Denise Wilcott, age 11, of St. Norbert, Manitoba, Canada, for her question:
WHAT IS A JERBOA?
There are so many different types of animals on earth that it is impossible to count them all. They come in every size and shape and can be found in every part of the world. Scientists have already classified about a million kinds of animals, but each year hundreds of new ones are discovered. Some are huge and some so small they can only be seen with a microscope.
One of the earth's interesting animals is called the jerboa. Can you imagine a creature that looks like a tiny kangaroo? He balances himself on his hind legs with the help of a long tail and jumps just like a kangaroo when he is frightened. But he's not a kangaroo. He's a rodent.
The jerboa is light yellowish brown in color and has buttonlike eyes, pointed ears and long whiskers. His front legs are short, and he usually walks along on his long, powerful hind legs. His body is only six to eight inches long.
Actually there are 25 different species of jerboas. You'll find them in the dry parts of Africa, Asia and Eastern Europe. Best known type is the Egyptian jerboa, and he is said to make an excellent pet.
You'll find the jerboa living in groups. They dig tunnels and come out at night to look for food. They select plants, seeds and insects to eat. In cold climates, some of them hibernate each winter.
The jerboa is very much like the kangaroo rat which you'll find living in the United States. They are so similar, as a matter of fact, that it is difficult to tell them apart. Yet study of their skulls and teeth show the two animals are quite different. Scientists point them out as an example of convergent evolution. Because both the jerboa and the kangaroo rat live in dry regions, similar features have developed in both animals.
The kangaroo rat can be found on the deserts of the southwestern part of the United States. He nests in burrows and comes out at night to get plant food. He has fur lined pouches on the outside of his cheeks into which he stuffs his food. He then carries his dinner back to his nest.
A kangaroo rat's eyes, like those of the jerboa, can see well in the dark. The North American creature is larger than his Asian and African look alike: he measures about 15 inches in length.
The kangaroo rat and the jerboa do not need drinking water. They obtain the water that is necessary to keep alive through the food they eat. Actually water is produced when food inside them combines with the oxygen they breathe.
The kangaroo rat has a relative called the pocket mouse.
The jerboa belongs to a family with the scientific classification of Dipodidae and the genus Dipus. The kangaroo rat's family is called Keteromyidae and his genus is Dipodomys.