Felidae Oligocene, about 25 million years ago, with the appearance of "Proailurus" and "Pseudaelurus". The latter species complex was ancestral to two main lines of felids, the cats in the extant subfamilies and a third major group of extinct cats, which are assigned to the subfamily Machairodontinae. The machairodonts included the saber-toothed cats such as the "Smilodon". The "false sabre toothed cats", the Barbourofelidae and Nimravidae, are not true cats, but are closely related and together with Felidae and other cat-like carnivores (hyaenas, viverrids and mongooses) make up the feliform carnivores. Results of mitochondrial analysis indicates that all the Felidae descended
Felidae Conservation Fund Yellowstone ecosystem by examining predation, behavior associated with human development, and interactions with wolves, grizzly bears and black bears. The project is operated by Craighead Beringia South with support from Felidae. The Southern California Puma Project examines the progress and implications of habitat fragmentation as puma populations in Southern California become more isolated. Felidae is collaborating with UC Davis Wildlife Health Center on this study, which has radio-collared more than 50 pumas over 7 years. The Asiatic Cheetah Project in Iran is the first detailed ecological study of the critically endangered Asiatic cheetah. Researchers in Northern Iran work to gain