Night monkeys

Night monkeys are nocturnal New World monkeys that are found in forests across Panama and much of South America. Night monkeys have large eyes which improve their vision at night, while their ears are mostly hidden, giving them their name Aotus, meaning "earless". They have a varied repertoire of vocalizations and live in small family groups of a mated pair and their immature offspring. These family groups are territorial and defend territories by vocal calls and scent marking. During the daylight hours, night monkeys rest in shaded tree areas. These sleeping sites provide protection from heavy rains, sunlight, and heat. Night monkeys are threatened by habitat loss, the pet trade, hunting for bushmeat, and by biomedical research. Use in biomedical research poses another threat to the night monkey biodiversity as they constitute one of the few monkey species that are affected by the often deadly human malaria. Up to 2008, more than 76 night monkeys died as a result of vaccine testing, some died from malaria, while others perished due to medical complications from the testing.