Cougars - Taxonomy and Evolution

Taxonomy and Evolution

The cougar is the largest of the small cats. It is placed in the subfamily Felinae, although its bulk characteristics are similar to those of the big cats in the subfamily Pantherinae. The family Felidae is believed to have originated in Asia approximately 11 million years ago. Taxonomic research on felids remains partial and much of what is known about their evolutionary history is based on mitochondrial DNA analysis, as cats are poorly represented in the fossil record, and there are significant confidence intervals with suggested dates. In the latest genomic study of Felidae, the common ancestor of today's Leopardus, Lynx, Puma, Prionailurus, and Felis lineages migrated across the Bering land bridge into the Americas approximately 8 to 8.5 million years (Mya) ago. The lineages subsequently diverged in that order. North American felids then invaded South America 3 Ma ago as part of the Great American Interchange, following formation of the Isthmus of Panama. The cougar was originally thought to belong in Felis (Felis concolor), the genus which includes the domestic cat. As of 1993, it is now placed in Puma along with the jaguarundi, a cat just a little more than a tenth its weight.

Studies have indicated that the cougar and jaguarundi are most closely related to the modern cheetah of Africa and western Asia, but the relationship is unresolved. It has been suggested that the cheetah lineage diverged from the Puma lineage in the Americas (see American cheetah) and migrated back to Asia and Africa, while other research suggests the cheetah diverged in the Old World itself. The outline of small feline migration to the Americas is thus unclear.

Recent studies have demonstrated a high level of genetic similarity among the North American cougar populations, suggesting that they are all fairly recent descendants of a small ancestral group. Culver et al. suggest that the original North American population of Puma concolor was extirpated during the Pleistocene extinctions some 10,000 years ago, when other large mammals such as Smilodon also disappeared. North America was then repopulated by a group of South American cougars.