When most people think of primates, they often refer to chimpanzees, gorillas, baboons, and probably capuchin monkeys too. Very few people realise that the Order Primates, or the taxonomic classification of mammals, includes all lemurs, monkeys, apes and even humans. These primates spread across 4 different regions: Madagascar, Africa, Asia and the Neotropical region, which consists of Mexico Central and South America.

Considering that the entire Neotropical region contains sixteen genera and ninety-eight species of primates, The Neotropics are no doubt a primate wonderland. Besides, this is the only place where one can find monkeys with prehensile tails. For example in South America rainforests, generally two families of monkeys occur, namely the marmosets and tamarins and the larger capuchin-like or cebid monkeys.

Marmosets and tamarins are small, weighing about 300g each. Many of these species has manes and limbs, which can be of different colours from the rest of their bodies. Unlike most monkeys, they are monogamous and feed on fruits, flowers and forage for small animals. However, some species have a predeliction for plant saps and gums. Only a single marmoset species can inhabit any particular area, but sometimes several tamarin species fit into divergent ecological niches of the same habitat. The center of diversity is upper Amazonia, and no species occurs in northern South America.

Three species of marmosets occur in the region. One of which is the brownish Pigmy Marmoset. With a weight of 190g, it is the smallest New World monkey. It is restricted to the upper Amazon, in Brazil, Peru, southern Colombia and northern Bolivia. Also a habitat specialist, its population is at the highest in the riverside and seasonally flooded forest. They occupy up to 40-50 groups/ sq. km in such areas, in contrast to areas away from rivers and in secondary forest where they occur in lower densities. Like the seven larger marmoset species, The Pygmy marmoset is a specialized gum eater. In fact, exudates are a larger part of the diet of the Pygmy marmoset than other marmosets. These marmosets spend about 67 percent of its feeding time looking for gums and saps in trees. They make many small, 8-15 cm holes in the bark of a tree and return the next day to feed on the sap or gum that is collected. However, only certain species of trees are used. This varies with the places. In the dry seasons, tamarins may also come by to ‘steal’ sap. Marmosets also feed on insects and occasionally, fruits. Like other marmosets and tamarins, Pygmy Marmosets live in extended family groups of between 4 and 15 members. They travel silently and are shy and difficult to spot. The best way to find them is to wait near freshly made holes on the feeding trees in early morning or late afternoon. On the south of Amazon lives a nearly white species with pink face, namely the Bare-ear or Silvery Marmoset. The remaining species is the Tassel-ear Marmoset, which occurs between the Madeira and the Tapajos rivers.

As for the tamarins, the eight species of the region have evolved numerous subspecies with quite divergent colours. Some species are mainly black, like the Red-handed Tamarin and the Emperor Tamarin. Nevertheless, their bright coloured features can tell them apart. For example, the latter has a bright moustache and beard, in contrast to the other, which has red hands and feet.

Much bigger than the previous family are the capuchin-like or cebid monkeys, each weighing between one and several kilograms. They are also mainly black, like the Red-handed Tamarin and the Emperor Tamarin. Nevertheless, their bright coloured features can tell them apart. For example, the latter has a bright moustache and beard, in contrast much more diverse in their appearance and their ecological adaptations. They feed on everything from fruits and leaves, to insects and other mammals. One of the 30 species occurs only in a small and isolated mountain range (e.g. the Yellow-tailed woolly monkey), while others like the Night Monkey have spread throughout tropical South America. Generally, cebid monkeys are found in tropical and subtropical evergreen forest. Unlike many of the Old World primates, none of the cebids shows obvious specialization for life on the ground. They live almost exclusively in trees, although some will descend to the ground to play or look for food. Another of such species is the Titi Monkey (genus Callicebus).

