They resemble small, furry rats in their body shape, but their long hind legs make them look like miniature kangaroos. There are over 80 species of gerbil. Many are named for their appearance, such as the fat sand mouse and the fat-tailed gerbil. The largest gerbil, the Great Gerbil, has thick fur and a short tail. It looks the most similar to a rat.
Gerbils are social animals that often live in large communities.
A gerbil's burrow is usually part of an interconnecting system with many entrances and separate chambers for nesting, sleeping, and storing food. To live in hot, dry areas, gerbils minimize their water loss. Their digestive systems extract water from food and their kidneys reabsorb water from their urine. Gerbils also have specially adapted bones in their noses that condense water vapor from the air before the animal breathes out. In this way, essential moisture is retained.