In zoological classification cats belong to the Class : Mammalia (mammals - hair covered animals that suckle their young with breast milk), the Order : Carnivora (they are carnivores - they eat meat) and the Family: Felidae. Within this family there are three further subdivisions called genera (Panthera (cats that roar), Acinonyx (the Cheetah) and Felis (all other "small" cats)), and each genus contains individual species. A species of cats is a group that normally breeds and produces fertile offspring (see section on DNA below)
Wild cats inhabit all parts of the world except the extreme Arctic and Antarctic regions, Australia and the wastelands of the tundra where there is no tree cover for prey.
General characteristics of
Cats have evolved as predatory hunting animals with great agility and keen senses - particularly hearing, sight and smell. From only a few weeks of age the kittens of all species of cat (including our domesticated varieties) show instinctive behaviour typical of hunter-killers. They are extremely alert to sounds and movements, stalk, ambush, convert rigid stillness into rapid movements to pounce on their prey, and they demonstrate the typical biting and clawing actions needed to bring down and kill prey quickly.
All cats (except the lion and some feral domestic cat colonies) are solitary animals that hunt and fend for themselves. They only come into contact with members of the opposite sex during mating periods when scent in female urine attracts males to her from a long distance. Cats are also very territorial and mark out the perimeter of their "homeland" with their urine. In urban areas our domesticated cats still exhibit these behavioural traits, creating serious problems for male tom cats who inevitably fight with each other as they cross each others territories in search of on-heat females. Neutering can help to reduce the nuisance caused by calling and fighting cats, as well as reducing the number of unwanted litters.
Cats are capable of great speed over short distances - and none is faster than the Cheetah which is able to reach over 60 miles per hour (100km per hour) making it the fastest land animal on Earth.
The earliest ancestors of cats originally evolved about 200 million years ago from reptiles. Prehistoric remains of cats are few and far between but the dental pattern of modern day cats is similar to that found in fossilised creodonts - primitive fish-eating mammals which lived about 50 million years ago, but this genetic line failed to survive and there are no direct descendants today. At the same time another group of animals the miacids also had cat-like cutting teeth - they were small forest-dwelling creatures and these evolved into the carnivores of today - including some cats.
Even though everyone has heard about the "Sabre-toothed Tiger" or Smilodon - which had canine teeth 20cm or longer - this animal is not in fact related to the big cats found on Earth today. The last sabre toothed "cats" died out as recently as 30,000 years ago (based on fossil records in Britain) and possibly only 13,000 years ago (fossil records in California).
Fossils from 12 million years ago are similar to modern small cats. By 3 million years ago there were a wide variety of cats which populated the whole world except the Arctic, Antarctic, Australia and the inhospitable tundra regions. However, Australia does have some indigenous cat-like species e.g. the "marsupial cat".
There are several anatomical features such as a rounded head and a skeletal structure designed for agility which suggest that all cats (domesticated or wild, large or small) have evolved from a common prehistoric ancestor.
Generally, male and female cats are very similar in appearance. The exceptions are adult male lions which develop a mane. Usually males are slightly bigger than females of the same species.
Cats have five toes on the front feet and four toes on the hind feet, although occasionally individuals are born with more toes (an inherited abnormality called polydactyly). Cats walk on their toes and have soft pads on the toes and feet which help to reduce sound when stalking, as well as protecting the underlying bones from concussion during running and jumping.
Cats have evolved with eyes that protrude forwards from the head giving them good forward and sideways vision. The retina at the back of the eye reflects light from an area called the tapetum lucidum, and it consists of a high proportion of cells called "rods" which gives cats excellent vision in poor light - a feature that helps them to hunt around dusk and dawn. Although the image they see is useful, it lacks fine detail so they may miss small objects. Cats do have different cones in the retina for differentiating colour - but their colour vision is very poor compared to ours.
Cats have a dental profile typical of the carnivores. They have four large canine teeth at the front of the mouth which are used to grasp their prey, and large molars including two carnassial teeth (one on the upper arcade of both sides of the mouth). These are used to gnaw and slice the meat into small pieces so that it can be swallowed.
NOTE It should be noted that all cats - including domesticated species - are obligate carnivores and they cannot survive without ingesting nutrients derived from animals. CATS MUST NEVER BE FED AN EXCLUSIVELY VEGETARIAN RATION.
One genus of cat - the roaring cats (panthera), which includes the lion, tiger, leopard, clouded leopard, snow leopard and jaguar, has been determined based upon an anatomical difference in the hyoid bone apparatus. The hyoid lies at the base of the skull and connects it to the larynx. In the genus panthera it is made partly of cartilage, which allows it to move freely and so gives the vocal cords the ability to make roaring sounds. In all other cats the hyoid bone is completely ossified and rigid.
All cats have retractable claws except for the Cheetah - and for this reason it is placed in it's own genus - Acinonyx.
Cats have developed with a wide variety of coat colours and patterns. In wild cats these have evolved as camouflage. It is not surprising therefore that the snow leopard should have a very pale, light, almost white coat - as it inhabits regions frequently covered in snow, whereas it's counterpart the leopard has spots to help conceal it in forests. Tigers have stripes to conceal them in long grass, lion are tawny-brown to blend in with the savannah, and so on. Because coat colour is a genetically inherited feature breeders can influence this in their breeding.
DNA - Inheritance and gene
All cats have 38 chromosomes in each cell - except for Ocelot's and Geoffreys Cat which only have 36 chromosomes.
A species of cat is a group that normally breeds and produces fertile offspring. However, under artificial conditions - such as captivity - it is possible to cross-breed different species and create variants e.g. leopards have been crossed with lions to create leopons, lions and tigers to create ligers (father a lion) and tigons (father a tiger). The offspring are usually sterile. An exception to this "rule" is that feral domestic cats have successfully bred in the wild with wild cats.
The anatomical, behavioural and other characteristics of modern-day cats can be explained by the genetic transfer of material from one generation to another, the principle of "survival of the fittest" and by adaptation to the surrounding environment. Sometimes a desirable trait transmitted by a genetic sequence can be linked to an undesirable trait. The most notable example of this is white hair coat. White cats are often born deaf, and they are also predisposed to develop hypersensitivity and in some cases cancer of the ear flaps (pinnae) of the ears when exposed to sunlight.
Laboratory sequencing of feline DNA (the feline genome) is currently being undertaken, and as a result we shall discover more and more about the genetic component of inheritance in these species. This will not only help us to prevent and treat common diseases, but it will help us to piece together the evolutionary trail leading to modern day cats.
In addition to the behavioural characteristics of cats as predators, there are some interesting functional characteristics that are thought to reflect the cats origins as a desert-dwelling creature. One of these is the ability of cats kidneys to concentrate urine much more than other domesticated species e.g. dogs.
Cats also demonstrate some unique metabolic characteristics which set them aside from other domesticated animals such as dogs. As a result they have a specific nutritional requirement for taurine, for example, and for preformed vitamin A and for the essential fatty acid, linolenic acid.
Pictorial artifacts and
Paintings and inscriptions of cats from 2000BC in Egypt suggest that they were living with humans as domesticated animals at that time and later the cat became an important religious symbol, even being buried in their own cemeteries.
The photograph below shows an Egyptian figure of a cat dating form about 900BC.
Naturally, humans would have selected cats with a docile nature and kept those that responded positively to human behaviour. From North Africa domestication of cats spread through the Middle East, India and China but human settlements in Europe didn't have domesticated cats until the Romans introduced them much later.
Cats were kept on ships to control the rodent population and as a result the seafaring explorers from Europe carried and introduced domesticated cats all over the world.
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