I’ve spent a lot of time in my graduate career learning about rodents. You see, every project we do in our classes is supposed to relate to the species our research project is on. So because I work with mice, every single presentation, essay, and project I’ve done in the past year has had something to do with mice. So you’d think by now I’d be thoroughly sick of mice and all their lovely rodent relatives. Fortunately, this is not the case! In fact, at a talk earlier this semester about field research in Mongolia, jerboas were mentioned, and I was instantly curious. So after checking them out in my handy Encyclopedia of Mammals, I decided these guys would make an excellent blog post.
Jerboas are members of the family Dipodidae, which also includes jumping mice and birchmice. Dipodidae are well known for their ability to jump, and in fact all members of the family travel by leaping around. The jerboa, however, takes jumping to another level. Just by looking at the skeleton of this rodent you can tell there is something weird about it.
Basically, jerboas are built like kangaroos. They use their ridiculously large hind legs for locomotion and their tail for balance. The forelegs aren’t used at all when moving; jerboas use the tiny limbs for gathering food. But trust me, jerboas don’t need their front legs to move. Their hind legs are specially designed for jumping power, with three foot bones fused to provide extra strength, and enormous size (they are over four times the size of the front limbs). Species that live in sandy areas have tufts of fur on the bottoms of their feet to give them traction (much like snowshoes do in snow). The result of these adaptations is that jerboas can jump an astounding 10 feet while moving quickly, and can jump 3 feet vertically. Not bad for an animal that doesn’t get bigger than ten inches.
Many jerboas live in sandy and arid habitats, and they have special adaptations to deal with these harsh environments. I’ve already mentioned the fur on the bottom of the hind feet, but some jerboas also have hair that covers their ears to protect them from sand. Some species also have a flap of skin that covers their noses while they burrow. To avoid the heat, jerboas are nocturnal, and spend most of the hot desert day inside burrows. Jerboas can have up to four types of burrow: temporary summer burrows, temporary winter burrows, permanent summer burrows and permanent winter burrows. Temporary burrows are used to escape predators and are usually simple, consisting of only one tunnel. Permanent burrows are much more complex, and can have a number of different chambers and be over 6 feet deep.
Jerboas mostly eat seeds and any desert plants they can find. One species eats mainly beetles and beetle larvae, but the majority of other jerboa species are herbivorous. Jerboas don’t have to drink to survive, as all their water needs come from their diet. You can imagine how useful that trait is in a desert.
Despite their somewhat silly appearance (especially the long-eared jerboa, I just can’t get over how weird that one looks), jerboas are really cool animals. So you see, rodents are awesome (I just kind of wish I could study jerboas)!