Why maned lionesses are not that special (and why they don´t baffle scientists)

Perhaps you have heard about the recent report about a lioness at Oklahoma City Zoo, which „mysteriously“ grew a mane. As usual „scientists are baffled“, at least according to the news-site which spreads the story.  However, the whole case is neither mysterious nor that unusual. The lioness at Oklahoma Zoo, her name is Bridget, is already 18 years old, what´s quite old for a lion, far older than they usually they live in the wild. Even big cats age, and like humans, they also can have a menopause, and as a consequence thereof, a change in the production of sexual hormones. We all have male and female hormones in our bodies, which are in a quite complex interaction with our metabolism. Changes of the hormone levels can result into a lot of physical changes, from increased or decreased muscle growth, accumulation or breakdown of body fat or the reduction or reinforcement of secondary sexual characteristics like body hair.

In lions, the growth of manes is controlled by testosterone (similar to the growth of beards in humans), so changes in the level of this hormone can result into an increase or decrease of mane growth (the whole thing is of course even much more complex, and also depends on the subspecies of the lion). And it doesn´t matter if it is a male lion of a female lion. A male lion with very low testosterone levels will hardly grow a mane, whereas a female lion with high levels of testosterone can grow a small mane. The origin of such an inbalance can be quite variable. It can be a congenital defect, a dysfunction of hormone producing organs or a hormone-producing tumor for example. It can be (more likely in males than females) a result of an accidental or artifical removal of the gonads. Something like that is likely if a comparably young lion shows for example a mane which is atypical for its sex. But if a lion, which has been totally normal for its whole life, starts to exhibits unusual mane growth at old age, it is highly likely a result of the hormone imbalance after the menopause. The production of typical sexual hormones decreases, and the effects of the normally suppressed antagonistic hormones can become more visible.

I have seen such cases myself. There were two lion-sisters at Stuttgart Zoo, Schiela and Elektra (both 1994-2008), which grew both a well visible mane at old age. Here is a photo of one of them, which I took in 2003:

Maned lioness at Wilhelma Zoo, Stuttgart 2003

As you can see, the mane resembles those of a young male lion which just hits puberty. It´s neither as long, nor as extensive or dark as those of a typical male lion. It is more the feline equvialent of the facial hair seen in some (often more elderly) women.

Lioness with mane, Wilhelma Zoo, Stuttgart, 2003

It was sadly not that easy to take photos of her, but you can see some better ones here, here and here.

Schiela and Elektra were also not the only other known case of old lionesses with manes, and there is really nothing about them that would baffle scientists.

Lioness with mane, Wilhelma Zoo, Stuttgart, 2003

 

Veröffentlicht unter Populäre Irrtümer, Säugetiere, Teratologie | Hinterlasse einen Kommentar

Photo of the Day: Chiemsee Pike

Pikes have always been among my favourite native European freshwater fishes. Their taxonomy has  become much more complex in recent years, when two additional European species were described, so that Esox lucius is no more the only of its kind in Europe. This particular topic will (hopefully) anytime be featured in a more extensive blogpost about the amazing diversity of pikes.

Last year was a particularly good one for me in terms of finding pikes in the wild. Besides some really impressive specimens I saw during my trip to Königssee and three small ones I discovered in a lake at the Swabian Alps, I could also take some underwater photos of several young pikes at Chiemsee. This one is likely the best, which shows a pike of around 15-20 cm:

Northern Pike, Lake Chiemsee

You can see very well how the camouflage pattern of the pike blends within the structure of the underwater vegetation.

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The Art of Xylotheques – Wooden Books about Woods

Xylotheques are quite likely the most artistic and beautiful examples of herbaries. Dating back to the early 18th century, they were still to some degree made in the tradition of the old cabinets of curiosities, which combined all fields of nature with arts and crafts. They were dedicated to educate about the characters and traits of the various trees and shrubs of a certain area.

In contrast to a simple casebound herbary, which usually only includes preserved leaves and other pressed parts of a plant, the „books“ of a xylotheque also includes the massive wood and often many more parts of a tree. Every book is made from the wood of one kind of tree or shrub, with the spine of the book covered with bark, and sometimes even specific lichens.

The insides can include dried branches and leaves, seeds, cones, little wooden containers with pollen and standardized cubes of wood to show its  specific weight. There can be also cross-sections of branches, dried roots and charcoal.

The backbone of the book has also a removable panel at the inside, with a piece of paper with a written description of the tree and the content of the book.

