Why Did Fanged Cats Have Longer Forelimbs And Sloping Backs?

[MarkGelbart]

This is the question I tackle in my latest blog entry-- http://markgelbart.wordpress.com

The Machairodontinae, which includes Smilodon fatalis and Dinobastis serus, is a sub-family of the cat family. Cats are placed right next to hyenas on the evolutionary tree, and the fanged cats are the closest cats related to hyenas.

Hyenas also have longer forelimbs and sloping backs. This build must go way back in time.

I noticed that when fighting with African hunting dogs, hyenas sit on their haunches to defend themselves from being nipped on the behind. The fanged cats must've done the same thing, only it would have been easier for them because they could use powerful paw blows as well as their biting teeth.

Anyway, check out my blog--I scanned a sketch of the Dinobastis skull recovered from Friesenhahn Cave in Texas.

[Haddy]

Good article.

There was a good book that was written a while ago, maybe 1950's or so, although there is a newer edition. It's called "The Dog in Action" by Lyon. It's about how form follows function for all breeds, regardless of shape and size. While he was studying how dogs move and/or should move properly (he was an engineer), he made comparisons with the build and purpose as well as movements of various other species. It was an interesting book and may give some additional insight.

Edited October 8, 2010 by Haddy

[Scylla]

Thanks for the article, and the one about the Paw Paws too

[siteseer]

It is an interesting question. Hyenas and were in Eurasia and Africa during the Early Miocene (roughly 20 million years ago) with sabercats present around 10 million years ago (perhaps earlier - 12-15mya?) while dogs don't reach those continents until very late in the Miocene (or around 3 million years ago). Hyenas were more diverse and generally more dog-like in appearance across much of their history. Then, about 3 million years ago the earliest apparent relatives of the four modern species (bone-cracking forms) appear. Hyena diversity declined during the Late Miocene perhaps related to a worldwide trend of increasingly cooler, drier climates. In Africa dogs diversify during the Pliocene, taking niches once occupied by hyenas. Today, only the bone-cracking hyena species and the highly-specialized (termite-eating) aardwolf survive.

Smilodon has been characterized as an ambush predator of large mammals (unknown if they hunted alone or in small groups (though there is evidence of the latter) while hyenas hunt in groups as cooperative pursuit predators. Smilodon's longer (and stronger) forelimbs have been interpreted as indicative of a "wrestler," bringing down prey and holding it down to deliver precise stabs with its sabers. I have been unable to find a reference that addresses the significance and development of longer forelimbs in modern hyenas though the increased shoulder height allows a better view of the area than other similarly-sized carnivores of more equal limb heights across a time when drier climates led to forests losing ground to grasslands. Spotting and reaching prey/carrion before your competitors is an advantage. The "sitting defense" might be a very recently-acquired behaviour taking advantage of the shorter hindlimbs or it could have been tied to the early evolution of the body form.

This is the question I tackle in my latest blog entry-- http://markgelbart.wordpress.com

The Machairodontinae, which includes Smilodon fatalis and Dinobastis serus, is a sub-family of the cat family. Cats are placed right next to hyenas on the evolutionary tree, and the fanged cats are the closest cats related to hyenas.

Hyenas also have longer forelimbs and sloping backs. This build must go way back in time.

I noticed that when fighting with African hunting dogs, hyenas sit on their haunches to defend themselves from being nipped on the behind. The fanged cats must've done the same thing, only it would have been easier for them because they could use powerful paw blows as well as their biting teeth.

Anyway, check out my blog--I scanned a sketch of the Dinobastis skull recovered from Friesenhahn Cave in Texas.