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
Central Institute for Experimental Animals goal was set to assist the scientific bodies in finding animals of the highest quality. In 1979, a workshop was organized in Japan under the auspices of ICLAS and the International Cancer Research Workshop (ICREW) with representatives from the governing board of ICLAS, members of the ICLAS working party, and a number of experts from throughout the world. At that time, the planning of an ICLAS Monitoring Center System and the preparation of an International Manual on Genetic Monitoring, which had been in development for some time, was progressing well. The final proposal was later approved by the Board as