 Cougars are the largest of the small cats . They are placed in the subfamily Felinae , although their bulk characteristics are similar to those of the big cats in the subfamily <unk> . The family <unk> is believed to have originated in Asia about 11 million years ago . <unk> 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 significant confidence intervals exist with suggested dates . In the latest <unk> study of the <unk> , the common ancestor of today 's <unk> , Lynx , Puma , <unk> , and Felis lineages migrated across the Bering land bridge into the Americas 8 @.@ 0 to 8 @.@ 5 million years ago ( <unk> ) . The lineages subsequently diverged in that order . North American felids then invaded South America 3 <unk> 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 <unk> , a cat just a little more than a tenth its weight . 
