped to avoid a twisting of the line which made it also possible to connect the comparably thin hook with a very strong line. The twisted eyes of the hook and the chain elements provided a maximum of durability. The shape of the hook is not just an U like the much simpler hook on the left, but is highly similar to modern hooks. The diameter in the middle of the curvature is especially thick and slightly flattened to withstand heavy loading. Whoever forged this some thousand years ago – he knew exactly what it needs to catch a monster fish.

Ancient Egyptian bronze hook with chain leader. Royal Ontario Museum, Toronto. Photo Markus Bühler

Today we find nearly identical constructions for shark hooks in which a massive swivel protects the line when the shark is spinning, and a short chain against the sharp shark teeth. Here is an example from the Deutsches Jagd-und Fischerei-Museum (Museum für hunting and fishing) at Munich, from a temporary special exhibition about sharks:

Shark hook with swivel, Deutsches Jagd-und Fischerei-Museum Munich

You can see an even more similar example of a historical shark hook which includes also a chain here.

The African continent is particularly poor in big freshwater fish, and only few species grow to sizes bigger than a meter. There is however one big exception, a fish which reaches enormous dimensions, the nile perch Lates niloticus. This behemoth can exceed lengths of 1,8 m and weights well over 100 kg, making it one of the heaviest freshwater fishes of the world. As usual there are a lot of anecdotes and hardly confirmable dates about much bigger specimens, what makes it quite hard to give more precise sizes and weights.

Nile perch from Lake Victoria, Uganda. Photo by smudger888. Note that this photo already includes a certain amount of forced perspective, and in direct comparison with the man behind it, the fish would appear arond 20-25% smaller.

Even before this species was introduced to many bodies of water in which it was originally not native (with desastrous effects, like in Lake Victoria) it had a very large range, which included the nile in North Africa. The ancient Egyptians were well familiar with this fish, and there are even cases known of mummified nile perches, like this specimen in the Egyptian Museum at Cairo. Fish was caught with nets, harpoons and also hook and line (which included simple rods but also handlines), and it was an important source of protein. Most of those fish were however comparably small, species like cyprinids, tilapias or smaller and medium sized catfishes. Catching the really big nile perches was probably not that easy as it required special gear. The fabrication of this hook was probably already a lot of work and bronze was still very valuable even at small amounts at that time.

Fish relief, about 2.500 years BC, Kunst-und Gewerbemuseum Hamburg

Bones of large nile perches were also found among other animal relics at archeological sites, sometimes in form of waste, sometimes as burial objects. Some of them include relics of really huge specimens, like several nile perches from the necropolis of Elephantine which were about 1,8 m in life. One particular specimen was even about 1,9 m. There were also a lot of nile perch bones found at the temple of Satis, which included several very large specimens, including one of about 1,9 m. It´s noteworthy that this is still not bigger than the largest modern day nile perches from the big lakes in their more southern range. Today such huge specimens are no more found at Egypt anymore, but it seems that they were considerably more common in the past, and the ancient fisherman obviously managed to catch them.

As nile perches usually prefer comparably deep water, they were likely rarely caught with harpoons, and it seems likely that they were also no common targets for neting, at least not the big ones. So angling with hook and line in big game style was likely the most efficient way to target particularly big specimens, which had also surely a considerable worth. The ancient Egyptians called the nile perch „the fighter“, what also possibly indicates its behavior when it was caught with hook and line. Those fishermen had nothing even remotely comparably to the modern fibreglas rods and reels, but just handlines to catch those enormous fish which could weigh considerably more than an average human.

If you want to learn more about fishes and fishing in ancient Egyptian art and culture, take a look at those links: 1, 2, 3.

Sources:

BOESSNECK, J. und von den DRIESCH, A. (1982): Studien an subfossilen Tierknochen aus Ägypten. – Münchener Ägyptol. Studien, 40:58, München-Berlin.

Veröffentlicht unter Archeology, Curiosity of the Day, Fische, Megafische | Schreib einen Kommentar

How Vanuatuan boars grow circle tusks that impale their own jaws

I wrote some time ago about zoological treasures in archeological, ethnological and historical museums. Today I want to share some quite interesting examples of such „treasures“ which I have seen in the Oceania exhibition of the Ethnological Museum of Berlin. What you see here is a boar’s mandible from Vanuatu, a group of islands located in the South Pacific Ocean east of Australia.

Boar mandible with circle tusks from Ambae, Vanuatu. Ethnological Museum of Berlin, photo Markus Bühler

The obviously most striking feature of the mandible are the extremely long circular tusks. They are so long that their tips have grown into the lower jaw and penetrated the bone.

Boar mandible with ingrown lower tusks. Ethnological Museum of Berlin. Photo Markus Bühler


You can see how how the infection caused by the tusk tips lead to a degradation of the surrounding bone and a thickening of the bone behind. The ingrown tusks acts like foreign bodies and cause a constant local infection. In the living animal they must have pierced the cheeks as well.

Boar mandible with ingrown lower tusks. Ethnological Museum of Berlin. Photo Markus Bühler

This is an extracted lower boar tusk, which shows how the tooth formed a full circle, with the tip just next to its own apical end.

Extracted circle tusk. Ethnological Museum of Berlin. Photo Markus Bühler

Here is another example, but this boar luckily died before the tusks could impale its jaw.

Boar mandible with still not fully formed circle tusks. Ethnological Museum of Berlin. Photo Markus Bühler

For a considerable time I was wondering how this circle tusks could grow to such grotesque shapes. It was obvious that it resulted from a lack of abrasion with the upper tusk, which usually limit the lengths of the lower tusks while forming constantly sharp edges. Sometimes we see similar cases as a result of misplaced teeth which lead to a missing abrasion between upper and lower tusks. I covered such a case of a pot-bellied pig which had highly elongated lower tusks. The extremely shortened skull and jaws of pot-bellied pigs often result into various tooth displacements. But those jaws from Vanuatu belonged to pigs which were still quite primitive compared with most modern breeds, with long heads similar to wild boars and with well grown teeth.


So how could they grow this bizarre circle tusks? Were those pigs possibly selected for dental misplacement that make such teeth growing“naturally“? The answer is no, those boars were actually results of a surgical procedure which made their tusks growing into this unnatural shapes. Their upper tusks were extracted at early age, so the natural curve of the lower tusks could grow longer and longer without being abraded by an antagonistic upper tusk. The boars selected for this were kept isolated and fed with special food, and apparently they were also castrated. This was likely to avoid accidental fractures of the tusks during fights with other boars and to let them grow better even with the chronic inflammation of the cheeks and jawbone.


