Why don't Humans and other Great Apes have tailbones?

i have a pretty logical and rational mind, and to me the idea of god is a little off, and so is evolution. i would say it's a little bit of both, but maybe you should open your eyes to what god actually means. i think it could be a lot different than we have previously thought.

Originally posted by articulus
As the wiki article DeltaChaos mentioned, people do occasionally sprout tails, thanks to little hiccups in the genome. There was an exceptionally weird X-Files episode that dealt with this, if you can find it. I can't recall any plot details, other than it was one of the finer "stand-alone" episodes that didn't deal with the alien/government conspiracy. I, for one, am glad we've long since abandoned unnecessary appendages. In a few million years, perhaps we'll have ditched our pinky toes as well, or at least that irritating little nail that's always so tricky to clip.

They are called atavisms.

Atavism
n. 1. The reappearance of a characteristic in an organism after several generations of absence, usually caused by the chance recombination of genes.

I think whales with legs is the most famous ones.
animals.howstuffworks.com...

Multiple Boob Syndrome is another one found in humans at times
en.wikipedia.org...
en.wikipedia.org...