Proportion, a giraffe could bite its own toenails

Back on topic. Here is a photograph of a desert acacia, taken in Egypt. Source

[atsimg]http://files.abovetopsecret.com/images/member/d206a3d5fb30.jpg[/atsimg]
You will notice that while the crown of the tree is rounded and irregular above, below it is very regular - almost, in fact, a straight line.

When I first travelled in the Arabian desert, I noticed that the occasional tree one encountered was always shaped like this. Remarking upon it to my guides, I was told the cause: camels graze on the trees, which consequently have no foliage extending much below the average height of a camel's mouth above the ground.

I think this picture illustrates rather well why giraffes evolved long necks.