But why did Vanuatuans want boars with circle tusks? The answer is pretty simple, because breeding boars with circle tusks was literally like breeding money. Those circle tusks were not just used for decoration or jewelry but as money as well. And they longer they were, the bigger their worth was. They were used to make jewelry like necklaces, as decoration for sculptures and for certain rituals. You have to keep in mind that it takes several years until a boar has grown a circle tusk, and even more for a spiral tusk. During this whole time it needs extra food, and even more than a normal pig, which can also forage in the wild. But when the boar is finally killed and its tusks removed, they are worth a little fortune. I highly recommend to watch this short documentary about the role of circle tusks in modern Vanuatu. You can also see a living boar with circle tusks which pierce its cheeks. There are also a few incredibly extreme spiraling tusks from an ethnological collection featured as well.


You can get an idea about the importance of circle boar tusks if you take a look at the flag and the coat of arms of Vanuatu.

Flag and coat of arms of Vanuatu. Source Wikipedia

The whole museum exhibition at Berlin was moved to another location after my last visit and I don’t know if those specimens will be still exhibited in the new museum. It was the same exhibition which also included the mislabeled Kogia mandible about which I already wrote.

This is mainly an updated version of a blog post which I already wrote in 2009 in German. You can find the original post here.

Veröffentlicht unter Anatomie, Blogposts in English, Museen, Säugetiere, Teratologie | 2 Kommentare

Ein bizarrer Hybride aus Narwal und Beluga – wie ich den merkwürdigsten Wal der Welt rekonstruierte

Lebendrekonstruktion des Narwal x Beluga-Hybriden

Kürzliche erregten neue Forschungsergebnisse um einen bizarren Hybriden aus Narwal (Monodon monoceros) und Beluga (Delphinapterus leucas) weltweite Aufmerksamkeit. Er wurde nach Angaben eines grönländischen Inuit namens Jens Larsen 1986 oder 1987 in der Disko-Bucht im Westen Grönlands geschossen, und wies unter anderem einige äußerst ungewöhnliche Besonderheiten der Zähne auf. Der Wal soll grau gefärbt gewesen sein, und seine Brustflossen denen eines Belugas, die Schwanzflosse dagegen eher der eines Narwals geähnelt haben. Larsen beschloss aufgrund des ungewöhnlichen Aussehens des Wals dessen Schädel aufzuheben. Etwa zur gleichen Zeit sollen in der Gegend noch zwei ähnliche Exemplare geschossen worden sein, von denen jedoch eines versank und nicht geborgen werden konnte. Der Kopf des dritten Exemplars wurde zum Skelettieren an der Küste ausgelegt, allerdings niemals wiedergefunden, so dass als einziges physisches Relikt der von Larsen aufbewahrte Schädel verblieb.

Als 1990 der dänische Zoologe und Walexperte Mads Peter Heide-Jørgensen den Schädel auf dem Dach eines Werkzeugschuppens im grönländischen Kitsissuarsuit entdeckte, erkannte er gleich dass es sich dabei um etwas wirklich außergewöhnliches handelte. Larsen stiftete den Schädel für weitere Untersuchungen, woraufhin dieser nach Kopenhagen gebracht wurde. Seine Anatomie zeigte Ähnlichkeiten zu jener von Narwalen und Belugas, wies aber auch eine Reihe von Merkmalen auf, die völlig einzigartig waren, und sich von allen anderen bekannten Walen unterschieden. Anhand der teilweise verwachsenen Suturen (Knochennähte) von Oberkiefer und Zwischenkiefer lies sich erkennen dass es sich um ein erwachsenes und bereits älteres Tier gehandelt hatte. Beim Vergleich mit den Schädeln von Belugas und Narwalen  lag der Schädel in seinen Proportion etwa zwischen beiden Arten, in seinen Größendimensionen allerdings etwas über deren durchschnittlicher Größen. Bereits vor einigen Jahren wurde für den Hybriden der Begriff „Narluga“ geprägt, welchen ich hier auch verwenden möchte.

Schädel des Narlugas. Foto Mikkel H. Post, Zoologisches Museum Kopenhagen

Besonders ungewöhnlich waren allerdings die Zähne, welche sich sowohl in Anzahl, Form als auch Größe von jenen von Belugas und Narwalen unterschieden. Belugas besitzen im Ober-und Unterkiefer je 8-11 Zähne auf jeder Seite.

Belugaschädel im Zoologischen Museum Kiel. Foto Markus Bühler

Die Zähne von Belugas sind zapfenförmig, und nutzen sich vor allem im Oberkiefer oft auf typische Weise löffelförmig ab.

Nahansicht der Beluga-Zähne mit den unterschiedlichen Abrasionsformen in Ober-und Unterkiefer. Foto Markus Bühler

Beim Narwal dagegen besitzen üblicherweise nur die Männchen einen einzigen funktionellen Zahn, bei welchem es sich um einen massiv modifizierten linken oberen Eckzahn (er entstammt dem Oberkiefer und nicht dem Zwischenkieferknochen, ist also kein Schneidezahn) handelt, welcher außerhalb des Mauls durch die Haut der Oberlippe wächst.

Narwalschädel im Staatlichen Museum für Naturkunde Stuttgart. Foto Markus Bühler

Normalerweise ist er nur auf einer Seite ausgeprägt, während der deutlich kleinere und auch nicht gedrehte rechte Eckzahn üblicherweise im Kieferknochen verbleibt. Bei weiblichen Narwalen finden sich derartige im Kiefer verbleibenden Eckzähne sowohl rechts als auch links.

Nicht durchgebrochener rechter Eckzahn eines Narwals, Kunstkammer im Landesmuseum Württemberg im Alten Schloss Stuttgart. Foto Markus Bühler

Eine derartig extrem ausgeprägte dentale Asymmetrie wie bei Narwalen ist einzigartig unter den lebenden Säugetieren. Gelegentlich finden sich allerdings auch Exemplare mit einem auch rechts teilweise oder sogar voll  ausgebildeten Stoßzahn, oder auch Weibchen mit ein oder sogar zwei Stoßzähnen. Das eigentliche Maulinnere ist dagegen völlig zahnlos. Gelegentlich finden sich auch kleine verkümmerte Zähne an der Basis des Stoßzahns im Knochen des Oberkiefers, welche allerdings nicht durchbrechen.

Der Schädel des Wals aus der Diskobucht hatte dagegen ursprünglich im Oberkiefer auf jeder Seite je 5 und im Unterkiefer je 4 Zähne, von denen allerdings ein oberer und ein unterer postmortal verloren gingen. Aufgrund von Abrasionen und ihrer Position im Knochen kann man davon ausgehen dass sechs oder sieben der zehn Oberkieferzähne zu Lebzeiten in die Mundhöhle ragten.

