The naked mole-rats are huge with the kids

KNOXVILLE, Tenn. —

Inside a small clear tube, a naked mole-rat decides to change direction. Contorting its wrinkled, hot dog-shaped body, the animal nearly somersaults over itself and pokes out its head on the other side. It shows off four big teeth, sniffs the air and turns around again.

Watch a naked mole-rat for a while, and you'll see this happen over and over and over. It's the nonstop movement and unusual characteristics — certainly not its beauty — that make mole-rats a hit with zoo visitors, especially children.

Natives of Africa, naked mole-rats are the only eusocial mammals, meaning they live in a colony ruled by a queen, the only female who reproduces.

In the wild, they spend nearly all their time underground, but despite their name they are neither moles nor rats. Mole-rats are more closely related to chinchillas, guinea pigs and porcupines.

There are several species of mole-rats, but only naked mole-rats are, well, naked or nearly hairless. Some other types of mole-rats are not eusocial and live alone or in smaller groups.

Naked mole-rats are about 3 to 4 inches long and can look — to put it politely — downright homely in large up-close photographs that emphasize their little-to-no hair, wrinkly skin and walrus-like teeth.

Zoos are spreading the critters to other zoos when their colonies grow too large and need to be split.

...very interesting, you learn something new every day.