Kiran K Karthikeyan wrote:
*For centuries experts have argued over how the giraffe got its long neck.*
While the above is an interesting question, I find a much more interesting question is: "Why does the giraffe have such a *short* neck?" There are only two quadripeds who have such great difficulty in placing their mouth below their feet as is required to drink from a pond or stream without getting in it; the giraffe and the elephant (and the latter have evolved an alternative method of drinking and eating low food). Watch film of a giraffe getting a drink and you'll notice how difficult that task is for them The argument that height offers sexual advantage makes some sense, but it doesn't explain why the neck hasn't kept pace with the legs. Neither does the high grazing explanation explain the discrepancy. One might suppose that the neck length has been maxed out based on blood supply, and the legs ran just a bit longer before being stopped by impracticality, but given the giraffe's remarkable heart, normal blood pressure, and the unique blood vessel design in the neck, it seems hard to credit that some absolute limit has been reached there. Body design is a balancing act. Height vs speed, weaponry vs biological cost, social structure vs depletion of local food, etc. It would seem that the giraffe, unique among animals past or present, has evolved into a peculiarity not seen elsewhere. And I'd like to understand why. I believe it was Steve Talbott of the Nature Institute who first brought this to my attention. I'd offer a citation, but I'm presently at sea and don't have access to my library, sorry. Bruce