Ansicht des Oberkiefers von der Gaumenseite mit erkennbaren Bereichen der im Knochen verbliebenen vordersten Zähne. Foto Markus Bühler

Die drei oder vier vordersten Zähne lagen horizontal im Knochen und sind nie in die Mundhöhle durchgebrochen. Ihre sehr langgestreckte gerade Form erinnert etwas an die nicht durchbrechenden Stoßzähne von Narwalen, die für diese typische Verdickung an der Wurzelspitze fehlt allerdings. Die vorderen Zähne ließen sich nicht ohne Beschädigung des umliegenden Knochens entfernen, anhand von Röntgenaufnahmen ließ sich ihre Form und Länge aber ermitteln. Dies ergab eine stattliche Länge von 25,6 cm für den linken ersten Oberkieferzahn und 24,8 cm für den rechten ersten Oberkieferzahn. Die zweiten hatten immerhin noch eine Länge von 19,6 cm und 21,5 cm, während die weiter hinten liegenden immer weiter an Länge abnahmen, dafür aber auch eine mehr oder weniger starke Krümmung aufwiesen. Nach Angaben von Jens Larsen hatte der Narluga welcher im Wasser verloren gegangen war, auch sichtbare vordere Zähne im Oberkiefer.

Einige der aus dem Kiefer entfernten Zähne. Foto Eline Lorenzen, Zoologisches Museum Kopenhagen

Die Zähne im Unterkiefer zeigten ebenfalls eine Reihe von Besonderheiten. Zunächst waren sie ausgesprochen groß und massiv gebaut, deutlich größer als die Zähne von Belugas. Auch der gesamte vordere Bereich des Unterkiefers war äußerst breit und massiv. Aufgrund ihrer Form und Größe müssen die unteren Zähne sogar noch bei geschlossenem Maul teilweise sichtbar gewesen sein. Einige waren merkwürdig verdreht und zeigten vage Andeutungen von Längsrillen, vergleichbar den Stoßzähnen von Narwalen. Die ungleichmäßigen Abrasionsmuster ließen ebenfalls erkennen dass sie sich während des Wachstums leicht um die eigene Achse gedreht haben müssen.

Nahansicht der Zähne im rechten Unterkiefer. Foto Markus Bühler

Die vier rechten und ersten drei linken Unterkieferzähne standen alle recht dicht beieinander, waren von ähnlicher Größe und waren deutlich noch vorne geneigt. Der leider nicht mehr vorhandene vierte linke Zahn saß dabei aber deutlich weiter hinten im Kiefer als sein Pendant auf der rechten Seite, zudem konnte man anhand des leeren Zahnfachs erkennen dass er nicht nur deutlich kleiner gewesen sein muss, sondern auch sichtlich nach hinten geneigt war.

Ansicht der linken Unterkieferhälfte. Man erkennt das leere Zahnfach des deutlich kleineren und weiter hinten liegenden letzten Zahns sowie weiter unten den Austritt des Nervus mentalis aus dem Foramen mentale. Foto Markus Bühler

Als der Schädel erstmals untersucht wurde, war seine genaue Identität noch nicht abschließend geklärt. Ursprünglich wurde auch ein Narwal mit starken dentalen Anomalien für möglich gehalten, die Möglichkeit eines Hybriden allerdings auch schon in Betracht gezogen. Kürzlich vorgenommene Untersuchungen seines Erbgutes durch eine Forschergruppe um Eline Lorenzen vom Zoologischen Museum Kopenhagen konnten nun tatsächlich die Vermutung um seine hybride Herkunft bestätigten. Zudem konnte ermittelt werden dass es sich bei diesem wirklich ungewöhnlichen Exemplar um eine Kreuzung aus einem weiblichen Narwal und einem männlichen Beluga handelte. Die Beschreibung der beiden anderen mutmaßlichen Hybriden durch Jens Larsen ist auch insofern bemerkenswert weil sich hierbei die Frage stellt ob diese alle unabhängig voneinander gezeugt wurden, oder ob sie möglicherweise alle die selbe Mutter oder den selben Vater hatten. Ohne verbliebene körperliche Relikte dieser beiden Exemplare wird sich diese Frage allerdings nie beantworten lassen. In der Diskobucht kommen sowohl Narwale als auch Belugas vor, und sie ist auch eine der wenigen Gegenden in welcher beide Arten auch zu ihrer jeweils unterschiedlichen Paarungszeit anzutreffen sind. Gelegentlich schließen sich einzelne Belugas auch Gruppen von Narwalen an, aber auch einzelne Narwale in Belugaschulen kommen gelegentlich vor, etwa ein junges und möglicherweise verirrtes Narwalmännchen welches sich im kanadischen Sankt-Lorenz-Strom den dort lebenden Belugas angeschlossen hat. Es gibt eine ganze Reihe von dokumentierten Hybriden zwischen verschiedenen Walspezies, sowohl unter Zahnwalen wie Delfinen oder Schweinswalen, als auch von Bartenwalen.

Die Interaktion der unterschiedlichen Erbanlagen ist wirklich erstaunlich. Besonders dahingehend dass jene Gene welche beim Narwal das Größenwachstum und die Torsion des Stoßzahns steuern sich in stärkeren Maße auf die Zähne des Unterkiefers ausgewirkt haben als auf jene im Oberkiefer. Es wäre sehr interessant zu wissen ob, und falls ja wie, sich bei der umgekehrten Kreuzung zwischen einem Narwalmännchen und einem Belugaweibchen die Genkombinationen anders ausgewirkt hätten.

Vergleich der Schädel von Narwal (a), Narluga (b) und Beluga (c). Mikkel Høegh Post, Zoologisches Museum Kopenhagen

Eine weitere erstaunliche Erkenntnis ergab die Untersuchung der Kohlenstoff-und Stickstoffisotpe im Kollagen des Knochens. Demnach ernährte sich der Narluga nicht von den gleichen Beutetieren wie Belugas oder Narwale, sondern erbeutete vor allem Fische in tieferen Wasserschichten. Möglicherweise bevorzugte er aufgrund seiner ungewöhnlichen Bezahnung bestimmte Beute die er nur in tieferen Wasserschichten finden konnte.

