Friday, November 07, 2014

The brain of the mammoth

Aficionados of extinct animals are sorry we just missed (or hunted to extinction) beasts like the woolly mammoth, the mastodon, and the wooly rhinoceros. But, unlike the dinosaurs, the great mammals have left us some startling specimens frozen in soil and permafrost.
The mammoth called Yula is 39,000 years old and hails from Russia - the shores of the remote Laptev Sea, to be precise. Found in 2010 and now in the hands of the Russian Geographic Society, Yula (a youngster 6 to 9 years old) turned out to have a remarkably preserved brain, showing folds, blood vessels, etc.  Paleontologists are ecstatic about having a look at what made the mammoth tick. 
Are rhinos more your thing? Darren Naish's Tetrapod Zoology blog explores what we know- and what we think we know.  It seems the woolly rhino (Coelodonta antiquitatis), usually depicted as resembling a modern rhino in a mink coat, instead might have had a whiff of musk ox about its stocky, long-furred, humped appearance. Or maybe not - prehistoric artists in France depicted it both ways, and Naish suggests the coat, at least, varied with the seasons.  They apparently had low-hanging heads and huge horns, and another British paleontologist envisioned them chomping their way through grasses "like giant furry lawnmowers."
A very large and complete woolly rhino skull was just found in Cambridgeshire in the UK, so that's another piece of evidence under study.  Finally, there's another recent find of note: a spear, about 13,000 years old, made of rhino horn. It was found in Siberia and still looks lethal. It's the first known spear of its type and comes from a place where humans were not previously thought to have lived in that era.
The northern plains of old North America and Eurasia must have been very impressive places. While the mammoth-based economy in the movie 10,000 BC is ridiculous (as are occasional claims the mammoth survives to this day - alas, it does not), these were really big lawnmowers.

 
The mammoth, Mammoth primigenius, on a recent Russian postage stamp.

8 comments:

Laurence Clark Crossen said...

How can Bergman’s Rule explain End Pleistocene giantism when the mammoths in the far north were no bigger than present day elephants? It cannot. Bergman’s rule must be a trivial factor that cannot account for more than a small fraction of that giantism.

Laurence Clark Crossen said...

If Bergman's rule was the cause, then the mammoth's in the north should have been larger than the mammoths in the south and larger than the present day elephants in the south. They were not.

Laurence Clark Crossen said...

The Imperial or Columbian mammoths were exceptionally large but had a more southerly distribution.

Matt Bille said...

I don't think Bergman's Rule is without exceptions. There are other ways to adapt to temperature besides size.

Laurence Clark Crossen said...

Correct. Then you are saying the mammoths could have been cold adapted by some other means. There are obviously many means to do so. The question is, if Bergman's Rule does not explain End Pleistocene giantism, then what does? Bergman's Rule cannot explain it because it takes place in all climates.

Laurence Clark Crossen said...

By "all climates" I meant all climate zones, such as Tropical, Temperate, Arctic or the twelve climate types, Subartic, etc.

Matt Bille said...

Just as there are different ways to adapt to temperature, there are different reasons to become huge. Ask Argentinosaurus, for which I assume giantism was basically a strategy to avoid predators. But you may be complicating things too much. There are many ways to adapt to cold temps, but being big and hairy may have been the mammoth's way.

Laurence Clark Crossen said...

I think that one has to explain the general presence of giantism during the Pleistocene. There must be a general cause since it was the rule, and Bergman's Rule was not it. I suggest that it is much more likely to have been a warmer climate than we have at present, rather than a colder climate, that caused the giantism. For example, when the Irish Red Deer were introduced to New Zealand during the 19th century they quickly grew to 50% larger than they had been thanks to the abundance of fodder. In a warmer world there would be more abundant plant life that would tend to produce the giantism.