Felidae is the taxonomic family of the cats, and is the most strictly carnivorous family of the Carnivora. It comprises three extant and two extinct subfamilies. The living subfamilies are the Pantherinae (the big cats), Felinae (small cats) and Acinonychinae (cheetahs); the extinct subfamilies are the Machairodontinae (sabretooth cats) and Proailurinae (primitive cats). Recent genetic studies have cast doubt on the validity of placing cheetahs in their own subfamily, however – there is considerable evidence that they are more closely related to the Felinae than originally assumed. Historically, cats have been classified largely according to morphology, nowadays they are more frequently classified based on genetic similarity; this has led to quite a few changes in feline taxonomy.
All cats are carnivores and most are exclusively so. With the exception of the cheetah, all cats have retractable claws. Like most carnivores, cats have large, robust canine teeth; this was especially notable in the extinct Machairodontinae, the sabre-toothed cats, but the trait persists. The clouded leopard and Bornean clouded leopard have the largest canine teeth relative to their body size of any living predator: indeed, the teeth of these cats are similar in size to those of the tiger, which is more than twice their length and up to six times their mass. Cryptic coloration is common as well, and even some cats which have single-colored coats as adults are spotted as kittens, examples of this are the lion, cougar and Canadian lynx.
Traditionally, Pantherinae consisted of the roaring cats, though nowadays three other cats, which cannot roar, are grouped in this subfamily. Considerable debate is centered over recent genetic findings that suggest that the snow leopard is actually the most basal of the pantherines. It is usually placed in its own genus, Uncia, but these more recent findings would place it in Panthera, making it the only member of that genus that is unable to roar.
The subfamily Acinonychinae, in addition to being disputed, contains only a single genus and species. The extinct american cheetah, Miracinonyx, is believed to be an example of parallel evolution, rather than a particularly close relative. Newer research suggests that both lineages descended independently from a puma-like common ancestor, which was also likely the ancestor of the modern Puma genus. The cheetah also displays most of the features associated with the small cats, other than size. It can purr, unlike any of the pantherines, and also unlike most other large cats, adult cheetahs mew. In most other cats, mewing is mostly limited to kittens.
- Genus Acinonyx
- Acinonyx jubatus - Cheetah (Fastest of all land animals)
The subfamily Felinae consists of the small cats. Though referred to as small, there are several larger members. The cougar, Puma concolor can be over 2m in length and up to 100kg in weight, making it larger in the general case than the leopard or snow leopard, and both the Eurasian lynx and the caracal can exceed 25kg. The smallest member of the Felinae is the black-footed cat, about the size of a half-grown domestic kitten at less than 1.5kg fully grown.
All members of Felinae have some similarities, however. All of them can purr both while inhaling and exhaling, and nearly all have spots or other camouflaging markings as kittens. Many retain these markings as adults, too. Many small cat species have visually distinctive features, such as spotted coat patterns or tufted ears. All are aggressive hunters, using a variety of hunting styles. Some, like the bobcat, may take prey many times their own size, while others like the caracal or serval are capable of leaping over 3 meters vertically to catch birds in flight.
- Genus Caracal
- Caracal caracal - Caracal (AKA Persian lynx, though it's not very closely related to the lynxes.)
- Genus Leptailurus
- Leptailurus serval - Serval (Closest living relative of the caracal.)
- Genus Profelis
- Profelis aurata - African golden cat (Closest living relative of the caracal and serval. There is ongoing dispute about its proper classification.)
The Machairodontinae, or sabre-toothed cats, were a group of large, tiger-like cats which lived from the Miocene to the late Pleistocene eras. There were two broad groups of them, the dirk-toothed cats and the scimitar-toothed cats. The dirk-tooths are the sabre-toothed tigers that most are familiar with, with long, flat upper canine teeth. The scimitar-tooths have shorter, stouter canines and are generally smaller and lankier, built more like a cheetah than like a lion. The odd Xenosmilus was the exception, having stout scimitar-teeth, but having the more leonine build of the dirk-toothed cats.
Many things are unknown about the Machairodonts. Though they are often likened to the modern tiger, the degree to which this simile is accurate is uncertain. Evidence suggests that they should have been able to roar, but the same skeletal evidence suggests that the snow leopard should be able to, and yet it cannot. Artists have reconstructed various Machairodonts as looking like sabre-toothed lions, cougars, jaguars, cheetahs and even lynx. Forest-dwelling species may indeed have had tiger-like markings, as they would have served as effective camouflage, but this is little more than conjecture, and they may have looked quite different from any modern cat. Their hunting techniques were almost certainly different.
There were a large number of sabre-toothed animals which were not cats; these include the marsupial Thylacosmilus, the Barbourfelidae and the Nimravidae.
- Scimitar-toothed Machairodont genera
- Dirk-toothed Machairodont genera
Sources: Wikipedia, "1996 Taxonomic and Legal Status of the Felidae" by Alan Shoemaker, lots of assorted pages on carnivores, cats and mammals in general across the internet.