Seit ich 2007 zum ersten  Mal von diesem bizarren Wal gelesen habe, war ich fasziniert von ihm. Da die ursprüngliche Veröffentlichung von Mads Peter Heide-Jørgensen damals noch nicht im Internet frei verfügbar war, schrieb ich ihn an und bekam freundlicherweise eine digitale Version von ihm zugesendet. Die gescannte Version des Drucks beinhaltete eine ganze Reihe von interessanten Fotos, allerdings leider in sehr unzufriedenstellender Bildqualität. Zudem gab es einige weitere Fotos des Schädels im Internet, viele seiner Details ließen sich aber auch bei ihnen nicht vollends erkennen. Ein Jahrzehnt später, im Frühsommer 2017, bekam ich die Möglichkeit den Narlugaschädel im Original im Archiv des Zoologischen Museums in Kopenhagen zu begutachten, und seine Anatomie vor Ort zu studieren. An dieser Stelle möchte ich mich noch einmal ganz herzlich bei Eline Lorenzen und auch vor allem bei Daniel Klingberg-Johanson dafür bedanken den Schädel und viele andere faszinierende Stücke im nichtöffentlichen Archiv des Museums ansehen zu können.

Schädel des Narluga im Archiv des Zoologischen Museums Kopenhagen. Foto Markus Bühler

Was mich ganz besonders interessierte, war wie dieser Wal wohl zu Lebzeiten ausgesehen haben könnte. Da lediglich der isolierte Schädel, die Verwandtschaftsverhältnisse und die sehr vage Beschreibung von Jens Larsen vorhanden waren, stellte sich hier eine Aufgabe,welche viel eher der Rekonstruktion eines nur von Fossilien bekannten ausgestorbenen Tieres vergleichbar war (etwa meiner Basilosaurus-Rekonstruktion). Bisher gab es keinerlei Bilder welche einen Eindruck vermittelten wie der Hybrid einmal ausgesehen haben könnte (es gab eine einzige Darstellung, welche allerdings lediglich eine digitale Kombination aus einem Narwal und einem Beluga darstellte, und weder die Zähne noch die beschriebene Farbe berücksichtigte), was seine Rekonstruktion umso interessanter machte.

Da das einzigartige Gebiss das hervorstechendste Merkmal des Narlugas war, sollte es bei der Rekonstruktion auch entsprechend gut erkennbar sein. Daher entschloss ich mich direkt ein Bild des komplett artikulierten Schädels aus einer vor längeren Zeit erfolgten Pressemitteilung als Basis zu verwenden. Bei Zahnwalen im Allgemeinen und bei Gründelwalen wie dem Narwal und Beluga im Speziellen wird der Schädel von einer großen Menge Weichgewebe umschlossen. Vor allem die Melone, das Echolotorgan welches oberhalb des Schädels sitzt, nimmt einen sehr großen Raum ein. Dazu kommen noch die Bereiche in denen die komplexen Strukturen zum Blasloch führen, sowie die Lippen und natürlich das dicke Unterhautfettgewebe. Eine sehr hilfreiche Illustration zum besseren Verständnis der Anatomie eines Belugakopfes kann man hier sehen.

Rekonstruktion der Kopfform des Narlugas anhand des Schädels

Bei Belugas kommt noch hinzu dass sie durch Muskelkontraktion die Form ihrer Melone in gewissem Rahmen verändern können, was das Heranziehen von Referenzbildern noch problematischer machte, denn selbst bei ein und demselben Individuum kann auf verschiedenen Bildern die Melone unterschiedlich geformt sein. Belugas besitzen auch für Wale ungewöhnlich gut ausgebildete und bewegliche Lippen. Das alles musste bedacht werden, selbst wenn hier selbstverständlich einiges an künstlerischer Freiheit einfloss. In seiner Kopfform steht der Narluga nun zwischen jenen der beiden Elternarten, mit den eher stärker verrundeten Formen des Narwals aber einer schlankeren Halspartie und etwas voluminöseren Oberlippen um dem Belugaerbe gerecht zu werden. Den fehlenden letzten Zahn auf der linken Unterkieferseite rekonstruierte ich anhand der Größe und Ausrichtung des leeren Zahnfachs im Kiefer. Man sieht nun ganz gut die starke Asymmetrie in der Position und Form der Zähne im Unterkiefer. Bei der Pigmentierung des Maulinneren verwendete ich das Foto eines Narwalmauls als Referenz. Bei Walen findet sich nicht wie sonst bei Säugern üblich eine klare Abgrenzung zwischen dem normalerweise von Schleimhaut ausgekleideten Maulinneren und den von Epidermis bedeckten Lippen.

Narlugakopf mit rekonstruiertem vierten linken Zahn im Unterkiefer

Bei der Körperform stützte ich mich auf die skelettalen Proportionen von Belugas, um anhand des Schädels die dazugehörigen Dimensionen des Körpers festzulegen. Auch hier versuchte ich einen Mittelweg zwischen den zwei Elternarten zu finden. Bei Narwalen ist der Körper sehr stromlinienförmig und glatt, während Belugas einen sehr stark vom Körper abgesetzten Kopf und seitlich am Körper liegende Fettpolster und Längsfalten besitzen. Auch haben sie noch einen wahrnehmbaren, leicht eckigen Rückenkiel, während bei Narwalen die Rückenflosse bis auf eine Linie von kleinen, kaum erkennbaren Hauttuberkeln zurückgebildet ist. Belugas haben größere und deutlich breitere Brustflossen als Narwale, weshalb ich sie aufgrund der Beschreibung Larsens auch als Referenz verwendete. Bei der Schwanzflosse dagegen orientierte ich mich an den stark halbkreisförmig ausgebildeten Flossenlappen des männlichen Narwals. Interessanterweise findet sich bei Narwalen ein Geschlechtsdimorphismus bei der Form der Schwanzflosse, welche allem Anschein nach mit den hydrodynamischen Auswirkungen des Stoßzahns zusammenhängt.

Die Farbe des Narluga wurde als grau beschrieben, und unterscheidet sich insofern deutlich von der weißen, beziehungsweise weiß-schwarz marmorierten Farbe von Belugas und Narwalen. Allerdings sind bei beiden Arten die Jungtiere noch grau gefärbt, und es ist nicht völlig ausgeschlossen dass bei dem Hybriden möglicherweise atavistische Anlagen zum Vorschein kamen, welche aus der Zeit stammten, als ihre Vorfahren noch nicht in polaren Gebieten lebten, und vermutlich auch noch nicht von weißer Grundfarbe waren. Daher bekam der Narluga ein Farbschema welches sich an den Jungtieren der beiden Elternarten orientierte. Im Kopf-und Halsbereich deutete ich eine leichte graue Marmorierung an, welche mehr einem jungen Narwal entspricht, der hintere Körperbereich dagegen der homogeneren Farbe junger Belugas. Zudem nahm ich mir die kreative Freiheit die Brustflossen etwas dunkler vom Körper abzusetzen, wie es in stärkerer Form bei Narwalen der Fall ist.

