Zoology

Why Giraffes have Long Necks



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The Giraffe is the tallest living animal on earth and live in herds on the tree scattered Savannah or in scant woodland of Africa, keeping well away from the deep forest. Their long necks give them a huge advantage in spotting predators such as lions. Males can reach a height of over 5.5 meters and the female just under 5 meters.

Giraffes are vegetarians and use their immense tongues to wrap around the high foliage in trees, tightly grasping the greenery and stripping it from the branch. The Giraffes long neck and height help it to reach the succulent foliage that is just out of the reach of other animals.

Strangely enough the primitive giraffes which lived about 16 million years ago did not have the elongated necks. They looked more like the Okapi which is the second creature grouped in the family of Giraffidae. In fact the Okapi is really the typical or normal' member of the Giraffe family. They are shy, retiring creatures with normal sized necks but still sporting some of the Giraffes characteristics such as the horns. Nothing was known of them up until the year 1900 when their importance to the long necked Giraffe was discovered.

Throughout the ages, climatic changes on the Earth meant that access to food became more and more difficult for some animals. Some members of the giraffe family found that by stretching their neck just that little bit further, they could reach an abundance of food that mean that they never needed to go hungry ever again.

Although it has not been proved for certain why the giraffe has ended up with such a long neck , scientists such as Pincher (1949), suggested that the "most extraordinary feature of the giraffe is not the length of the neck but the length of the forelegs." He meant that the giraffes legs evolved over a period of time as a flight response to its only predator, the lion, and that the neck became lengthened so that the giraffe would still be able to feed and drink. Brownlee (1963) also thorised that it had happened in conjunction with the lengthening of the limbs, giving the giraffe a larger surface area which enabled it to dissipate heat much more effectively.

A more recent proposal comes from Simmons and Scheepers (1996) who believed that the lengtheneing of the neck was due to the process of sexual selection. They highlighted the fact that male giraffes will fight for dominance by using their huge heads as clubs and the 'winners' will mate more often and produce more offspring with the longer necks. They draw attention to the fact that not only do the giraffes have long necks, the males also have heavier heads than the females. 

Charles Darwin also argued that due to the plentiful food supply the Giraffe grew huge in statue and needed to keep eating lots of food to sustain its huge bulk. The strongest of the giraffe survived by being able to stretch their necks the furthest and eat the foliage that other animals couldn't get to. Eventually the only giraffes that survived were the ones that could reach the food. The shorter necked giraffes died out. Through the process of natural selection, the giraffes long neck evolved over millions of years until eventually, it became totally unlike its original ancestors. It can now be compared to the Okapai as an oddity of the family, who survived the evolution with relatively few changes.



Sources: MSN Encarta
The New Illustrated Animal Kingdom Mammals vol.7 Odhams Books (1962)




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