There are 3 species of Callicebus monkeys, namely the Dusky Titi (Callicebus moloch), the Yellow-handed Titi (Callicebus torquatus) and the Masked Titi (Callicebus personatus). While the Dusky Titi population is spread in South America, from Colombia to Bolivia and Paraguay, and south of the Amazon in Brazil, Yellow-handed Titi can be found in east of the Andes of western Amazon Basin and also in lowlands of Colombia, Venezuela, Peru and Brazil. Masked Titi can be found in East Brazil, stretching from Bahía to Sao Paulo. Feed on, often, unripe fruits, insects and leaves, Callicebus monkeys prefer understories up to 10m. All 3 species are small and light-weighed, each weighing about 1kg (2.2lb). Nevertheless, one can tell them apart from their coat colour and pattern. For example, all 3 species have tails of different pattern and colours. The Dusky Titi has pale cream of dull yellow patch at the tip of the tail. This is absent in the Yellow-handed Titi and the Masked Titi, where the tail is always dark brown to black and reddish-brown respectively. Another way to distinguish them is by looking at the colour of their hands. The Dusky Titi hands vary from gray to brown to red in colour, while the Masked Titi has black hands. The Yellow-handed titi, as the name suggests, has yellow hands. All titi monkeys live in groups of 2-5 individuals. They occupy small territories and make loud morning calls to regulate intergroup spacing. The calls that echo throughout the forest of distances of 600-700m is a striking feature of the titi monkeys’ social behaviour. However, these species do not depend entirely on vocalizations to do this. Species like the Dusky titi moves to their territorial boundaries, which they have rigidly maintained over the years, and confront each other vigorously. The Yellow-handed Titi, in contrast, regulates intergroup spacing by calling from within the territorial boundary. These boundaries shift over the years. Another amazing social behaviour of the titi monkeys is that the males are most indulgent and spend much time with the offspring. In fact, the father is the primary caretaker of the young. Observations made shows that the young spends much more time with the father than with the mother or the siblings. Most importantly, the father is responsible most of the time for carrying the young through the trees. However, he will occasionally give the infant up to the mother for nursing, or the sibling to carry it. Like most primates, adult titi monkeys grooms each other in the day. In addition, the Yellow-handed titi has an extensive period of grooming just before the sun sets. The entire group gathers and members take turns grooming each other, although most of the time is devoted to grooming the youngest offspring. As the sun sets, the entire group crowd close together to sleep, with their tails entwined.

Like the species, mentioned above the gorilla is also an anthropoid ape. In fact, it is the largest of the group that consists of human beings, apes and monkeys. There is a single species of gorilla (Gorilla gorilla) with three distinct subspecies; they are the western lowland gorilla(Gorilla gorilla gorilla), the eastern lowland gorilla (Gorilla gorilla graueri) and the mountain gorilla (Gorilla gorilla berengei). The one with the widest distribution is the western lowland gorilla, which is found in a small part of eastern Nigeria, but mainly in the area stretching from Cameroun to Congo (Brazzaville). The eastern lowland gorilla lives in a small area of eastern Zaire to the west of Lake Tanganyika and the mountain gorilla is restricted to a tiny area of the Virunga Volcanoes which border on Zaire, Rwanda and Uganda. There are various ways of distinguishing the 3 species. One way is by comparing the coat or hair. The western lowland gorilla has relatively short hair with brownish tinge, especially on the top of the head. The adult male’s silvery-white saddle extends onto the rump and thigh while the one of the eastern lowland gorilla is restricted to the back. Mountain gorillas have longer black hair especially on the arms. Other species’ are shorter. Just like the western lowland gorilla, the silver saddle also extends onto the rump and thighs. Gorillas live in groups ranging in size from 2-37 individuals. The western populations have smaller group sizes, with an average of 5 members, while eastern groups, nine. A typical family group of gorillas consists of one male, several adult females and five or six young ones. The male, having a silver-grey mark on his back, stands out from the rest, who are all black over. That is why the male is called a ‘silverback’. Newly mature male gorillas are forced to leave the group and remain solitary until they can find females to form a group of their own. The diet of the eastern and western gorillas differs much. For example, eastern lowland gorillas and mountain gorillas feed on herbs, shrubs and vines while western lowland gorillas feed on leaves, pith and stems, as well as fruits. They are quadrupeds and walk on the flat of the feet and knuckles of the hands.

The other suborder to the Primates is the Prosimians or ‘lower primates’. They show less advanced evolutionary trends and are less man-like, as compared to the anthropoids, or ‘higher primates’. Prosimians tend to have longer snouts and stronger sense of smell. An example would be the Tarsiers. Consisting of 3 species, tarsiers are found on islands of Southeast Asia, and the Philippines. The species living today includes the Sunda or western tarsier (Tarsius bancanus), the Philippine tarsier (Tarsius syrichta) and the Celebes tarsier (Tarsius spectrum). The term ‘tarsier’ refers to the special situation in the bone structure of the hind legs. Their tarsal bones are elongated which enables them to leap long distances. Using vertical clinging and leaping with their very long hind legs to move from tree to tree, they search for insects, other invertebrates and small vertebrates, such as lizard, to feed on. They are all very similar in appearance. All 3 species has excellent adaptations to the hunting of small preys at night. All have large, independently movable ears, enormous efficient eyes, and a head that can rotate through 180 degrees. One unusual point about its features is that they are unable to move their eyes within the socket. Besides, another special trait of the tarsiers is the absence of nose leather. This helps to distinguish them from all prosimians.