There were never many xylotheques, and they have been always quite worthy, as it was quite expensive to make them. This examples are from the xylotheque exhibited at the University of Hohenheim, which includes a large number of wooden books from two different series.

This smaller books are lesser complex in construction and also include not as much inventory:

 

 

 

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The Tarbosaurs of Warsaw

Last year I made a city holiday at Warsaw and took the opportunity to visit a lot of museums there. I was especially eager to see the Museum of Evolution, which is located in the monumental Palace of Culture and Science. One of the exhibition rooms has a whole gang of Tarbosaurs on display, including some famous specimens. Tarbosaurus gets much lesser attention than Tyrannosaurus, so I thought this would be a good chance to post some photos of the skeletons at Warsaw.

That´s likely the most famous one:

The information table next the the left skeleton is around 1,8 m in height, so this specimen was only a subadult with a hip height of not much over 2 m in life, with a total length of somewhat over 4 m or so.

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Tarbosaurus and Tyrannosaurus seem really quite similar at first look, but if you look at the proportions of their skulls, you can see that the one of T-rex was significiantly more massive and especially also much broader.

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A photo which shows how the specimens was excavated:

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There is also a cast of a complete skeleton of a pretty big specimen, which easily dwarves the other skeletons nearby.

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It was not easy to get them all completely on a photo, but it gives you an idea about the massive size difference.

There was also a cast of another skull and some isolated bones as well:

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And last but not least some old paleoart:

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Photo of the Day: Sri Lankan Spotted Chevrotain

Today´s photo fo the day features one of the smallest extant artiodactyls, the tiny Sri Lankan Spotted Chevrotain (Moschiola meminna) from the South Asia animal section of Haus der Natur, Salzburg:

Sri Lankan Spotted Chevrotain (Moschiola meminna), Haus der Natur, Salzburg

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Curiosity of the Day: Whale bone chairs

Today´s curiosity of the day are chairs made of whale bones. The first one is constructed of two large cervical vertebrae and apparantly pieces of ribs for the chair legs. It is exhibited in the Zoological Museum at Copenhagen, Denmark.

Whale bone chair, Zoological Museum Copenhagen

I have no idea how comfortable this chair was to sit on, but I really like the nearly gigeresque Design which would surely fit very well into a Science Fiction movie, for example for a Predator spaceship.

Here is another example of a different construction, made from the bones of a fin whale. It was exhibited at the Staatliches Museum für Naturkunde Karlsruhe (State Museum of Natural History Karlsruhe) but is now sadly no more on display.

Whale bone chair, State Museum of Natural History Karlsruhe

 

Veröffentlicht unter Anatomie, Curiosity of the Day, Wale | Hinterlasse einen Kommentar

Photo of the Day: A frizzy-haired freak roe deer

Here is a pretty unusual specimen of a Western roe deer (Capreolus capreolus) with frizzy-haired fur. This was apparantly the result of an unusually strong production of cutaneous sebum.

Frizzy-haired freak roe deer Haus der Natur, Salzburg

Detail of the fur:

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Photo of the Day: Sumatran Rat

The Sumatran porcupine and the moonrat are now in good company with another little-known critter from the same part of the world, the Sumatran rat (Rhizomys sumatrensis). Photo taken at Haus der Natur, Salzburg:

As in the Sumatran porcupine, this old taxidermy specimen has faded somewhat, living Sumatran rats are usually somewhat darker and more greyish.

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Photo of the Day: Moonrat

It´s again obscure mammal day, so here´s a moonrat (Echinosorex gymnura), a long-tailed oppossum-lookalike related to hedgehogs. This specimen is again from Haus der Natur, Salzburg:

Another photo to show its size:

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Photo of the Day: Sumatran porcupine

Writing blogposts, even quite short ones, often requires a substantial amount of time. Finding topics to write about is not the problem, and I already have more photos for potential blogposts in my archives, than I could ever write. So I decided to try posting at least some more photos of interestig subjects without much text, at best a post per day. I´ll see how well it works. I´ll start with a photo of a pretty obscure mammal you´ll quite rarely encounter in any museum, the Sumatran porcupine Hystrix sumatrea. This specimen is from the pretty awesome museum „Haus der Natur“ at Salzburg, Austria. Note that this is a pretty old taxidermy specimen with faded colouration, in life they are much darker.

Sumatran porcupine Hystrix sumatrae, Haus der Natur, Salzburg.

Detail of the head:

As you can see the quills are much lesser pronounced than in the common crested porpcupine Hystrix cristata you usually see in zoos:

 

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