Cat Evolution

The Felidae family consists of 6 genera and 38 species.

The main group; Felinae, with 26 species, includes the puma (F. concolor), largest of the genus; the ocelot (F. pardalis); the serval (F. serval) and many species of smaller wild cats, as well as the domestic cat (F. catus). The other main gerera are Lynx which include 5 species including the bobcat (L. rufus); the clouded leopard Neofelis nebulosa, the marbled cat Pardofelis mamorata, and Panthera which also has 5 species; the jaguar (P. onca), the leopard (P. pardus), the tiger (P. tigris) and the lion (P. leo). The cats are indigenous to every continent except Australia and Anarctica.

The domestic cat was named Felis catus by Carolus Linnaeus in his Systema Naturae of 1758. Then in 1775, Johann Christian Daniel von Schreber named the Wildcat Felis silvestris. The domestic cat was considered a subspecies of the Wildcat: by the strict rule of priority of the International Code of Zoological Nomenclature the name for the species thus ought to be F. catus since Linnaeus published first, and so almost all biologists use F. silvestris for the wild species, using F. catus only for the domesticated form.

In opinion 2027 (published in Volume 60, Part 1 of the Bulletin of Zoological Nomenclature, March 31 2003) the International Commission on Zoological Nomenclature "conserved the usage of 17 specific names based on wild species, which are predated by or contemporary with those based on domestic forms", confirmed F. silvestris for the Wildcat and F. silvestris catus for its domesticated cousin. F. catus is still valid if the domestic form is considered a separate species. Recent DNA and comparative bone research shows that the separate species name F. catus is correct after all.

How and what period various species of wild cat became domesticated is hard to establish. In 2004, a grave was excavated in Cyprus that contained the skeletons, laid close to one another, of both a human and a cat. The grave is estimated to be 9,500 years old indicating the earliest known feline-human association however, the ancestors of the cat began with the Creodonts some 50 million years ago. These mammals were only 12 inches high at the shoulder with thick necks and long bodies. The creodonts were to eventually become extinct, but one form, Miacoidea, would continue to evolve. Early Miacids were double the size of creodonts, with slender heads, short legs, and long bodies. Some species were tree dwellers, others lived on the ground. They probably fed on invertebrates, lizards, birds and smaller mammals. Miacoidea can be divided into two families: the Miacidae and the Viverravidae. The Miacidae evolved into the caniforms (dogs, bears, raccoons and weasels), while the Viverravidae evolved into the feliforms (cats, hyaenas and mongooses).

The first true cat to arise from Viverravidae was Proailurus (first cat") around 30 million years ago. Proailurus was a compact animal, just a little larger than the domestic cat with a long tail, sharp claws and teeth, and walked plantigrade or flat-footed. By 20 million years, Pseudaelurus had emerged in North America and Europe. Pseudaelurus walked digitigrade on the tips of its toes. This is the cat from which all extinct and living cats of the family felidae are believed to have arisen, and even that long ago, the traits that make all cats superb predators were in place – stabbing teeth, powerful jaws, flesh ripping claws, agile bodies with flexible limbs and excellent binocular vision. Within this genus, there were larger and smaller species varying in size between 220lb (100kg) to 64lb (29kg) but pseudaelurus evolved to approximately the size of a cougar by the time it died out.

Other branches of the feline family tree originating with pseudaelurus gave rise to Dinofelis ("giant cat") that had flattened canines considerably shorter than those of the sabre-tooth Machairodus. This cat evolved to hunt large grazing animals and likely became extinct due to diminished food supply having become too selectively adapted for specific prey.

About nine million years ago, two million years after the cat family first appeared in Asia, these carnivorous predators entered North America by crossing the Beringia land bridge connecting Siberia and Alaska.

At some point, several American cat lineages returned to Asia. With each migration, evolution changed these forefathers of all cats into a variety of species, from ocelots and lynxes to leopards, lions and the lineage that eventually led to the domestic cat.

This modern history of the family, known as Felidae, is based on DNA analyses of the 37 living species performed by Warren E. Johnson and Stephen J. O'Brien of the National Cancer Institute and colleagues elsewhere in 1997.

Before this, taxonomists had difficulty classifying the cat family because the fossil record was limited and many of the archeological skulls lacked uniqueness. One system divided the family into Big Cats and Little Cats but Dr. Johnson and Dr. O'Brien believed most living cats fell into one of eight lineages.

Having made further DNA analyses, these researchers illustrated a complete family tree that assigned every cat species to one of the lineages. They also integrated their tree, which is based solely on changes in DNA, with the fossil record. The fossils, which are securely dated, allow dates to be assigned to each fork in the genetic family tree.

Knowing when each species came into existence, the research team was able to reconstruct a series of at least 10 intercontinental migrations by which cats colonized the world. For example, the cheetah, now found in Africa, belongs to a lineage that originated in North America and approximately three million years ago migrated back across the Bering land bridge to Asia and then Africa.

Sea levels were low from 11 million to 6 million years ago, enabling the first modern cats to spread from Asia west into Africa, creating the caracal lineage, and east into North America, generating the ocelot, lynx and puma lineages.

The leopard lineage appeared around 6.5 million years ago in Asia. The youngest of the eight lineages, which led eventually to the domestic cat, emerged some 6.2 million years ago in Asia and Africa, either from ancestors that had never left Asia or more probably from North American cats that had trekked back across the Bering land bridge.

Sea levels then rose, confining each cat species to its own continent, but sank again some three million years ago, allowing a second round of cat migrations. It was at this time that the ancestors of the cheetah and the Eurasian lynxes colonized the Old World from the New.

It was not until 4000BC to 5000BC that there is much evidence of true domestication. This coincides with the appearance of permanent settlements based around farming. Humans gained rodent-catchers while cats gained shelter and supplemented their diet. Cats are often in company with humans, consuming leftovers and providing that may otherwise attract vermin or disease. Because of these roles, cats and humans have a long history together.