Lemurs are found naturally only on the island of Madagascar and some smaller surrounding islands, including the Comoros (where it is likely they were introduced by humans). Fossil evidence indicates that they made their way across the ocean after Madagascar broke away from the continent of Africa.  While their ancestors were displaced in the rest of the world by monkeys, apes, and other primates, the lemurs were safe from competition on Madagascar and differentiated into a number of species. These range in size from the tiny Pygmy mouse lemur to the 22-pound Indri. Typically, smaller lemurs are active at night (nocturnal), while larger ones are active during the day (diurnal).

They are generally omnivores, eating a variety of fruits, flowers and leaves (and sometimes nectar) as well as insects, spiders, and small vertebrates. 

Lemurs have opposable thumbs and long grasping toes, but their tails are not prehensile. Lemurs have nails rather than claws. All lemur species have a tapetum, the reflective layer over the retina. Lemurs are thought to have limited color vision, and as such, they depend quite heavily on the sense of smell and have large nasal cavities and moist noses.

Unlike most other primates, lemur species that live in groups have a matriarchal society (i.e. females are dominant over males). Most lemur species are primarily arboreal and traverse the canopy by vertical clinging and leaping or quadrupedalism. However, the Ring-tailed lemurs shown here, spend a considerable amount of time moving about on the ground.