Panthera atrox: the 1007 Pound Giant Lion

An extinct species of lion ( Panthera atrox ), similar but larger than the extant African lion ( P. leo ), occupied open habitat in North America from California to South Carolina and Florida for over 300,000 years.  The American lion evolved from the also extinct Eurasian cave lion ( P. spelea ) when the ice sheet that covered Canada isolated the 2 populations from each other. The 2 species never re-connected during interglacials because extensive spruce forests, an unfavorable habitat for lions, grew between them.  Fossil evidence of large carnivores is relatively uncommon because their populations are smaller than those of their prey. But there are 2 fossil sites that preserved a considerable number of carnivores due to unusual circumstances, and scientists were able to collect enough lion specimens from them to study and compare the anatomy of the species as a whole.  The 2 sites are Natural Trap Cave in Wyoming and the Rancho La Brea Tar Pits in California. Scientists estimated average body size and the results were astounding.

Image result for 1000 pound liger

Hercules is the world’s largest cat. It is a 922 pound lion x tiger hybrid that lives at the Myrtle Beach Safari Preserve in South Carolina.  It is smaller than the estimated size of the largest known fossil specimen of North American lion, an extinct species that formerly lived coast to coast.

The largest male Panthera atrox specimen came from an animal that was estimated to weigh 1007 pounds, though the average male weighed 544 pounds.  The largest female American lion was estimated to weight 577 pounds, while the average was 390 pounds.  By contrast the average extant African male lion weighs 392 pounds.  This means the average female American lion was about the size of the average male African lion.  The large difference in size between the sexes, known as sexual dimorphism, suggests American lions lived in social prides like their African cousins.  An 1000 thousand pound lion would be too large and slow to hunt successfully enough to sustain its bulk, but instead relied on the smaller more agile females to secure all the bison, horses, and camels he required.  A large pride could probably even take down a full grown mammoth.

The large size of the males helped them fend off other male lions that wished to usurp their mating rights and kill their offspring.  The enormous powerful males could also aid in protecting the pride’s kills from competing carnivores such as bears, saber-tooth cats, and dire wolves.  American lions had longer legs and bigger braincases than African lions, so they were faster runners and smarter as well.  P. atrox really was a king of the beasts.

Reference:

Wheeler, H.T; and G.T. Jefferson

Panthera atrox: Body Proportions, Size, Sexual Dimorphism, and Behavior of the Cursorial Lion of the North American Plains.”

In Papers on Geology, Vertebrate Paleontology, and Biostratigraphy in Honor of Michael O. Woodburne edited by L.B. Albright III

Museum of Northern Arizona Bulletin 65

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