Potto

The potto (Perodicticus potto) is a strepsirrhine primate from the Lorisidae family. It is the only species in genus Perodicticus. The Potto is also known as Bosman's potto, after its supposed discoverer, and in some English-speaking parts of Africa it is called a softly-softly.

Subspecies
There are four recognized subspecies:
 * Perodicticus potto potto
 * Perodicticus potto edwardsi
 * Perodicticus potto ibeanus
 * Perodicticus potto stockleyi

However, variation among pottos is significant, and there may in fact be more than one species. A few closely related species also have "potto" in their name: the two golden potto species (also known as angwantibos) and the false potto. The false potto may in fact be the same species as the potto.

Habitat
Pottos inhabit the canopy of rain forests in tropical Africa, from Guinea to Kenya and Uganda into the north of the Democratic Republic of Congo. They are nocturnal and arboreal, sleeping during the day in the leaves and almost never descending from the trees.

Physiology
Pottos grow to a length of 30 to 40 cm with a short (3 to 10 cm) tail and their maximum weight is 1.5 kg. The close, woolly fur is grey brown. The index finger is vestigial, although they have opposable thumbs with which they grasp branches firmly. At the second toes of the hind legs they have the fine claw typical for strepsirrhines. Three of the vertebrae in the potto's neck have sharp points and nearly pierce the skin; these are used as defensive weapons. Both males and females have large scent glands under the tail (in females, the swelling created by the glands is known as a pseudo-scrotum), which they use to mark their territories and to reinforce pair bonds. Pottos have a distinct odor that some observers have likened to curry.

In potto hands and feet, fingers three and four are connected to each other by a slight skin fold, while toes three through five are joined at their bases by a skin web that extends to near the proximal third of the toes.

Locomotion and diet
Pottos move slowly and carefully, always gripping a branch with at least two limbs. They are also quiet creatures. Their most common call is a high-pitched 'tsic,' which is used mainly between mother and offspring.

Studies of stomach contents have shown that the potto diet consists of about 65% fruit, 21% tree gums and 10% insects. Pottos have also occasionally been known to catch bats and small birds. Their strong jaws enable them to eat fruits and lumps of dried gum that are too tough for other tree-dwellers. The insects they eat tend to have a strong smell, possibly because more palatable insects are snatched up by faster-moving creatures.

Territorial and reproductive behaviour
Pottos inhabit firm territories which they mark with urine and glandular secretions, and same-sex intruders are vehemently guarded against, although each male's territory generally overlaps with that of two or more females. Females have been known to donate part of their territories to their daughters, but sons leave their mother's territory upon maturity.

As part of their courting rituals, pottos often meet for bouts of mutual grooming. This is frequently performed while they hang upside down from a branch. Grooming consists of licking, combing fur with the grooming claw and teeth, and anointing with the scent glands. Pottos mate face-to-face while hanging upside down from a branch.

After a gestation of about 170 days the female gives birth. Births are typically of a single young, but twins are known to occur. The young first are clasped to the belly of the mother, but later she carries them on her back. She can also hide her young in the leaves while searching for food. After about four to five months they are weaned and are fully mature after about 18 months.

Predators and defences
Pottos have relatively few predators, because large mammalian carnivores cannot climb to the treetops where they live, and the birds of prey in this part of Africa are diurnal. One population of chimpanzees living in Mont Assirik, Senegal, was observed to eat pottos, taking them from their sleeping places during the day; however, this behaviour has not been observed in chimps elsewhere. Pottos living near villages face some predation from humans, who hunt them as bushmeat. They are sometimes harassed by African palm civets, although African Palm Civets are largely frugivorous.

If threatened, a potto will hide its face and neck-butt its opponent, making use of its unusual vertebrae. Pottos can also deliver a powerful bite. Their saliva contains compounds that cause the wound to become inflamed.

The highest recorded life span for a potto in captivity is 26 years.

Cognition and social behaviour
In a study of prosimian cognition conducted in 1964, pottos were seen to explore and manipulate unfamiliar objects, but only when those objects were baited with food. They were found to be more curious than lorises and lesser bushbabies, but less so than lemurs. Ursula Cowgill, a biologist at Yale University who looked after six captive pottos for several decades, noticed that they appeared to form altruistic relationships. The captive Pottos were seen to spend time with a sick companion and to save food for an absent one. However, there is no confirmation that this behaviour occurs in the wild.

Pottos in popular culture
The potto is not particularly familiar to people outside Africa, but some will know it from its appearance in Patrick O'Brian's Aubrey-Maturin novels. Virginia Woolf's nickname was 'Potto', and James Thurber sketched a potto for a series of animal cartoons. André Gide wrote an autobiographical story entitled Dindiki ou le pérodictique potto.

In the 1990s, there was also a short-lived children's science series, Professor Potto's Videolab. Here, Professor Potto, a friendly potto puppet, his researcher friend, Dr. Zeno, and their robot elephant, Big Maxx, teach kids science from the rain forests of Africa. They also have a cardboard box time machine to help illustrate the invention of things like batteries. Four VHS tapes were produced with the subjects of electricity, magnets, motors, and crystal radios. The series was also notable for providing a set of items with each tape that would allow the person watching to play along and do the same science as the characters on screen, such as building one's own working crystal radio, and more.