Steve Cooper, age 9, of Columbus, Ohio, for his question:

WHY DO WE CALL THEM SPIDER MONKEYS?

A spider monkey is a large monkey noted for using its tail as an extra limb. This monkey sometimes hangs upside down, with all four limbs and its tail grasping branches. It resembles a huge spider in this position    and that's how it received its name.

Spider monkeys often use their arms and tails to swing from branch to branch. The tail can even be used to pick up objects by curling it around them.

Spider monkeys are found in the tropical forests of the Western Hemisphere, from central Mexico to central Bolivia. They live in groups from two to 100 monkeys and spend most of their time in high branches, where they eat nuts and fruit.

Adult spider monkeys weigh from 10 to 15 pounds and grow to be almost two feet long, not including the tail. Various species have black, brown, tan, reddish or golden fur.

Spider monkeys, unlike most other monkeys, have only four fingers and no thumb.