The Living Primates
Genera: Allocebus (Hairy-eared dwarf lemur), Cheirogaleus (Fat-tailed dwarf
lemurs), Microcebus (Mouse lemurs), Phaner (Forked lemur)
Confined to Madagascar
With a body length of
61 mm (2.4 in) and a weight of a little over an ounce (30.6 grams) the pygmy
mouse lemur (Microcebus myoxinus) is the smallest living primate. Dwarf lemurs
have a tooth comb formed by long forward facing canines and incisors. These
teeth are used for scraping gum from trees. In forked lemurs the upper premolar
is shaped like an incisor.
Quadrupedal running, leaping and climbing. Sometimes they stand on their hind limbs to detect predators and survey their surroundings.
High-energy foods such
as insects, nectar, gums, and exudates. The larval secretions of insects are a
seasonally important food. Animal prey includes spiders, beetles, tree frogs,
and chameleons. Bird eggs are sometimes eaten.
The dwarf lemurs are
nocturnal and highly arboreal. During the cool-dry “winter” season when food is
scarce, some individuals hibernate for as long as six months. Males sometimes
fight over estrous females. Not much is known about their social behavior. It
is common to observe solitary animals.
Lemur (Lemurs),
Hapalemur (Bamboo Lemurs), Varecia (Ruffed lemur), Lepilemur (Sportive lemur)
Confined to Madagascar and the Comoros Islands
The true lemur
permanent dentition consists of 2 incisors, 1 canine 3 premolars, and 3 molars
on each side of the upper and lower jaws. Their elongated lower canines and
incisors are inclined forward and form tooth comb. The first lower premolar is
shaped like a canine. Sportive lemurs (Lepilemur) are exceptional in that they
lack upper incisors in their permanent dentition. Lemurs have nails on all
digits except their second toes, which terminate in specialized “toilet” claws
used for grooming. Glands that secrete oily substances that are used for
territorial marking are present in the scalp, wrist, arm, hands, feet, and
anogenital region.
Quadrupedal. Lemurs are agile arboreal aerialists
capable of leaping long distances. They sometimes suspend themselves upside
down by their feet while feeding on fruit and buds found at the tips of
branches.
The lemur diet consists mainly of fruit, leaves, flowers, sap, and other
vegetable material. Insects and arthropods, especially millipedes and centipedes,
are sometimes eaten.
Most species are arboreal and active periodically during the day and night. The ring-tailed lemur is active during the day and spends more time on the ground than the other lemurs. Some species live in one-male, one-female family groups. Ring-tailed lemurs live in multimale-multifemale groups led by a dominant female. Female ring-tailed lemurs are very aggressive and dominate the males in their group.
Genera: Avahi (Avahi lemur), Indri (Indri), Propithecus (Sifaka)
Confined
to Madagascar
Long hind limbs adapt indriids for vertical clinging and leaping. Their large salivary glands, stomachs, and colons reflect a leaf-eating speacializaiton.
Vertical clinging and leaping in the trees. Sometimes they suspend themselves by their feet while feeding in trees. On the ground they hop bipedally.
Leaves, buds, flowers, fruit, bark, and unripe seeds. Young leaves are preferred.
Indriids are areboreal and diurnal. The structure of their social groups varies. Sometimes they are found in family groups with one male qand one female or in small multimale-multifemale groups containing adults of each sex. Among sifakas, group size varies from 2-12 animals.
Genus: Daubentonia (Aye-aye)
Eastern coast of Madagascar
Aye-ayes have bushy tails and coarse, black, white-tipped, body hairs. Their continuously growing rodent-like incisors are unique among the primates. Adults have a single pair of incisor teeth and lack canines. Their molars are greatly reduced in size and a single premolar is present in the upper jaw. The skull is adapted to absorb the heavy gnawing forces generated by their incisors. Aye-ayes have extremely thin, wire-like middle fingers that they use to extract grubs from holes they gnaw in trees. They have claws on all digits except the great toe (hallux). Their brain-to-body-size ratio is high suggesting considerable intelligence.
Quadrupedal
Aye-ayes eat insects, grubs, and coconuts. In Madagascar they fill the niche of woodpeckers.
Aye-ayes are nocturnal and arboreal. Little is know about their social life. Solitary individuals are often observed and it is clear that they are not highly social. They use scent marking to define their territories and build elaborate sleeping nests.
Genera: Arctocebus (Angwatibo), Loris (Loris), Nycticebus (Slow Loris),
Perodicticus (Potto)
Lorises are found in India, Ceylon, and Southeast Asia. Pottos are found in Africa.
