Tarsiers are primates (a group including lemurs, monkeys, apes and humans) found only in the islands of Southeast Asia. There is debate among scientists over how many types of Tarsier exist and whether there are more yet to be described. Most recently it was thought that there are 3 species groups (or genera): Western, Eastern and Philippine, with 18 species and subspecies in total belonging to these 3 groups. There are many differences between species, including eye size, ear size, behavior, vocalizations and distribution.
Tarsiers are arboreal (tree living) and jump through the trees to catch their food, which is mainly insect based, although can include lizards, snakes and birds. Tarsiers are small with very large eyes, elongated hind legs and feet, a thin tail and long fingers. They are nocturnal (active at night) although some species may move around in the daytime. Some species live in family groups while others spend most of their time alone and mating behavior also varies between species. Tarsiers are born with fur and their eyes open and can climb trees within an hour of birth.
The majority of Tarsier species are now endangered or threatened, and some are designated critically endangered. Threats include habitat destruction and fragmentation, hunting, agricultural pollutants and human disturbance. Tarsiers are very shy animals that prefer to stay away from human contact. Tarsiers do not live well in captivity – they have specific feeding requirements which are difficult to meet and rarely successfully breed. Wild Tarsiers which are caught and kept in captivity only show around a 50% rate of survival and in many cases they die quickly of overstress by committing “suicide”.
Some conservation efforts are under way for the various species, most notably the Philippine Tarsier. Conservation efforts should focus on their wild populations and habitats.
Tarsiers are ‘haplorrhine’ primates - a group which also includes old world and new world monkeys and apes (including humans), but not lemurs, aye-aye or lorises. The haplorrhines cannot manufacture their own vitamin C, have a large range of facial expressions and their primary sense is vision. ‘Haplorrhine’ translates as “dry-nosed” or “simple-nosed” primate.
Originally it was thought that all Tarsiers belonged to the same Genus Tarsius and there were ten species present within this grouping. There was some confusion over which species were most closely related and whether some were separate species or actually subspecies. It can be difficult to classify Tarsiers and often vocalizations were used rather than morphology (appearance) while very little was known about some of the more isolated populations. In 2010 it was proposed that the Tarsius genus should be split into three to reflect the differences between the species in terms of appearance, vocalizations, social structure and distribution. This classification included a number of newly found species, bringing the number up to 18 named species in 2011.
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Philippine tarsier in the wild. © Pierre Fidenci
A spectral tarsier. © Paddy Ryan