The Giraffe's Short Neck: Why Evolutionary Thought Needs A ...

I sometimes wonder why no one has maintained that the giraffe has, in reality, a short neck. If you observe a giraffe drinking or, as they occasionally do, grazing close to the ground, then you know what I mean (see Figure 4). Giraffes do not drink often, but when they do, they have to either splay their forelegs to the side or bend their forelegs strongly at the wrist joint. Both procedures take time and are awkward for the giraffe. But only in this way can it get the tip of its mouth down to the surface of the water. So, looked at from the perspective of drinking, 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 hasn’t the giraffe become famous for its manifestly short neck? Why don’t we have evolutionary hypotheses explaining how the giraffe got its short neck? It is because the giraffe’s neck, in other respects or from other perspectives, is long. No other mammal has such a long neck in absolute terms or in relation to the length of its torso. We all have seen (in life or in pictures) and been amazed by the standing giraffe, its long neck sailing skyward, in comparison to which the ungainly, short-necked drinking giraffe appears as exceptional, almost unfortunate behavior.

Whether the neck is long or short depends on our perspective and on the behavioral or anatomical context we are focusing on. We only understand the giraffe when we view it from various perspectives and let the giraffe show different aspects of its being. The moment we focus solely on the “long neck” — and on it solely in terms of a food-gathering or some other strategy — we’ve lost the reality of the giraffe.

Reality is richer than such explanations. The explanation may be coherent and logical, but what it explains is not the thing itself but a specter of it — the isolated aspect that has been abstracted from the whole organism. In reality, the organism as a whole evolves; all its parts are multifunctional, facilitating its interactions with its complex, changing environment. If we don’t consider all partial aspects within this larger context, we can only have inadequate explanations void of life.

In sum: the whole project of explaining the evolution of an animal by abstracting from the whole leads to unsatisfying, speculative ideas on the one hand, and to conceptual dissolution of the unity of the organism on the other. A more adequate understanding requires that we first investigate the organism as a whole and how its members interrelate and interact within the context of the whole organism and its environment. This holistic understanding can then form the starting point for thinking about the evolution of the animal. The evolutionary biologist Dobzhansky’s famous statement that “nothing in biology can be understood except in light of evolution” is a grand claim, which I believe is, in the end, true. But we have a lot of work to do before we get there, and we should not be satisfied with short-cut evolutionary “explanations.” Another consequence of the usual way of explaining is that the organism itself is atomized into individual characteristics, each having its own explanation. Each part takes on a quasi-reality of its own, while the whole organism — which brings forth and gives coherence to the parts — degenerates into a kind of epiphenomenon, a mere composite of the surviving parts that “really” count.

If evolutionary thought is to have a solid foundation, we must establish this firm grounding in holistic understanding. As it is, stories of the evolution of traits seem compel-ling until you look for their context and foundation in the world and discover a pool of quicksand. As Simmons and Scheepers remark about Darwin's idea of giraffe evolution, “it may be no more than a tall story.”

* Assuming for the sake of explanation a spherical body, the two-dimensional surface grows as a function of the square of the radius, while the volume — being three-dimensional — grows as a function of the cube of the radius. A small sphere with a radius of 2.5 cm (1 inch) has a volume-to-surface ratio of 0.8:1. A much larger sphere with a radius of 50 cm (about 20 inches) has a volume-to-surface ration of 16.7:1.