Laurie Lederman, age 12, of Staten Island, N.Y., for her question:

WHAT IS A SPIDER MONKEY?

A spider monkey isn't a spider. It is a large monkey that is noted for using its tail as an extra limb. It can hang by its tail and even pick up objects by curling its tail around them. The monkey resembles a huge spider when it hangs upside down from a tree limb, with all four of its legs extended. Spider monkeys can be found in the Western Hemisphere from central Mexico to central Bolivia. They live in groups up to 100 monkeys and spend most of their time in high branches.

Spider monkeys, unlike almost all other monkeys, have only four fingers and no thumb. An adult weighs from 10 to 15 pounds and grows to be about two feet long, not including a very long tail. It lives"on fruits and nuts.