Overview
The Pygmy Tarsier (Tarsius pumilus), also known as the Mountain Tarsier, is the smallest, rarest, and most high-altitude tarsier on the planet. Barely larger than a tennis ball and weighing less than two ounces, this diminutive nocturnal primate was believed to have vanished into extinction in the early 20th century before its sensational rediscovery by Indonesian and American scientists in 2008 on Mount Rorekatimbo. Adapted to the damp, chilly cloud forests of Sulawesi, it possesses specialized pointed claws on all digits for clinging to wet, slippery moss-covered trees.
Biology and Physical Characteristics
Tarsius pumilus is a miniature haplorhine primate with extraordinarily specialized morphology. Its body is covered in dense, silky, red-brown or greyish-ochre fur that traps body heat in cold mountain cloud forests. Its colossal, saucer-like golden eyes are larger than its brain and fixed immovably in their orbits, compensated by a specialized neck joint capable of rotating nearly 180 degrees in either direction. Its elongated hindlimbs feature fused tibia-fibula bones and enlarged ankle (tarsus) bones that function like biological springs, allowing it to leap over forty times its body length. Unlike lowland tarsiers that have flat nails, the Pygmy Tarsier has evolved sharp, pointed claws on all digits to grip slippery mountain moss.
Behavior and Ecology
Exclusively nocturnal and solitary or pair-living, the Pygmy Tarsier hunts with extreme stealth through the dense understory of mossy cloud forests. It perches upright on slender vertical stems, rotating its head to scan for the faint rustle of insects with its highly mobile, membranous ears. When prey is detected, it launches with explosive speed, trapping the insect against the bark with both hands before devouring it headfirst. Recent bioacoustic studies reveal that it vocalizes primarily in the ultrasonic spectrum above 20 kHz, communicating in sound waves completely inaudible to human ears and predatory owls.
Conservation and Human Impact
The Pygmy Tarsier is classified as Endangered on the IUCN Red List. Due to its strict physiological restriction to cold, humid mossy cloud forests above 1,800 meters, it is acutely vulnerable to climate change-induced temperature rises, which push cloud base levels higher up isolated volcanic summits. Commercial conversion of lower mountain slopes for agriculture and illegal harvesting of timber trees also threaten to fragment its tiny high-elevation sanctuary.
Interesting Factoid
The Pygmy Tarsier weighs less than two ounces, has eyes bigger than its brain, can turn its head completely backwards like an owl, and talks to its family in pure ultrasonic frequencies that human ears cannot hear.