Lorises and pottos are small primates weighing less than 2 kilograms (4.4 pounds). They have large forward-directed eyes. They have greatly reduced tails, flexible spines, mobile ankle and wrist joints, and forelimbs that are about the same length as their hind limbs. Lorisids are manual predators and have strong grasping capabilities with vice-like hands and feet. This is facilitated by thumbs that diverge 180 degrees from the other digits. Lorisids have nails on all digits except the second digit of the foot (next to the innermost digit) which has a specialized “toilet” claw used for grooming. The second digit of the hand (index finger) is small, or vestigial. Adults have 2 incisors, 1 canine, 3 premolars, and 3 molars on either side of the upper and lower jaws.
Although they can move rapidly when capturing prey, their locomotion is usually extremely slow and deliberate quadrupedal climbing. They do not engage in leaping or springing. The lorisid adaptation involves slowly creeping along branches without vibrating them so that they can get within striking distance of insects and other small animals. After they are within range, they reach out with lightning speed and capture their prey by hand.
Fruit, gums, and animal prey.
Lorises and Pottos are arboreal and nocturnal. Adults spend much of their time in solitary foraging. Adults sometimes forage in pairs. Urine is put on the hands and used for scent marking. Male home ranges overlap with those of several females. In pottos copulation sometimes occurs while the male and female hang by their feet from a branch.
Genera: Euoticus (Needle-clawed bush babies), Galago (Bush babies), Galagoides
(Bush babies), Otolemur (Thick-tailed bush babies)
Confined to the forests of sub-Saharan Africa.
Bush babies have slender bodies, long bushy tails, and large delicate ears. They have elongated ankle bones and long hindlimbs adapted for acrobatic hopping and leaping. Their tails of some species are thick and bushy and act as a counter balance during long jumps. Urine is used for scent marking.
Quadrupedal climbing, running, jumping, and leaping. When jumping, their forelimbs land first.
Animal prey including caterpillars, beetles, butterflies and moths. Fruit and gum are an important dietary constituent for some species.
Bush babies are arboreal, nocturnal animals. Urine and scent gland secretions are used for territorial marking. Sleeping group size varies according to season and may be as large as 7-10 animals. Male territories are larger than those of females and typically overlap with those of several females. Galagos are called “bush babies” because their calls sound like a crying baby. Each species has a distinctive call that is recognized by conspecifics.
Genus: Tarsius (Tarsiers)
Southeast Asia: Borneo, Sumatra, Sulawesi, and the Philippines.
Tarsiers are small, kitten-sized primates. They have elongated tarsal (heel) bones and long legs that adapt them for vertical clinging and leaping. Tarsiers have nails on all digits except their second and third toes, which have claws. Their tail, which is stiff and hairless except for a tassel at the tip, is used for balance and to keep them from slipping down the vertical supports they cling to. Tarsiers have some advanced features similar to those seen in monkeys, apes, and humans. Instead of being open in the back as in lemurs, the tarsier’s eye socket consists of a bony cup and, in this respect, is like that of the higher primates. Tarsiers lack the split upper lip and wet nose of prosimians. Instead, they have a continuous upper lip and hairy nose that more closely resembles that of a monkey than a prosimian. Tarsiers can turn their head 180 degrees like an owl.
Tarsier locomotion mostly consists of vertical clinging and leaping and climbing. They occasionally walk or hop on horizontal branches. They can jump as far as 5.6 meters (18 feet) in a single bound.
Tarsiers are the only primates whose diet consists entirely of animal material. They eat insects, lizards, and spiders.
Tarsiers are nocturnal arboreal predators of small animals. They spend much of their time low in the forest in thickets that provide many vertical supports. Tarsiers live in one-male one-female groups as well as larger social units containing several members of both sexes. Males, females and subadults sometimes sleep together in dense vegetation or hollows of trees. They have loud sex-specific, bird-like calls.
The anthropoid primates
differ from the prosimians in several respects. They place less emphasis on the
sense of smell than prosimians and, as a consequence, their brains have small
olfactory lobes. Anthropoids lack the wet nose (rhinarium) and split in the
upper lip (philtrum) seen in lemurs. Instead they have unsplit nostrils and a
free upper lip (a condition also found in tarsiers). This greater lip mobility
opens the possibility for elaboration of social communication through facial
expressions.
The name Platyrrhini
means “flat nose” and refers to the broad noses and round, side-facing nostrils
of the New World monkeys. Catarrhini (Old World monkeys, apes and humans) have
narrow noses with nostrils that face downward. The Platyrrhini have three
premolars and differ in this respect from the Catarrhini, which retain only
two. All New World monkeys are highly arboreal. Although most are active during
the day, the infraorder includes a nocturnal group, the night monkeys (Aotus).