Narluga mit hypothetischen Farbschema

Um den Hintergrund noch ein bisschen interessanter zu gestalten fügte ich einen kleinen Schwarm Polardorsche (Boreogadus saida) ein, eine Fischart welche auch in der Disko-Bucht lebt, und sowohl vor Flussmündungen bis hinab in Tiefen von 900 m vorkommt. Diese Fische stellen auch eine wichtige Nahrung für Belugas und vor allem Narwale dar.

Polardorsche (Boreogadus saida)

Insgesamt arbeitete ich an der Rekonstruktion mehrere Monate, und trotz mancher Ungewissheiten und künstlerischer Freiheiten bestimmter Details hoffe ich doch sehr dass sie zumindest einen realistischen Eindruck dieses außergewöhnlichen Wals vermitteln kann.

Quellen:

Fontanella, J. E., Fish, F. E., Rybczynski, N., Nweeia, M. T. and Ketten, D. R.
(2011). Three-dimensional geometry of the narwhal (Monodon monoceros) flukes in relation to hydrodynamics. Mar. Mamm. Sci. 27, 889-898.

Heide-Jørgensen, M. P. & Reeves, R. R. Description of an anomalous Monodontid skull from west Greenland: A possible hybrid? Mar. Mamm. Sci.9, 258–268 (1993).

Nweeia, M.T., et al. 2009. Considerations of anatomy, morphology, evolution, and function for narwhal dentition. The Anatomical Record 295, 6: 1006-1016.

M. Skovrind et al. Hybridization between two high Arctic cetaceans confirmed by genomic analysis. Scientific Reports. Vol. 9, June 20, 2019. doi:10.1038/s41598-019-44038-0.

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A bizarre narwhal x beluga hybrid from Greenland – how I reconstructed the weirdest whale of the world

There are awesome news about one of the most unusual cetaceans in modern history, an enigmatic hybrid between a narwhal (Monodon monoceros) and a beluga whale (Delphinapterus leucas).

The specimen was shot at Disko Bay, Greenland, in 1986 or 1987 and the skull – the only remaining relic – collected there in 1990 and sent to Copenhagen. I´ve been fascinated by this freak of nature since I´ve read about it for the first time in 2007. From all the photos available at that time I tried to make a reconstruction of it, but I was not really happy with it. In 2017 I had finally the chance to examine the original skull of this specimen in the archives of the Zoological Museum at Copenhagen, what gave me some highly worthy insights into its extremely weird anatomy. Besides the skull only a few vague descriptions of the living animal were known, so dealing with it was like dealing with the remains of a prehistoric animal only known from fossils. This made it of course even more interesting to make a reconstruction of the living whale, which was subsequently termed „narluga“ by some people.

I want to thank here Eline Lorenzen and especially Daniel Klingberg-Johansson for the chance to visit the non-public archive where the skull is located. The public exhibition of the Museum has many incredible and absolutely priceless specimens (more about some of them in a future blogpost), but as usual a lot of the really good stuff is in the archives. Thanks again Daniel for this awesome tour to the museal catacombs!

In this blogpost I want to give you some more background information which is known about the narluga, and how I tried to give the skull a face and a body. As I already wrote it was shot in 1986 or 1987, by an inuit hunter named Jens Larsen. The correct date is not known, as Larsen who didn´t remember the year for sure. It was discovered by Mads Peter Heide-Jørgensen on the roof of a toolshed at Kitsissuarsuit, which is located at the mouth of Disko Bay, West Greenland. Larsen had perceived it unusual enough to save the skull and donated it for further examination. He sadly could not give much more information about it, unless that it had flippers which resembled those of a beluga and a fluke more similar to those of a narwhal, but a coloration which was not white like a beluga or white and dark-gray mottled like a beluga but uniformlys gray and unlike those of those two species. What was even more interesting was the fact that he remembered that there were two additional specimens, which were shot as well. One was lost during the hunt (modern inuit shot belugas and narwhals usually with guns, so a lot of them just sink to the bottom of the sea and are lost), the head of the other one was saved and left near the water for maceration, but never retrieved.

Articulated skull of the Narluga, Mikkel H. Post, Natural History Museum of Denmark

After the skull was sent to Copenhagen, it was examined and compared to various skulls of belugas and narwhals from the collection of the Zoological Museum. It exhibited several unusual features. It was somewhat larger and more elongated than the means of the skulls used for comparison. Its sutures of the premaxilla/maxillare were fused, what indicated that the specimen was already comparably old. The most bizarre feature of it was however the dentition. It was totally unlike any other known whale.

Narluga maxillary dentition, photo Markus Bühler

It had originally ten upper and eight lower teeth, from which one of the maxillary teeth was already lost when the skull was found. In the living narluga, six or seven of the upper teeth were likely exposed inside the cavity of the mouth, as they showed also signs of abrasion. The three most anterior teeth however apparantly never erupted through the gums and remained mainly within the bone. Their appearance was extremely strange, very thin, long and horizontally orientated within the bone, a bit similar to the unerupted vestigal teeth of narwhals but lacking their typical knog at the apical end. The more distal teeth were shorter and more curved. According to Lars Jensen, the specimen which sank and was lost had even some visible protruding upper teeth.

Extracted teeth, photo Eline Lorenzen, Natural History Museum of Denmark

The mandibular teeth in contrast were all eruted, very large and massive, assymetrical in shape and orientation. In the living animal they were likely visible even when the narluga had its mouth closed. Two of those teeth show unusual curving and slight twisting which must have occured during growth, and even longitudinal grooves vaguely similar to those seen in erupted narwhal tusks.

Right mandibular teeth, photo Markus Bühler

The most distal tooth on the left side was very small and much more posteriorly located then the fourth tooth on the right side. It was sadly lost, but the orientation of the tooth socket indicates quite clearly that it was pointing backwards.

Narluga skull, photo Markus Bühler

At the time of its first examination it was still not known if it really was a hybrid between a narwhal and a beluga, or just a really unusual narwhal with extreme dental anomalies. Genetic examinations however clearly showed that it really was a male hybrid, with a narwhal mother and a beluga father. Another really interesting result from the examination of carbon and nitrogen from the bone collagen revealed that the narluga differed in diet from both belugas and narwhals. The fish on which it preyed were apparantly from more benthic regions than those usually consumed by narwhals and belugas. Perhaps this diet resulted from the unique dentition of this individual, which made it harder to hunt and catch the more common prey animals of its parental species.

