Zoology

The Cheetah Anatomy Built for Speed



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"The Cheetah Anatomy Built for Speed"
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The cheetah is unique, the only species in its genus, so different from other cats that until the twentieth century it was often assumed to be a type of dog. There are certainly similarities between the cheetah and the dog, most notably the structure of the paw, but whilst the fastest dog, the greyhound can reach impressive speeds of about 45 mph, the cheetah is capable of an amazing 70 mph. Furthermore the cheetah can achieve these speeds within three seconds, which is still superior to most sports cars available today.

Providing the power behind the cheetahs land speed record are its muscles. The cheetah requires vast amounts of oxygen to fuel it's muscles and to this end the cheetah has enlarged nostrils, sinuses, lungs and heart, furthermore whilst running the respiratory rate will climb from 60, to double the human capacity, 150 breathes per minute. However the really impressive trick with the cheetah's muscles are that they are rich in 'fast twitch' muscle fibers, with up to a 20% higher concentration than other high performance mammals such as horse or indeed greyhounds, these fibers not only specialize in providing power rather than endurance but can work effectively for a few minutes when oxygen is in short supply through anaerobic respiration.

Whilst the muscles power the locomotion, the cheetah's skeletal structure is fundamental in achieving its incredible speed, dictating the distinctive running style. A single stride of a cheetah can be a massive seven meters, the same as the much larger race horse and while the horse will complete 2.25 strides per second the cheetah will complete 4. There are two occasions during this stride when none of the cheetah's paws are in contact with the ground; when the legs are fully extended, and when they are fully contracted under the body. This stride is only possible due to a flexible spine, which not only flexes to allow the gape when at full stretch, but acts much like an archer's bow, a store of energy which snaps the legs back under the body. In conjunction with the spine the range of movement is made possible by pivoting hips and shoulders that are not attached to the collarbone.

This immensely powerful and flexible body is extremely light weight, the average cheetah only weighing between 34 and 35 Kg. The body is also aerodynamic with a relatively small round head, and a narrow body, elongated to fit its large respiratory system usually measuring between 112 -135 cm. This light weight body does pose a couple of problems; traction and balance. For traction the cheetah has adapted special paws, the scientific name of the cheetah is 'Acinonyx Jabatus', the genus name of 'Acinonyx' is interpreted as non-moving claws, which refers to the fact that unlike all other cats a cheetahs claws are only partly retractable, and so act much like the spikes on a sprinters running shoe, furthermore the dog-like elongated pads on the paw offer more traction than the traditional rounded pads of other cats. However, whilst in full 'flight' these paws have minimal contact with the ground, so the tail measuring a massive 66-84cm (two-thirds of the body) not only acts as an effective counter-balance but also has a flattened tip acting like a rudder to guide direction.

While all these elements make the cheetah the fastest land dwelling animal such extreme speed has come at a cost. Whenever a cheetah runs it seriously risks over-heating and starving its brain of oxygen, both of which can cause brain damage and even death. Furthermore the light weight build of the cheetah leaves it susceptible to attack, and losing its prey to other large predators such as lion or even baboon. To counter this problem the cheetah has developed a habit of hunting when it is both cool and when other predators are less active. The last feature of the cheetah that allows it to fully utilize it's speed are it's eyes, the golden eyes of the cheetah are perfectly adapted to take advantage of the poor quality of light during dawn and dusk, when it is both cool and when it can best avoid other predators.



References

The Encyclopedia of Animal Biology: Professor R. McNeill Alexander, Equinox (Oxford) Ltd, 1987

Ultimate Killers: Steve Leonard, Boxtree, 2001

More about this author: William J. Stevens

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