Genera: Callithrix (Marmosets), Leontopithecus (Tamarin), Saguinus (Tamarin), Cebuella (Pygmy Marmoset)
Genus: Callimico (Goeldi’s monkey)
Forests of Central and
South America.
The Callitrichids are small primates that weigh less than
1kg (2.2 pounds). They have small brains relative to their body size and sharp squirrel-like claws on all digits except the
great toe. They lack the prehensile tails found among some of the larger New
World monkeys. Selective pressures for small size have resulted in tooth
reduction among the marmosets. With the exception of Callimico, all species
lack third molars. In Callimico, the third molars are greatly reduced.
Marmosets have simple upper molars with three main cusps that contrast with the
more complex four-cusp molars of other Old and New World monkeys.
The pygmy (Cebuella) and common (Callithrix) marmosets have lower
canines and incisor adapted for gouging the bark of trees. They use these teeth
to gnaw round or slit-like holes in the bark of trees. The sap that exudes into
these gnawed areas provides marmosets with a nutritious food source. In some
species, the cecum is specialized for digesting these exudates. Tamarins
(Leontopithecus, and Saguinus) lack this dental specialization for gum eating.
Marmosets of
the genus Callimico (Goeldi’s
monkey) are exceptional in several respects. Although they are like marmosets
in their small size and the presence of claws, they retain three molars and
have single births (the other marmosets normally bear twins).
Fruit, animal prey,
exudates, gums, seeds, nectar, and buds. Callithrix and Cebuella frequently eat
gum from trees. The lion tamarins (Leontopithecus) are a little larger than the
other callitrichids and do not eat exudates. They use their narrow fingers to
search out insects in vegetation, from under bark, and in tree holes.
Quadrupedal branch running. Vertical clinging and leaping between tree trunks is fairly common in some species.
Marmosets and tamarins are diurnal, arboreal primates. Black lion marmosets sometimes come to the ground to forage for insects in the leaf litter. Marmoset social structure varies from one male‑one female to multimale‑multifemale groups. Marmosets live in larger groups than tamarins. Territories are defended through vocalization. Scent marking of branches is used to identify regular trails. Parental care is shared by both sexes. Usually only the dominant female breeds and the young are raised communally by the entire group. The scent of a dominant female suppresses the estrous of subordinate females.
Genera: Cebus (Capuchin monkeys), Saimiri (Squirrel monkey)
Genus: Alouatta (Howler monkeys)
Genera: Brachyteles (Wooly spider monkey), Lagothrix (Woolly monkeys)
Genera: Aotus (Owl monkeys), Callicebus (Titi monkeys)
Genera: Cacajao (Uakaris), Chiropotes (Bearded sakis), Pithecia (Sakis)
Forests of Central
and South America
The cebids are larger than the marmosets with weights of
over 1 kg (2.2 pounds). The largest members of this group weigh about 10 kg (22
pounds). They differ from the marmosets (with the exception Callimico) in
having three molars instead of two.
The cebids are a diverse group and it is difficult to
generalize about them as a whole. Many of the larger species (howler monkeys, spider monkeys, and
wooly monkeys) have elongated limbs and long tails with fingerprint-like friction
ridges on its underside and well-developed grasping capabilities. A distinctive
feature of spider monkeys is their reduced thumb, which is either absent
or represented by a small stump. The uakaris and sakis have specialized incisors and robust canines
adapted for seed processing. Titi monkeys (Callicebus) have short faces and
long, non-prehensile tails.
Although all of the
cebids eat fruit, the spider monkeys (Ateles) are the most highly frugivorous.
Leaves make up a substantial part of the diets of howling (Alouatta) and wooly
spider (Brachyteles) monkeys. Although squirrel monkeys (Saimiri) mainly
eat animal prey including insects, spiders, and frogs, fruit such as figs are a
seasonally important food source for some species. The uakaris and sakis are seed eating specialists.
Quadrupedal walking,
running, and leaping. Those cebids who have prehensile tails use them to
suspend themselves under branches while feeding. Spider monkeys use their long
arms to brachiate under branches. Sakis are excellent leapers. Howling monkeys
are more quadrupedal than spider monkeys and some species frequently travel on
the ground.
With the exception of a few monogamous forms, most cebids live in multimale-multifemale groups. The size and organization of these social groups varies. Squirrel monkeys (Saimiri) live in large groups that sometimes contain twenty or more animals. Squirrel monkey males fight over access to females and females form coalitions to dominate males. Capuchin monkeys (Cebus) live in smaller troops with one dominant male. Lower ranking males sometimes form their own subgroup.