When I worked on the reconstruction of the living animal, I tried to take everything known about it into account. The shape of the skull, the orientation and abrasions of the teeth and the description of the external features like flippers, fluke and coloration, as well as the anatomy and life appearance of Monodon and Delphinapterus. I gave the narluga the head-to-body-ratio of a beluga and tried to make its external body shape intermediate between those of a narwhale and a beluga. Narwhals have streamlined bodies, but belugas have a very distinct neck area and weird fat deposits at their belly area.

Narluga reconstruction

By far the most difficult part of the reconstruction was the head and mouth. Narwhals and belugas differ in several aspects of their cranial soft tissue. Belugas have – quite unusual for extant cetaceans – quite fleshy and flexible lips, which can be moved into a lot of shapes. Even more problematic was their ability to change the shape of their melon area, because this made it really hard to find a good reference with which I was happy, since every beluga photo looks different – even if it´s the same indivudual but with different melon shapes. I made many tries until I found something with which I was mainly happy and still somewhat intermediate between narwhals and belugas. I didn´t gave it beluga lips, but made them at least a big more pronounced than those of narwhals.

Narluga head reconstruction (still without the fourth left mandibular tooth)

The upper teeth are not visible here (they usually never are visible from lateral views in most odontocetes). I directly used the original shape of the lower teeth of the articulated skull from an earlier press release to get them as correct as possible and to show also such features like the partial torquing and spiraling. The fourth left tooth was missing, so I had to reconstruct it from the position and size of its tooth socket, which show that it was much smaller than the other mandibular teeth, assymetrically distally located and backwards-pointing.

Reconstruction of the missing fourth left mandibular tooth. You can see the very strong assymetrical location

I nearly missed to portray a minor but important detail until the very end, the blowhole which is nearly invisible as this position. But luckily I just remebered to draw it before I sent the final version to Eline Lorenzen.

The coloration was described as gray and unlike those of narwhals or belugas. This is not that unusual that hybrids don´t just show intermediate patterns or colors of their parental species but unique new traits. Because both belugas and narwhals are comparably uniformly gray at young age, I used them as reference for the color of the narluga, with a very slight mottling reminiscent to those of juvenile narwhals. Because it was an older specimen, I gave it a few scars, because it is very likely that it received some from rocks and ice during its life.

To make the scenery a little bit more atmospheric I added a small swarm of polar cods (Boreogadus saida) in the background. This species occurs in the area where the narluga was shot, from river mouths to depths up to 900 m, what makes it a very well fitting faunal element, especially as it´s a very common food item for both belugas and narwhals.

Polar cods (Boreogadus saida)

I made the flippers mainly based on the large pectoral fins of belugas, but somewhat lesser developed, but slightly darker than the rest of the body as seen in narwhals. The fluke shows the unusual „backwards“ shape of male narwhals (those of females look more normal), just somewhat lesser expressed. Like all my other digital art projects (for example my recent Basilosaurs), this was made with GIMP. The whole project took several months until it was finally finished, but it was also a really interesting and exciting project. A lot of it was surely speculative, even if based on some known known facts. Perhaps anytime we will see another, perhaps even living narluga, which will show how close my rendition was to the true life appearance.

Sources:

Heide-Jørgensen, M. P. & Reeves, R. R. Description of an anomalous Monodontid skull from west Greenland: A possible hybrid? Mar. Mamm. Sci.9, 258–268 (1993).

Mikkel Skovrind et al. Hybridization between two high Arctic cetaceans confirmed by genomic analysis, Scientific Reports (2019).

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Into the forest – filming a nature documentary about European reptiles and amphibians

Last year I was involved into a fantastic project, the production of the wildlife documentary „Into the Forest: Reptiles & Amphibians“ by my good friend Bryan Maltais.He made already several other shorter documentaries, including the award-winning production „Metamorphosis“ about the amphibian life in a wetland in Colorado. But this was by far his biggest project. I want to write here about the filming and the background of „Into the Forest“, which is now also available on Amazon Prime, both in English and German.

German version (this link only works in DE)

English version (link only works in USA)

You can see the trailere here:

Bryan spent his early youth with his German mother and American father in Germany but later grew up in the U.S. Over the decades he regularly came back to visit his second home and the German part of his family. During those vacations he regularly visited a forest near Denkendorf, a village not far away from Stuttgart, in the southwest of Germany. It was this forest where he came for the first time into contact with the European herpetofauna and other native animals. He later studied wildlife biology and developed a particular interest into reptiles and amphibians. Over the years Bryan became a professional nature and landscape photographer and produced several documentaries, mainly about reptiles and amphibians.

Bryan Maltais at Mills Lake inside Rocky Mountain National Park

We met for the first time in 2014 after I discovered his documentaries on YouTube and realized that Denkendorf is in fact comparably close to my own place of residence. Over the years we met for several more times for herping tours and I introduced Bryan to various other interesting locations like the habitat of my local green lizard (Lacerta viridis) population or the Black Forest with its melanistic European adders (Vipera berus).

Bryan taking close-up photos of a green lizard

But „Into the Forest“ became a much bigger and much more extensive project than just a few tours to the woods. Bryan spent three whole months in Germany to document the rise of nature from the last snow of march to the early summer in june. He was filming for nearly every single day and sometimes even during night, and when he wasn’t filming he worked on editing and cutting the videos.

To produce a high quality documentary he used a 4k camera so you can also enjoy it on a big screen in TV quality. He made slow motion and fast motion videos, underwater-and night vision footage and made also some amazing landscape videos with a drone (which had tragically a fatal accident, luckily all the important drone footage was already filmed at this time).

View over the Black Forest. Screenshot from „Into the Forest“

During this three months we met as often as I could to show Bryan several more interesting locations like a pond which is especially well suited to observe mating common toads (Bufo bufo). One particular experience was a tour during a rainy night to a small valley just quite close to where I live. This area is a very good location for one of the most charismatic European amphibians, the flamboyant fire salamander Salamandra salamandra. Admittedly I was never there after dusk, and our tour topped easily everything I’ve ever seen during a salamander herping tour. We saw so many fire salamanders that we couldn’t even count all of them, but all in all we’ve seen about 60 specimens. In this area the populations of the striped fire salamander Salamandra salamandra terrestris and the spotted fire salamander Salamandra salamandra salamandra overlap and both forms also interbred. As a result of this we encountered an enormous range of different patterns. We also found a specimen which just caught an earthworm, a pair which was mating and best of all several females just giving birth to their larvae.

Filming fire salamanders during a rainy night is not exactly the most comfortable thing you can imagine

The fire salamander also plays a key role in the documentary, but not just for its charming appearance but also to raise awareness about the dangers of the chytrid fungus Bsal which entered the European continent from Asia over the amphibian pet trade. Bsal already eradicated whole fire salamander populations in Belgium and the Netherlands, and has already reached northern Germany. Sadly, it is likely to continue spreading even further through Europe.

