Christa Russell

Anthropology 2

Scientific Name:

Family - Loridae. In the Loridae family, there are four genera: Arctocebus which includes the species aureus and calabarensis, Loris which includes the species tardigradus, Nycticebus which includes the species coucang and pygmaeus, and Perodicticus which includes the species potto.

Common Names:

The common names for the species above respective in order (except for the aureus) are: "golden potto", "slender loris", "pygmy slow loris", and "potto".

Physical Descriptors:

The slender loris is about nine inches long, weighs about ten ounces, lacks a tail, has long arms and legs, quite large external ears, and very thin bodies. Their coats are gray or reddish but sometimes varies according to the subspecies. Their large eyes are surrounded by two black spots separated by a narrow white line that goes down its nose. The slow loris, who is larger and stockier than the slender loris, can grow to be twelve inches long, has a tail of two inches, and weighs about three pounds. Their coats are usually ash-gray and a darker dorsal line which divides the head into two branches that surround the eyes. The golden potto has a height of nine inches, a tail of half an inch, and weigh anywhere from seven to eighteen ounces. Their coat is an attractive light reddish color. Pottos are about twelve inches in height, weigh two pounds, and have a two inch tail. Their coats are reddish-brown to blackish with ears that have yellowish insides. Pottos usually live fifteen or more years. In captivity, Lorisoids usually have a life span of twelve to twenty-two years. All can stand and sit erect.

Lorisoids have the most vertebrae of all the primates. One characteristic of lorisoids is their unusual, powerfully grasping hand. All of their fingers and toes have nails, except their second finger is extremely short. The pottos are the only Lorisoids that have a normal size second finger with a claw on it. This claw is used to groom their head, neck, and ears. On Lorisoids, their only truly opposable toe is their first. Even though they have extremely short second fingers, the first and fourth fingers quite long. Like the Asian Lorises the potto's arms and legs are almost equal in length. The hand of the slow loris is specialized which creates a pincer-like grip. In the case of the potto and the golden potto, there is usually not even a trace of a second finger. There is, however, the remnant of the basal phalanx still embedded in the palm. Combining the reduction of the second finger with the increased length of the fourth finger and the highly abductable thumb, pottos and golden pottos have the longest possible span for grasping branches. The potto's hands have the most perfect grip of all living primates. All Lorisoids have a phenomenal grip that is comparable to that of a boa constrictor's. When they feed, they hang by their feet on a branch. Their grip is so strong they can pull themselves up without using their hands.

Lorisoids are able to see quite well in daylight as well as being nocturnal. This incredible night vision is due to the precision of their specially adapted retinas and other parts of their ocular apparatus. The pupils of their eyes are vertical slits that contract. All lorisoids, except pottos, have considerably large eyes compared to the size of their bodies. These large eyes are situated fairly far forward and close together on their comparatively short faces.

Lorisoids have thirty-six teeth with a dental formula of two incisors, one canine, three pre-molars, and three molars per quadrant. This dental structure is quite similar to that of the lemur-like creatures of fifty million years ago.

This group of primates have two tooth-combs. One is formed by the four lower incisors and the lower canines. The second is on the underside of the tongue and has sharpened and hardened points used to clean debris from between the teeth of the dental comb.

Lorisoids have an extremely low metabolic rate, such that they would die of cold if not for their fur coats, even in the tropics. They also have a very well-developed sense of smell. Their face is covered with hair and they have a moist, pointed snout.

The nape and back of a potto has a hump-like protriberances formed by a spinal process in which the vertebrae project through the shoulder blades and get covered by thick skin. This shield is covered by fur and tactile hairs two to four inches in length. These hairs detect any attack.

Behavior:

In event of an attack, the potto turns toward the attacker and buries its head between its hands and presents the neck bump as a shield. The potto dodges a charge by moving sideways without loosing its grip on the branch. Then it straitens its body and delivers fearful bites or violent blows with its shield, causing the predator to throw the potto to the ground. Once the potto is on the ground, it is very hard for the predator to get back to the prey.

The golden potto has no shield and is, therefore, incapable of such a defense. However, it can roll into a ball completely hiding its head and neck with only its short tail showing. This odd scene puzzles the predator, causing it to approach cautiously and sniff the tail-end of the golden potto. When seized by the rump, the golden potto bites the predator from under its arm. This makes the predator suddenly recoil and toss the golden potto several feet where it will role into a ball again.

