Reginald Ragin, age 12, of Charlotte. North Carolina, for his question:

Is the gerbil in the rat or kangaroo family?

The kangaroo is a marsupial, famous for using his long tail and two hind legs for hopping around. The gerbil is a mousy little fellow who has a long tail and also likes to hop around on his back legs. The two animals favor a similar mode of travel. Seeing them in motion, one might suspect that the tiny gerbil is a miniature cousin of the whopping kangaroo. However, the gerbil is not a pouched marsupial.

Actually, the furry little leaper is a member of the ratty rodent clan. The gerbils, alias the sand rats; are native to certain African and Asian deserts. Large colonies live in burrows. They come out to feed at night and store grain supplies underground. The fat tailed gerbil of North Africa, naturally, has a fat long tail. The fat is surplus food, which makes grain hoarding unnecessary. The gerbils belong in the sub family Gerbillinae, of the Order Rodentia.