Female fire salamander giving birth to its larvae. Photo by Markus Bühler

Another nightly tour brought us to a local population of European tree frogs (Hyla arborea). The loudness of their croaking was just incredible. This was for me also the very first time to see European tree frogs, as this species has sadly become extremely rare, mainly as a result of a lack of fitting habitats and small periodically draining ponds where they can successfully spawn. I was also quite surprised to learn about this population which is also quite closely located to some of the other areas where Bryan filmed.

European tree frog, photo by Markus Bühler

Of course the wonderfully exotic-looking (and in this case allochthonous) green lizards (Lacerta bilineata – or is it viridis? Things are complex here) of the local population here around were included as well. Bryan could even film a mated pair, and the drone footage provided some great views of their habitats within the centuries old vineyards.

Green lizard

Another reptile we hoped to find remained however elusive. The year before we made a trip to the Black Forest (which is also only about an hour to drive from here) and were able to find two specimens of melanistic European adders.

Melanistic form of the European adder, the „hell adder“

But this year we had sadly lesser luck. During our first trip to the Schliffkopf, one of the highest elevations of the Black Forest, it was despite the early time of spring extremely hot, well over 25 Celsius. On some places there was still half a meter of snow, but the heat of the sun was just too much for the adders.

Not a tundra area at Scandinavia but an upland plain at the Schliffkopf. Photo by Markus Bühler

At least we could observe some particularly nicely colored European grass frogs (Rana temporaria) in the act of mating, and this sequence was also included into the final documentary.

Mating grass frogs. Photo by Markus Bühler

We made later two further trips, but every time the weather conditions were against us. At the second tour to the Schliffkopf mountain it was quite the opposite of the last time, it was very cold with a lot of wind and fog, but next to no sunshine. Again pretty bad conditions for adders. However the fog over the forest provided some spectacular landscape shots.

Fog and clouds over the Black Forest. Photo by Markus Bühler

The view from the slopes around the Schliffkopf is really great, you can even see the Alsace behind the river Rhine.

Bryan looking to France

Our last tour to the Black Forest lead us to Kaltenbronn, an area with several bogs where we found the two adders the year before. Sadly all we found that time was a single freshly road-killed adder.

Bog area at Kaltenbronn. Photo by Markus Bühler

A photo of me from our more successful adder-tour in 2017:

One highlight was also a herping excursion to Croatia. There would be so much to say about the many things which we have seen there, but this would be way too much here. We made a tour from the island of Krk to to the very southwest of the Croatian mainland, down over Istria to the island of Cres and again back to Krk. We saw various interesting reptiles, birds and a lot of really unusual invertebrates and spectacular landscapes. We didn’t find as many reptile species as we hoped, especially snakes and scheltopusiks (Pseudopus apodus) proved to be quite elusive and hard to find. I spied only a few of scheltopusiks at the first day at Krk, but it was not possible to take any photos. One species for which we had especially big hopes to see it was the horned adder (Vipera ammodytes), one of the most venomous snakes of the European continent.

Horned adder, Krk.

It was still a lot if luck involved, but during our systematic search I could detect a tiny horned adder between some stones. This enigmatic little snake was surely one if our greatest finds during the excursion.

Bryan and the horned adder, island of Krk, Croatia.

To have at least a more southern cousin of the European adder on screen, it was also included within a short segment about our excursion. There would be still so much more to say, but I will make a break here, in hope to write anytime a future blogspot about our tour to Croatia. You can see some more photos on Bryan’s website.

A considerable part of the documentary was filmed in the Schönbuch forest, a large forest area near Tübingen. The deep and wide-ranging woods provided various interesting locations for filming, from game enclosures with red deers and wild boars to large ponds full of tadpoles. Germany is quite densely populated and even most of the nature reserves are in one way or another altered by human activities. In many cases this already happened centuries ago, so the landmarks of human activities are often deeply interwoven within the surrounding landscape.

One of the big ponds of the Schönbuch forest. Photo by Markus Bühler

One especially nice remnant of human culture was also included, the old monastery of Bebenhausen which is located just in front of the Schönbuch forest. Surrounded by centuries old wooden framework houses, its gothic architecture, ancient walls and old towers made it also a perfect location for drone footage to show the full range of the complex.The monastery was founded in 1190 and after the reformation it was among others used as a hunting lodge and the late residence of the last king of Baden-Württemberg in the early 20th century.

The old monastery of Bebenhausen. Photo by Markus Bühler

We visited also the Alter Aichwald („old oak forest“) near Denkendorf where Bryan made much of the filming of fire salamanders and other featured amphibians. We were there already years ago on our first fire salamander tour.

Fire salamander at Alter Aichwald

Bryan showed me the big badger den which he discovered and where he could make some great footage with a game camera.
I know many of those locations for nearly my whole life and have countless wonderful memories about them. To see them now in high quality documentary feels nearly somewhat surreal, especially as I was on site during many of filming sequences. I learned a lot of new things and made many new experiences, and it makes me really proud that I could contribute a little bit to this wonderful documentary. Bryan did really an amazing job to produce the whole documentary himself. He did all the cutting of the scenes, the selection and arrangement of the background music, the script (which I translated and adapted for the German version, entitled “Der magische Wald: Reptilien und Amphibien) and the digital enhancement of certain scenes. Normally such documentaries are made by whole production teams or even specialized companies.

Screenshot from „Into the Forest“

„Into the Forest“ became a really wonderful documentary especially as it focuses on animals which get despite their fascinating lives usually only little media coverage. I think it will be also quite interesting to see for everyone interested in animals, no matter if you’re European and familiar with some of the featured animals or if you are living anywhere else on the world. I could imagine that for non-European watchers it could be especially interesting to learn about some of the enigmatic animals which still dwell in such a non-exotic area, and also about the surrounding landscapes and history of Southern Germany.
You can read more about the documentary at the official website Into the Forest.
Bryan has also many of his nature and animal photos on MacroPhotoBug, wildernessshots and his instagram and Facebook-page. His documentaries are available on his YouTube channel.

Many thanks also to all who wrote suggestions, ideas and constructive criticism during the editing of “Into the forest”.

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Are crocodiles really green? – And why this is important for paleoart

If you read a comic or watch a cartoon which includes any crocodiles or alligators, you will notice that they are nearly universally green. The same applies to crocodiles in books for children, on logos or sometimes even drawings in nature books. But are crocodylians really green? To answer this question, it is important to take a look at the various modern crocodylians which includes the crocodiles, the alligators the gharials.

