98.76%

Photos like this remind me that the eight-year-old boy in me never really grew up. He has lots to say about these chimps. But the 'grown' man he has supposedly become will try to exert himself and come up with something worthwhile...

Though chimpanzees are 98.76% identical to humans genetically. The 1.34% difference results in denser bones (they shy away from water because they sink), tougher skin, a strength that is 5-7 times greater than humans (I am 0 and 3 in arm wrestling chimps), and redder, knobbier butts.

I'm no ape expert, but I'm guessing the chimp on the left is the male, and the one on the right is female. I'm also guessing it's mating season. Nothing sets the mood in Chimpland quite like a red rear end.

Photo source: Mark Ferbert