Most hamsters are strictly solitary. If housed together, acute stress may occur, and they may fight, sometimes fatally. Gerbils, on the other hand, are social animals, and live in groups in the wild.

The giant pouched rats (genus Cricetomys) of sub-Saharan Africa are much better at detecting TNT than people or dogs. While they are far larger than many other rat species, they are still small enough and light enough that they don't trigger mines if they walk over them. The rats are trained to detect a chemical compound within the explosives, meaning they ignore scrap metal and can search for mines more quickly. Once they find an explosive, they scratch the top to alert their human co-workers.

The average glide of a northern flying squirrel (Glaucomys sabrinusis) is about 65 feet (20 meters), according to the University of Michigan Museum of Zoology, or slightly longer than a bowling lane. But it can go much farther if needed, with glides recorded up to 295 feet (90 meters).

A squirrel may use its tail as a shield when fighting, as a blanket in cold weather, and, sometimes, as an umbrella during rain storms.

Domelike beaver homes, called lodges, are constructed of branches and mud. In order to protect themselves from predators, beavers strategically locate their lodges in the middle of ponds and make them accessible only by underwater entrances.

In nature, chinchillas live in social groups that resemble colonies, but are properly called herds. Herd sizes can range from 14 members up to 100, this is both for social interaction as well as protection from predators.

These rats have been trained to detect tuberculosis, a highly infectious disease that public-health facilities often miss. They can screen 100 mucus samples in 20 minutes--a job that would take clinics four days. According to the Belgian organization APOPO, rats have boosted TB detection by 40 percent at the clinics where they are used.

Gerbil epilepsy, sometimes called fits, is a common condition seen in 20% to 40% of all gerbils. The seizures are thought to be caused by fright, handling, or a new environment.

All species of spiny mice are capable of autotomic release of skin upon being captured by a predator. To date, spiny mice are the only mammals known to do so. They can completely regenerate the autotomically released skin tissue, regrowing hair follicles, skin, sweat glands, fur and cartilage with little or no scarring.

Lemming behavior and appearance are markedly different from those of other rodents, which are inconspicuously colored and try to conceal themselves from their predators. Lemmings, by contrast, are conspicuously colored and behave aggressively toward predators, even sometimes attacking humans.