(potto)
Potto (Perodictus potto) (photo by David Haring)

Lorises, Pottos, Galagos (Bush Babies) & Tarsiers


Introduction

All of these animals (along with lemurs) are generally referred to as "prosimians". They are all primates, but only distantly related to monkeys and apes. They are tiny to small animals only reaching a weight in the largest species of about 1.2 kg (2.6 lbs). All are entirely arboreal and nocturnal. None live in Madagascar. Lorises live in India and Southeast Asia; Pottos and galagos live only in Africa; tarsiers are found only on certain islands in Malaysia.

Lorises, pottos, and galagos are closely related to lemurs; tarsiers are only distantly related. Lorises, pottos and galagos all belong to the family Lorisidae. Tarsiers belong to the family Tarsiidae and an entirely different superfamily, the Tarsiodea.

The Duke Primate Center has the most experience with lorises and the least with tarsiers among this group of animals. Because they are nocturnal and small, the lorises, pottos, and galagos in the Duke collection are housed in the Nocturnal Building where the day/night cycle is artificially controlled. This allows study of the animals by researchers during normal working hours and lets Duke control the length of the days to mimic conditions in their native habitats.

As of April 1996, Duke had the following lorises, pottos, and galagos in its collection:

How Lorises, Pottos, Galagos & Tarsiers Differ from Lemurs and Monkeys

From an evolutionary perspective, the most important difference between these animals is the length of time they have evolved on their independent path. From that perspective, several scientists have recently concluded that tarsiers should be classified in their own superfamily, Tarsiodea, separate from both monkeys and apes (superfamily Anthropoidea) and lemurs, lorises and galagos (superfamily Lorisoidea).

The lorises, pottos and galagos, like lemurs, can be distinguished from monkeys and apes (and tarsiers) by having a moist snout and having a face covered with hair.


Lorises and Pottos (subfamily Lorisinae)

Lorises and pottos are slow movers. They have been described as moving like "slow and cautious bear cubs". Their movement has also been described as chameleon-like. This slow, smooth movement makes them very hard to detect in the thick vegetation where they are found. They have lost the skills of leaping that are so well developed in galagos and lemurs.

Lorises

There are three species of lorises. All three species live in Asia. Their common name "loris" is derived from the Dutch word for "clown", and these animals received the name for their often comical postures. Lorieses can freeze motionless for very long periods. They locate their prey principally by smell, although their large eyes and binocular vision. Lorises

Slender Loris (Loris tardigradus)

The slender loris is found in tropical forests where they remain India and Sri Lanka. It is a relatively small primate reaching a head and body length of 24 cm (10 inches) and a weight of about 300 grams (about 9 oz.). Slender lorises have no tail. It is quite slender and is recognizable by large black spots surrounding each eye separated by a narrow white line down to the nose.

Slow Loris (Nycticebus coucang)

The slow loris is found from Bangladesh to Vietnam, and also in Malaysia, Sumatra, Java, and Borneo. It is a bigger and more robust than the slender loris.

The slow loris has a well-developed gland on the inner surface of its forearm which produces a thick secretion that is toxic! The slow loris spreads this secretion on its back when rolling up in a defensive posture with arms extended above their heads. _______ University professor Lon Alterman states that the active ingredient of this secretion is so toxic that a taste of only a small amount will send a human into shock. Alterman presented a small cotton swab of this to a sun bear, a potential predator of lorises, which immediately ran to the opposite end of its enclosure.

The slow loris makes many different sounds including grunts, growls, chirps and whistles, some of these at ultrasonic frequencies. The slow loris also use urine and other glandular secretions to mark their territories.

Pygmy Slow Loris (Nycticebus pygmaeus)(pygmy loris)

The species is found in Indochina, and is similar enough to the slow loris that some scientists consider it to be just a subspecies of the latter.

Pottos

There are three species of pottos. All three live in Africa. They feed on irritant caterpillars, foul-smelling beetles and poisonous millipedes. These prey are generally avoided by the faster-moving galagos. The difference in the diets of these two groups of prosimians allows them to coexist in the same forests.

Potto (Perodicticus potto)

The potto is found in tropical forests of the west African coast from Guineau to the Congo and from Gabon to western Kenya. It has a head-body length of 32 cm (12 inches) with a 5 cm tail (2 inches) and weighs about 1 kilogram (2.2 pounds).

