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
Animals (Scientific Procedures) Act 1986 additional protection over other vertebrates under the Act. Revised legislation came into force on January 1, 2013. The Act has been expanded to protect - The definition of regulated procedures was expanded to - ASPA also regulates the modification of genes in protected animals if this causes the animal pain, suffering, distress or lasting harm. Other considerations in the Act include animal sources, housing conditions, identification methods and the humane killing of animals. This legislation is widely regarded as the strictest in the world protecting animals used in research. Those applying for a license must explain why such research cannot