The problem with being tall

Those of us who have grown-up watching Giraffe don't realise it, but they really are weird looking animals. Most of us have been told since childhood that the incredible height of a giraffe (up to 5.5m or 18 feet!) is an adaptation to allow it to reach food material beyond the reach of other browsers. Personally I'm not convinced that this was the driving selective force for that great height. I think that excellent vision combined with great height provide giraffe with their best predator-avoidance mechanism and it is this advantage...