Good question. This is one I answered before:
“I think it would be really cool to have a tail
that could grab onto things (a prehensile
tail). Unfortunately, humans and our closest
relatives (the apes) don't. We do have what's
called a "vestigial" tail, meaning that
it's a sort of evolutionary leftover. It's visible
in embryos, but by the time we're born, we just
have a few small bones that can't be seen from the
outside. Most people don't even know they have
tailbones unless they break one. Occasionally, a
baby will be born with a tail, but it is usually
Why did the ancestor of the apes and people
lose their tails? No one really knows.
Things don't disappear just because they are not
being used. One gene can cause many different
things. It is possible that a gene that was
helpful to this species had a few effects,
including the loss of the tail. It is also
possible that having a tail came with a price.
Individuals that had small or no tails would have
been able to leave more offspring with the no-tail
gene. Can you think of any ways that a tail
might be a problem?
People often confuse apes (chimps, gorillas,
orangutans, gibbons, etc.) with monkeys. They're
not. Apes don't have tails.”
I would also add that monkeys in the Americas
have prehensile tails, but the monkeys in Africa
don’t. Some can’t really grab with them at all.
Others can sort of hold onto things, but can’t
really grip them and can’t hang from them.
If you’re interested in questions like this,
there are all sorts of scientists that study this
kind of question. Developmental biologists
study how things form before they are born (or
hatched, or whatever). Evolutionary
biologists try to figure out how species ended
up the way they did. Anthropologists study
Thanks for asking,