Howling monkeys usually live in one
male-multifemale or multimale-multifemale groups. Spider monkeys (Ateles) live
in fluid communities whose size depends in part on local resource availability.
Titi monkeys (Callicebus), night monkeys (Aotus), and sakis (Pithecia) live in
one male-one female family groups and form monogamous pairs.
The name Catarrhini
means “hook-nosed” and refers to narrow nose and downward facing nostrils that
differentiate the Catarrhini from the Platyrrhini who have wide, flat
noses with side-facing nostrils. The number of teeth also differs between the
two groups. All catarrhines have two premolars, instead of three as in the
platyrrhines. Catarrhines have flattened
nails on all of their digits and differ
in this respect from the lemurs and some New Wold monkeys (i.e.
marmosets and tamarins). In contrast to the
Platyrrhini, which are all highly arboreal, some of the Catarrhini (baboons and humans) are adapted for life on the
ground. Most catarrhines have specialized areas of skin on their buttocks
(ischial callosities) that serve as pads when they sit on the branches of tree. The exceptions are humans
and the great apes
The Old World monkeys are divided into two subfamilies with different dietary adaptations. The leaf monkeys (Colobinae) eat large quantities of mature leaves and buds. The cheek pouch monkeys (Cercopithecinae), in contrast, are more omnivorous and many of them have a fruit based diet. The members of both suborders have distinctive molars with four main cusps connected by transverse ridges (bilophodont molars).
Genera: Cercopithecus (Guenons and Vervet), Allenopithecus (Swamp monkey), Miopithecus (Talapoin), Cercocebus (Mangabeys), Erythrocebus (Patas monkey), Macaca (Macaques), Mandrillus (Mandrill and Drill Baboons), Papio (Baboons), Theropithecus (Gelada baboon)
Mostly in Africa but macaques are found in Asia as far north as Japan as well as in North Africa.
Cercopithecines have simple stomachs
and cheek pouches that they use for storing food. Most species have long tails,
but tails are greatly reduced in some forms such as Japanese (Macaca fuscata)
and Celebes (Macaca nigra) macaques. A sexual swelling occurs in the perineum of females at estrus
among the baboons, macaques, mangabeys, talapoins, and swamp monkeys. Vervets
and guenons lack estrous swellings.
Quadrupedal. Ground dwelling species walk with the weight of the front of their body supported by their fingers and palms of their hands raised off of the ground (digitigrade).
Cercopithecines are omnivorous. Most species show a preference for fruit. Terrestrial forms eat roots and tubers they dig out of the ground with their hands. Some baboons hunt small mammals and eat a considerable amount of meat.
The Cercopithecinae are diurnal primates with arboreal, semiterrestrial, and terrestrial adaptations. Most live in multimale-multifemale groups with well-delineated dominance hierarchies. Some species, such as the gelada baboon (Theropithecus), have one male-multifemale groups as the basic social units. Guenons are organized around a core group of females that remain together throughout their lives. One male is usually associated with a group of females.
Genera: Colobus (Colobus monkeys), Nasalis (Probosis monkey), Presbytis (Leaf
monkeys), Procolobus (Red colobus monkeys), Pygathrix (Snub-nosed monkeys),
Semnopithecus (Hanuman langur), Trachypithecus (Brow-ridged langurs)
Colobus Monkeys (Africa), Langurs (Asia)
Colobine adaptations for a leaf-based diet include the absence of cheek pouches, large sacculated stomachs that are divided into three (Colobus) or four (Procolobus) chambers, and enlarged salivary glands. Colobine molar teeth have high pointed cusps with sharp shearing crests adapted for shredding leafy material. The thumbs are absent or greatly reduced in the colobines.
Quadrupedal, with frequent leaping. The forelimbs are used to break falls in a form of locomotion know as semibrachiation that involves both leaping and arm-swinging.
Mature leaves and other plant parts with a low energy value are important food sources. Fruit, buds and flowers are also eaten.
Most species of leaf-eating monkeys live in one male multifemale groups. Peripheral males sometimes live alone or in multimale groups. Among Hanuman langurs, when new male takes over a group, he frequently kills the unweaned infants of the previous males. Males who kill infants will have more offspring than males who don’t because nursing suppresses ovulation in females. Among many colobines, several females share infant care.
