The idea that the Giraffe got it’s long neck due to food shortages in the lower reaches of trees seems like a no brainer. The Giraffe is taller than all other mammals and so can feed on the leaves that no other animal can reach. For this reason it’s neck has grown longer and longer. It was called Competitive Advantage. That is the conclusion that evolutionists like Lamarck and Darwin came up with. That is the story that children’s books tell and textbooks teach. But is this the truth…
1. If there was a drought it would be silly to assume only the higher branches are available for grazing. If this were the case then a multitude of antelope species in Africa would have gone extinct, or may not even have evolved in the first place.
2. As Pincher said back in 1949 “Males are nearly a meter taller than females, let alone young giraffes. The moment this sexual dimorphism was expressed in the evolution of the Giraffe, it would have been the males that could have reached the higher branches. The females and young animals would have died and the species would have gone extinct.”
3. Researchers have spent hours watching Giraffe feed and can confirm that the majority of the time they are only feeding at shoulder height.
4. There are other ways to reach the high foliage of trees. Goats, for example, are known to climb into trees and eat foliage. If feeding at such great heights is such a factor than surely we would have tree climbing leaf-eaters in the savannah.
Could the evolution of the Giraffe’s neck not be linked to something else…
Again it was Pincher (1949) who queried Darwin saying that the “most extraordinary feature of the Giraffe is not the length of the neck but the length of the forelegs.” By developing long legs, the Giraffe has acquired a huge stride so that it can move relatively fast for its size. This has left the giraffe with only one predator—the lion. Is it maybe possible that the Giraffe developed long legs and quite simply the neck had to follow suite as as to enable the Giraffe to drink water!
Simmons and Scheepers (1996) found flaws in this argument when they analysed 100 Lion – Giraffe kills. They found that almost twice as many bulls were killed as cows. Thus it did not pay to be a male with a longer stride. Another theory with a pitfall.
Simmons and Scheepers have more recently come up with another theory. That of sexual selection. They describe how male Giraffe fight by clubbing opponents with their large, massive heads; “the neck plays the role of a muscular handle. The largest (longest-necked) males are dominant among other male Giraffes and mate more frequently. Since long-necked males mate more frequently, selection works in favor of long necks.” But whilst this hypothesis explains the maintenance of the long neck it does not explain the origin of the long neck, nor does it explain the female’s extended neck as they do not ‘club’ each other.
So far all these hypotheses have flaws… Perhaps looking for one reasoning is the problem. Remember the neck has a number of functions. It allows feeding from high branches, serves as a weapon in males, brings the head to elevated heights that give the Giraffe a large field of view, is used as a pendulum while galloping, and so on.
To play devils advocate I am on the side that says that Giraffe’s have short necks! If you watch a Giraffe drink you will see how they have to either splay their forelegs to the side or bend their forelegs strongly at the wrist joint. This is a very akward movement for a Giraffe and hence they are always extremely cautious in doing so. When one looks at the Giraffe from a drinking perspective, the Giraffe has a very short neck. Antelopes and zebras reach the ground without bending their legs, and the long-legged elephant has its trunk to compensate for its short neck. Only the Giraffe (and its rain forest relative, the Okapi) have necks that are so short relative to their legs and chest that they must splay or bend their legs.
So why has the Giraffe not become famous for it’s short neck? I guess it all depends on the perspective from which you view the animal. We are always amazed at the long neck as it towers skywards…we forget certain other elements of the animal and forget that when exploring the evolution of an animal we must take a holistic approach.
Written by Adam Bannister ; inspired by an article by Craig Holdrege
Filmed and photographed by Adam Bannister
Pincher, Chapman (1949). “Evolution of the Giraffe,” Nature vol. 164, pp. 29-30
Simmons, Robert, and Lue Scheepers (1996). “Winning by a Neck: Sexual Selection in the Evolution of the Giraffe,” The American Naturalist vol. 148, pp. 771-786.