If you are only familiar with „normal“ crocodylians like Mississippi alligators, nile crocodiles or saltwater crocodiles, you will be possibly surprised by the diversity of colors and patterns, especially if you also take a look at the juveniles which are often much more contrast-rich than older specimens.We find near white and full black, a big range of grey, but also many shades of yellow and brown which can be even reddish. And of course there are combinations and mixes of all of them as well as fully black patterns.

Siamese crocodiles (Crocodylus siamensis) are quite flamboyant for crocodylian conditions. Wikimedia Commons, photo by Marco Almbauer

But what about green? This is not that easy to answer. We clearly see not a single crocodylian as green as the eponymous green lizard or the green iguana. At best we find something that falls somewhere in the range of greenish, for example in Nile crocodiles. But even here it seems to be not a real propper green but more a mix between yellow and grey that appears green.

Nile crocodile, Hagenbeck Zoo Hamburg

It’s quite interesting that even ancient Egyptian artists already sometimes exaggerated this to a much stronger green.

Fragment of a sarcophagus of Peteamun, 23.-25. dynasty. Museum Alte Kulturen, Schloss Hohentübingen.

The Nile crocodile Crocodylus niloticus and the West African crocodile Crocodylus suchus were also the first crocodylians which became known to European cultures. The Romans even imported some crocodiles from North Africa to exhibit them or to slaughter them in gladiator fights. We still even find some surprisingly realistic artistic depictions of crocodiles from Roman times, which were quite likely made by people who had actually either seen then themselves or had at least very good references. But besides those we find also some much more grotesque depictions as well.

West African crocodile (Crocodylus suchus), Copenhagen Zoo. Wikimedia Commons, photo by Lars K. Jensen

It’s not really that surprising that later medieval depictions of crocodylians were usually just vaguely naturalistic at best. But the green color was still a comparably common feature. During the renaissance, when cabinets of curiosities became chic, taxidermy crocodylians were quite popular items for such collections. Trading connections and the discovery of the New World and other exotic areas lead at that time to a tremendous increase of new animal discoveries and a much better understanding of the natural world. The imported taxidermy specimens of crocodylians were surely not green what makes it even stranger that the stereotype of the green crocodiles managed to persist in art.

If we look at other species we find some other crocodylians besides C. niloticus which have a vague greenish appearance. But even if we keep the slight ability of color change of some species in mind, we still don’t see anything even remotely close to a real green. The only green crocodylians which we find in the real world have their coloration from a layer of algae.

Algae-stained nile crocodile from crocodile farm Djerba Explore, Wikimedia commons. Photo by Ad Meskens

It’s hard to say how much such algae-covered crocodiles, caimans and alligators contributed to the stereotype. In some cases it’s not even that obvious anymore that the original coloration is altered by a fine layer of tiny water plants and even species which have normally not even a vaguely green touch can appear to be of that color.

Algae-stained dwarf crocodile (Osteolaemus tetraspis), Tierpark Berlin. Normally this small crocs are of a dark blackish grey.

I could imagine that this really was a factor which contributed to the cliché of the green crocodiles. Many early travelers and explores could probably see crocodylians only from some distance and usually in the water.

Orinoco crocodile Cocodrilus Intermedius – also showing the dirty mix between yellowish and grey which appears vaguely greenish. Wikimedia Commons, photo by Mauriciogq

To put the initial question – are crocodiles really green – in a nutshell, I would say that some are perhaps a little bit.

False gharial (Tomistoma schlegelii) with light-brown main color. Wikimedia commons, photo by Junkyardsparkle

But yet they are still far away from the common stereotypes. That makes it even harder to understand that we still see reconstructions of prehistoric crocodylians with truly comicesque green colors. I am fully aware that we cannot rule out the possibility that prehistoric crocodylians could have had a wider range of colors, especially as they filled many more ecological niches than the remaining modern lineages. But makes it really sense to reconstruct those forms with a color we see in no extant crocodylian species? I really don’t think so. I have to emphasize here that I am refering here only to amphibious crocodylians and crocodyliformes, and not the various terrestrial forms which had totally different ecologies. On a sidenote, I am also not refering to marine forms, which had probably again quite different color schemes and patterns, but I also really doubt that any of them was green either.

The nearly fully blackish coloration of the Mississipi alligator is quite popular among modern crocodylians. Photo taken at Wilhelma Zoo Stuttgart (but the alligators are no more on display today).

The range of colors we actually see in modern crocodylians gives paleoartists already so many possibilities to create interesting new color schemes and patterns, that it’s not even necessary to include green at all. I wrote in an earlier blogpost about a certain tendency to depict marine reptiles with extremely elaborate color scheme and why this is somewhat problematic and contrary to what we see in most bigger marine vertebrates.

Juvenile mississippi alligators have striking patterns, quite unlike the adults. That´s something really important to keep in mind when depicting juvenile prehistoric reptiles. Wikimedia commons, Photo by AThiele.

Mark Witton gave recently a really interesting and thought-provoking talk about monsterization in paleoart. This included also the importance to depict prehistoric animals not like semi-fantastic beasts but as real animals to enable people to really understand how this were once living organisms and not concept art for a sciene fiction movie.

Juvenile black Caiman from Moscow Zoo. The pattern and the strong contrast between jet-black and nearly fully white and creme-yellow is really awesome. Wikimedia Commons, photo by Rigelus

Don’t get me wrong, I really don’t say that we should now depict anything in grey, brown or yellowish colors like all the dinosaurs in the first Jurassic Park movie (except the imaginary frill of the Dilophosaurus of course…). But we should – even if we create new patterns and color schemes – still not forget to see how real animals are looking in life. In the case of extinct crocodylians we even have the chance to see some of their relatives still alive – something impossible for many other prehistoric animals without any extant relatives.

Cuban crocodiles have wonderful contrast-rich patterns even as adults. Wikimedia Commons, photo by Trisha M Shears

So, does it make sense to reconstruct extinct crocodylians and crocodiliformes with colors we don’t find in any extant species? Not really. Even more so when it comes to prehistoric crocodylians which actually are still comparably closely related with modern forms and share even a similar ecology.


A quite demonic-looking Cuvier’s Dwarf Caiman (Paleosuchus palpebrosus) in Paignton Zoo, Devon, UK. Wikimedia Commons, Photo by Nilfanion

That’s why I would not reconstruct an animal like Purussaurus, Mourasuchus or any other amphibious crocodylian or crocodiliform with a green coloration which is more pronounced than the dirty greyish-yellow of Nile crocodiles. I really think there is a reason that no modern crocodile, alligator, caiman or gharial is really green, no matter if they hunt fish, turtles or zebras and no matter if they live in a jungle river, a swamp area like the everglades or a savannah habitat.

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