Genus: Hylobates (Gibbons)
Forests of the Southeast Asia mainland and adjacent islands
Gibbons have
extremely long arms, hook-like fingers, and well-developed thumbs that fold out
of the way against the palm of their hands. These specializations are
adaptations for swinging below branches (brachiation). Gibbons lack an external
tail and have ischial callosities similar to those of Old World monkeys. They
do not have estrous swellings. Males an females are of similar size and both
sexes have long canines.
Brachiation (arm swinging) plus climbing. Gibbons walk bipedally on horizontal supports in the trees, and when forced to the ground, gibbons walk bipedally. In such circumstances, they use their long arms like the balance pole of a tightrope walker.
Although the gibbon diet is composed mostly of ripe fruit, they also eat some buds and leaves. They occasionally eat birds and other animals. Siamangs (Hylobates syndactylus) are bigger than the other gibbons and also eat more leaves. The siamang’s large body size may be an adaptive response to this low energy diet.
Gibbons live in monogamous family groups. When offspring mature, they are often expelled from the group. Gibbons are highly territorial. Adults of both sexes defend the families foraging area using loud whooping vocalizations and acrobatic locomotor displays.
Genera: Gorilla (Gorilla), Pan (Chimpanzees), Pongo (Orangutans)
Gorillas and Chimpanzees (equatorial
Africa), Orangutans (Borneo and Sumatra).
The
great apes are large bodied primates with large brains, long forearms, and many
morphological similarities to humans. Chimpanzees are the only pongids with a
pronounced estrous swelling. The thumbs and great toes of orangutans are
greatly reduced.
In the trees, all of the great apes occasionally engage in subdued forms of brachiation, especially when they are young. On the ground, gorillas and chimpanzees use a specialized form of four-limbed locomotion known as knuckle-walking in which part of their weight is borne by the middle bone of their fingers. When orangutans walk quadrupedally on the ground, they do not knuckle walk but instead use their flexed fists for support.
All eat fruit and leaves. Orangutans eat fruit, except during the dry season when they are forced to feed on bark and other lower energy foods. Gorillas specialize in eating foliage and have never been seen to eat mammals in the wild. Chimpanzees frequently kill and eat animals, especially other primates.
Among orangutans, females associate with their infants and males are solitary. Gorillas live in groups containing one or two adult males along with several females and their offspring. Young male gorillas leave their natal group at adolescence. Chimpanzees live in multimale-multifemale communities with a fluid social organization.
Cosmopolitan
Large brained, long legged primates adapted for bipedal locomotion. Lacks an opposable great toe. There is substantial geographical variation in skin color. Hair is vestigial over most of the body. Many males have heavy facial hair that is lacking in females.
Habitually bipedal, standing, striding
and running
Omnivorous. Most food is produced through agriculture. Diet is supplemented by fishing and hunting.
“KNOW THYSELF”
South and Southeast Asia; offshore islands
Treeshrews are small squirrel-like animals with long snouts, and claws on all digits. Their eye sockets directed to sides and not enclosed completely in bone. Treeshrews have 2 incisors, 1 canine, 3 premolars, and 3 molars on either side of the upper jaw, and 3 incisors, 1 canine, 3 premolars, and 3 molars on either side of the lower jaw. Their upper incisors tend to be canine-like. The lower incisors protrude forward and in some respects resemble the tooth-comb of lemurs. In the past, treeshrews have been considered primates because they show structural similarities to early primate such as a large brain for their body size and thumbs that tend to diverge from its fingers. Most researchers now view such similarities as either independently evolved adaptations to similar environments or simply retentions primitive mammalian characteristics.
Treeshrews are quadrupedal. They
scurry much like a squirrel on the ground as well as in the trees.
Treeshrews are omnivorous. Forage in bushes and leaf litter of the forest floor for fruit and insects.
Some animals are solitary, others live in pairs and defend their territory against other treeshrews.
Order Scandentia
Family Tupaiidae
(tree shrews)
Like elephant shrews, tree shrews have often been considered a divergent family of Insectivora. Some investigators have suggested that they might also be related to Primates. Here, we follow Anderson and Jones (1984) and place them in their own Order, Scandentia. The order contains one family (Tupaiidae) and around 16 living species.
Tree shrews are remarkably squirrel-like in external shape and size, and in fact I have seen them in pet stores being sold as Asian squirrels. Even their tail is squirrel-like, long and heavily furred. They lack the long vibrissae of squirrels, however, and their feet are also rather different.
The molars are broad and have a W-shaped cusp pattern.
Tree shrews are omnivorous. Their eyes are large and their hearing is excellent. They may be found in trees or on the ground. Socially, some species are solitary, others are found in pairs or even small groups.