Jon Brahn, age 12, of Fargo, N.D., for his question:

HOW BIG DOES A KANGAROO RAT BECOME?

The kangaroo rat is a small animal that jumps around like a kangaroo on long, powerful hind legs. The creature grows to be only about 15 inches long, including a tail of about eight inches.

Kangaroo rats live in the deserts of the Southwestern United States. They nest in burrows or tunnels and come out at night to gather plant food. They use their small front feet to stuff food into fur lined pouches on the outside of their cheeks. They carry the food back to their nests.

The small animals have large heads and big eyes. Their silky fur is yellow or brown on the upper parts and white on the underparts.

Kangaroo rats, like their relatives the pocket mice, do not need to drink water. They use the water that is produced when food inside them combines with the oxygen they breathe.

Kangaroo rats are rodents and are related to squirrels, mice and rats. They look like jerboas, which live in African and Asian deserts.