All Lorisoids mark their territory with their urine. This usually happens when they wash their hands and feet in their urine. The slow loris is the only one in this genus to urine mark but not wash.

Lorisoids sleep in hollow trunks or forks of trees. They tuck their head and arms between their legs and curl up. Occasionally pottos sleep suspended from a branch.

Perhaps the next thing you might notice about these prosimians is the deliberate sluggishness in stalking prey, choosing holds on branches, and general movement. They move so carefully that they don't even disturb the leaves as they go by. Lorisoids move in a chameleon-like way, smooth and perfectly coordinated so much that they are not even noticed as they pass through the thick foliage. Their locomotion has developed to such a degree that they have lost their leaping skills. Only in a case of intense fear will they drop down to the ground in able to successfully escape their predator. Even the slightest sound will make them freeze mid-movement until the potential predator is gone. They are able to remain this way for hours in order to frustrate even the most patient prey. Only their heads and jaws can move with extreme rapidity.

Geography:

The slender loris lives in the forests of India, Sri Lanka, and Ceyon. The slow loris lives from Bangladesh to Vietnam, Malaysia, Sumatra, Java, and Borneo. Pottos live in the tropical forests of the West African coast from Guinea to the Congo and from Gabon to West Kenya. The golden potto live in South Nigeria, South Cameroon, Gabon, Congo, and West Zaire.

Habitat:

Lorisoids live in only the thickest vegetation. Most of the forest areas, where we find these creatures, are occupied by day-active monkeys and apes. Due to the fact that the monkeys are day-active, the Lorisoids do not compete ecologically with them.

The golden potto lives in wet, low forest rich in lianas.

Food:

Interestingly enough, the small species have seventy-five percent of their diet insects. Contrarily, the large species eat fruit and gum as seventy-five of their diet. When they do catch insects, they are usually slow-moving and are detected by their scent. The ability to eat prey that is just barely edible yet easy to locate by scent seems to be one of the few consequences of slow, imperceptible movement characteristic of pottos and lorises.

All Lorisoids eat a variety of leaves, insects, fruit, lizards, small mammals, infant birds, bird's eggs, flowers, and vegetables. Pottos, however, eat mostly fruits, some gums, small, prey such as birds, bats, and rodents eaten whole.

When Lorisoids want a drink, they find a leaf covered with dew or rain and stroke it with their finger in order to suck the moisture from their hand.

Population Structure:

Lorisoids usually live alone, occasionally roaming in pairs or small family groups.

Reproductive Strategy:

Pottos have 193 day gestation period. They usually have one offspring that weighs two ounces. The newborn is born with eyes open and their tiny body is covered with a thin layer of fine fur. From the day of birth, the infant clutches the hair on the mother's front and travels this way for the first few weeks. The offspring attain puberty in about a year.

The gestation period for the golden potto is 135 days. The mother gives birth to a white-spotted young that only weighs about an ounce. The mother is able to mate again a few days after giving birth. Weaning the baby takes place a few days before the next birth.

The slow loris has one two ounce baby.

Lorisoids don't make nests and are more developed at birth. They cling to their mother's belly while she sleeps and are left gripping a branch at night when she searches for food. She then comes back for it late in the night when she moves to forage elsewhere. After a little while, the offspring follows the mother first clinging to her back, then following her over long distances. During this time, the mother teaches the baby how to recognize different kinds of food. The baby is weaned between the fortieth and the sixtieth day after birth. The adolescent enters puberty sometime after the eighth month and leaves the mother when they are about a year old.

Currant Conditions:

Due to the fact that Lorisoids are quite small and nocturnal, they are not hunted systematically like such animals as monkeys. Few people have even seen these creatures in the wild. Man currently presents little real danger to their survival, apart from the areas that are threatened with destruction.

References:

Funk and Wagnall's New Encyclopedia. 1983.

Mammals: A Multimedia Enacyclopedia. National Geographic Society, Washington D. C. 1990.

Rosen, S. I., Introduction to the Primates Living and Fossil. London: Prentice-Hall. 1974.

Buettner-Janusch, John, Evolutionary and Genetic Biology of Primates. New York and London: Academic Press. Volume 2. 1964.

Schulz, Adolph H., The Life of Primates. New York: Universe Books. 1969.

All the World's Animals: Primates. New York and Toronto: Torstar Books. 1984.

Eimerl, Sarel and De Vore Irven. The Primates. Time Life Nature Library. New York: Time Inc. 1965.