Like the slow loris, the potto also has a toxic glandular secretion. Prof. Alterman exposed an African palm civet, a potto predator, to this secretion and the civet "let out a scream that was audible from several hundred meters." Female pottos use this deterrent by coating their young with it, parking them on a branch overnight, while the females go out foraging.

Pottos have an additional adaptation against predators. The nape and back of the potto has thickened skin which overlie modified spinal processes on their vertebrae which project through the shoulder blades and create a "shield". Charles-Dominique writes:

"The 'shield' is covered by fur and tactile hairs 5-10 cm (2-4 in) long which detect any attack. In the event of an attack by, for example, an African palm civet, the potto turns toward it, head buried between its hands and presenting its shield. The aggressor's charges are dodged by sideways movements without the potto loosening the grip of its hands and feet on the branch. Then, straightening its body, and maintaining a clamp-like hold on the branch, the potto delivers fearful bites or a violent blow with its shield, toppling the predator to the ground, where it is difficult for the aggresssor to find a route back to its prey."

Angwantibo or Golden Potto Arctocebus calabarensis

The Angwantibo is found in a very limited areas of equatorial west Africa in southern Nigeria, souther Cameroon, Gabon, Congo, and western Zaire. This species is more slender and light compared to the potto being only 24 cm long (10 inches) with a very short tail.

The Angwantibo has an unusual and remarkable diet mainly of caterpillars which have irritants in their hairs. They attempt to rub off many of the hairs before eating the caterpillar. Given a choice, the Angwantibo will select less difficult food, but in the competitive environment of the rain forests the slow-moving caterpillars are avoided by other species and hence, relatively available to the Angwantibos.

____ Potto (no common name) Arctocebus aureus

This species is smaller than the Angwantibo and occupies the southern part of the range described above for the Angwantibo.


Galagos (Bush Babies) (subfamily Galaginae)

Scientists generally refer to this group of small and mid-sized prosimians as Galagos, after the scientific name of one of the better-known species. However, many of them were popularly named "bush babies" years ago because of the infant-like screams and that name appears often in both the scientific and popular literature. Galagos have long, furred tails, big eyes and large ears they can move independently.

Galagos occur in rain forest and woodland savanna throughout sub-Saharan Africa. Active at night, they feed on insects, fruit and tree gum. Galagos range in size from mouse-sized animals to animals the size of a small cat.

Recent research into the vocalizations and ecology of galagos has resvealed that there are far more species of galagos than previously thought. For example, the 1984 Encyclopedia of Mammals describes only six species of galagos. In his 1995 Natural History article listed below, Simon Bearder refers to 16 known species and "a suspicion that there may be as many as forty." Accordingly, the following should be considered a very tentative start on the list of galagos!


Tarsiers

Tarsiers are particularly interesting since they appear to be intermediate between the lemurs and monkeys, being classified in their own superfamily, "Tarsiodea". They are small, ranging from 9-15 cm (4-6 inches) in head-body length with thin tails about the same length as their body with a tuft of fur at the tip. Proportionally, they have much longer rear legs than other prosimians, their rear legs being about twice as long as their head-body length. The species are:

The three species of tarsiers are found separately only on a few large islands in southeast Asia. They are crepuscular (active at dawn and dusk) and nocturnal and found in rain forest and shrub habitats. In contrast to most lemurs, tarsiers are almost exclusively insectivorous and carnivorous. They feed on ants, beetles, cockroaches, scorpions, birds, and sometimes snakes. Lizards and bats are also taken by some individuals.

Tarsiers use their very long legs to leap from branch to branch. They catch prey hearing it with their large ears, then leaping at it, pinning it down with one or both hands, and killing it with one or more bites with their needle-sharp teeth. Their leaping in poor light or darkness is made possible by their binocular vision and their enormous eyes. In the Western tarsier, each eye alone weighs more than their brain!

Where to See Lorises, Pottos, Galagos & Tarsiers in Captivity

If you want to know where you can see these species in captivity, check out our Captive Prosimians by Species page. This provides links to the International Species Information System (ISIS) with information from zoos around the world.

Suggested Readings


Updated September 25, 1996