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
On the Track of Unknown Animals by complaining that "The Press has made such a laughing-stock of the Loch Ness Monster... that no scientific commission has ever dared tackle the problem" and ends with the wish that any new species are not merely slaughtered for trophies: "Have pity on them all, for it is we who are the real monsters." Reviewers praised the breadth of study, careful citation and the author's knowledge but it was criticized for being somewhat shallow and "overly long and rambling." On the Track of Unknown Animals On the Track of Unknown Animals is a cryptozoological book by the Belgian-French zoologist Bernard