Catís Anatomy



Catís Anatomy
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.

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 sequencing

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.