Lemurs use concealment and camouflage to protect themselves. They also have prodigious leaping ability to flee from predators. When in groups, they watch and listen and alert each other with different warning calls for diverse predators such as mammals, snakes and birds. They also listen for the alarm calls of nearby non-predatory birds.
Some species of lemur forage alone at night to make themselves more invisible and difficult to track. They also alternate sleeping sites to confuse predators and conceal themselves in thick vegetation, holes in trees or nests. Lemurs have an excellent sense of smell and avoid areas where they detect the feces of predators. When adults are foraging, infants are hidden in nests or foliage, where they remain immobile until parents return. Lemurs that are daytime foragers, such as the ring-tailed lemur, live in large groups with elaborate social systems. Complex vocalizations signal not only danger, but also a wide range of other auditory communications. The colors of their fur and the dappled light of the sun in the trees create the natural camouflage which has caused lemurs to be known as ghosts of the forest.
Lemurs live only on the island of Madagascar off the coast of southeast Africa, and several species are listed by the International Union for Conservation of Nature as either critically endangered or endangered. The main reason is habitat loss due to human encroachment and the diminution of rainforests.