why man not having tail but animal have?

Most animals use their tails for movement. Sea creatures use theirs directly as a rudder, like a boat. Land animals often use them to balance when running or jumping, which allows them to balance, change direction etc better. Because we walk on 2 legs, we have no need for a tail and it would just get in the way. Apes like gorillas and chimps have no tail. We do have the remainder of a tail (or a sign of where it used to be) at the base of our spine (coxix)