Extinct Pleistocene Ecomorphs of the Cougar (Puma concolor) and the Timber Wolf (Canis lupus)

Genetic evidence suggests all present day cougars found in North America descend from a population of the big cats that lived in northeastern South America 10,000 years ago even though the fossil record shows cougars did live in North America during the late Pleistocene.  Cougar fossils have been found in at least 15 sites in Florida and 2 in Georgia, and they date to between ~130,000 BP- ~12,000 BP.  Yet, cougars that lived in North America during the Pleistocene left no living descendents–apparently they became extinct along with most of the rest of the Pleistocene megafauna.  This seems odd because modern cougars are well adapted to prey on deer and small game that survived the end Pleistocene extinctions, and Pleistocene cougars did not significantly differ morphologically from modern cougars.

The Pleistocene cougar was a large ecomorph.  An ecomorph is defined as a local variety of a species whose appearance is determined by its ecological environment.  Pleistocene cougars averaged 5% larger than modern cougars.  The color of their coat is unknown but it may have been spotted.

A Florida panther in captivity.  Cougar kittens are spotted–evidence they evolved from a spotted ancestor.  This particular adult has retained spots.  Pleistocene cougars in North America may have been spotted.  A Florida panther is the same species as a cougar.  It’s now not even regarded as a separate subspecies by most experts.

Rob Klein, the stupid looking asshole on the far right, is the jerk who killed this beautiful animal in Alberta, Canada. (His facial expression is reminicent of those seen on Nazi concentration camp guards during WWII.)  This cougar specimen weighed over 200 pounds.  This unusually large specimen is probably what the average size was for a Pleistocene male cougar.

Even the larger Pleistocene cougars should have been able to survive on white tail deer, a species that increased in numbers when competing megafauna prey species became extinct.  The reason why this cougar ecomorph went extinct is a mystery.  Perhaps this ecomorph was adapted to live in an environment where prey was not scarce, and there may have been a decades long delay before deer populations increased in response to the disappearance of other megafaunal prey species such as horse, llama, and peccary.  Maybe the last surviving Pleistocene carnivores, combined with human hunters, had no other alternate prey and therefore decimated deer populations, so that even this species declined to such low numbers that cougars had too little to eat.  The  cascade effect of losing so many prey species in the environment  almost doomed white tail deer as well because they were one of the few prey species left for predators to feed upon. The disappearance of the cougar from North America suggests a period of time when even white tail deer became scarce.  The genetics study does show that cougars must have been absent from North America for at least 1 breeding generation (about 10 years)  because there’s no evidence the South American founder population ever bred with the North American ecomorphs.  Recolonization of North America by cougars must have been rapid and probably occurred in less than 200 years whenever white tail deer populations rebounded.   Cougar bones have been found in early Holocene-dated archaeological sites–North America was not without cougars for long.

South American cougar populations have greater genetic diversity than those of North America.  There are 5 subspecies of South American cougars compared to just 1 in North America.  (Florida panthers are no longer considered by some to be a different subspecies.)  Florida panthers almost became extinct from inbreeding 20 years ago, but wildlife officials introduced 8 female cougars from Texas, and the population has since tripled.

Genetic studies show a similar history for the jaguar (Panthera onca).  This cat also disappeared from North America and most of South America following the extinction of the Pleistocene megafauna.  It too survived in a refuge located in northeastern South America.  This population eventually recolonized the rest of that continent as well as the southern parts of North America.  Man has probably stymied the further spread of this species.  The last stand refuge shared by cougars and jaguars was probably an area of rain forest uninhabited by man that retained enough game to support a significant population of predators.

The Pleistocene armadillo (Dasypus bellus) has been found to be genetically similar to the modern day 9-banded armadillo (Dasypus novemcinctus).  I hypothesize the modern species is simply a dwarf ecomorph of the larger Pleistocene species.  From a refuge located in South America this dwarf ecomorph has recolonized much of its former range.  This scenario is similar to that of the big cats mentioned above, but it occurred within written historical times. (See https://markgelbart.wordpress.com/2012/08/19/is-the-9-banded-armadillo-dasypus-novemcinctus-a-dwarf-mutation-of-the-pleistocene-species-dasypus-bellus/)

An Alaskan gray wolf.  Modern Alaskan gray wolves are not descended from the wolves that lived here during the Pleistocene.  Those wolves became extinct when the megafauna became extinct.  Instead, modern Alaskan wolves descend from wolves that recolonized the region some time during the Holocene.

The timber wolves living in Alaska during the late Pleistocene were a large ecomorph that also left no living descendents, according to the genetic evidence.  Their anatomical characteristics suggest they were a robust animal well adapted to hunt large now extinct megafauna.  Dire wolves (Canis dirus), common in the rest of North America, never ranged this far north, and the timber wolves living in Alaska then occupied the dire wolf niche.  The Alaskan timber wolf ecomorph became extinct when the Pleistocene megafauna disappeared.  The timber wolves currently living in Alaska descend from wolves that lived elsewhere in North America during the Pleistocene.

Cougars vs. Wolves–the latest updates

The age old war between cougar and wolf has been re-ignited since the latter has been re-introduced to the Rocky Mountains of the United States.  The Teton Cougar Project has recorded 5 cougar kittens killed by wolves.  Meanwhile, a mother cougar killed a yearling wolf and fed it to her kittens.  In Montana cougars have killed 2 adult radio-collared wolves.  In one case they were battling over an elk carcass, and the wolf was left uneaten.  In the other instance the cougar actively hunted, killed, and ate the wolf.

References:

Culver, M. et. al.

“Genomic Ancestry of the American Puma”

Journal of Heredity 2000

Leonard, J.A.; et. al.

“Megafaunal Extinction and Disappearance of Specialized Wolf Ecomorph”

Current Biology 2007

Morgan, Gary; and Kevin Seymour

“Fossil History of the Panther (Puma concolor) and Cheetah-like cat (Miracinonyx inexpectus) in the Florida Pleistocene

Bulletin of the Florida Museum of Natural History 1997

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Tags: armadillo, Cougar, cougar vs. wolf, jaguar, Pleistocene ecomorphs, timber wolf