Balls. Even a simple rubber ball can enrich a caged nonhuman primate's environment. These balls are inexpensive (usually less than $10) and are available in a variety of colors and sizes.

This figure does not include the 41,348 primates who were not assigned to research but were instead part of laboratories' breeding colonies. Primate species in research include rhesus macaques, ...

This is a rarity in primate research, and illustrates just how much remains to be known about these fascinating animals. Like all lemurs, mouse lemurs inhabit the island of Madagascar off the east ...