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Bizarre Animals - The South American Uakari Monkey

By Edited Dec 13, 2013 1 3

The Bald-Headed Uarkari

The uakari monkey is another amazing animal native to South America. This continent has some incredible animals and birds.

The capybara is one, the largest rodent on earth today while the hoatzin bird is known as the 'stink bird'. Then there is the giant anteater and the tamandou, both of which are quite bizarre to westerners used to cats, dogs and parrots.

The uakari has its own claim to fame with its striking bald head and bright red face. It is also called the bald uakari or bald-headed uakari. Its taxonomic name is Cacajao calvus. It is a small New World monkey with four subspecies. All are regarded as vulnerable by the IUCN.

Distribution Map(85422)

The uakari monkey
lives only in the western Amazon River basin of Brazil and Peru, and only in white water flooded areas. They are therefore highly susceptible to human impact.

Its preferred habitat is rainforest areas that are permanently or seasonally flooded. They are also found near water sources such as small rivers and lakes. These are arboreal animals, spending most of their time in the trees. Major flooding occurs during the rainy season and the uakari stays in the canopy. They are the only species of monkey in the area that can stay in the canopy for an extended period of time.

The uakari is covered with long, shaggy hair. This can vary in colour from white to reddish brown to orange, depending on the species. Unusual for a monkey is the very short tail of about 15 cm.


The scarlet red face is the result of both a lack of skin pigmentation and abundant capillaries just under the skin. Males have a fatty bulge on the forehead. This bulge has a centre indentation. Uakaris weigh about 4 kg (9 pound). They are not attractive. Oversized, splayed canines, stumpy tail and that fur with a bright red face – only another uakari could love it.

Although there is virtually no tail, these monkeys are able to move quickly and competently through the jungle. They are social animals and forage during daylight hours, mostly in the trees but during drier periods when food is scarce, they will come down to forage on the forest floor for fallen seeds or roots.


These monkeys live in groups of about forty but may be up to a hundred (rarely). The group splits up into smaller numbers during the day to search for food. At night, they sleep high in the canopy of the rain forest.

Up to 4.8 kilometres a day may be covered while searching for food. Home ranges cover 500 to 600 hectares. Some of the defence mechanisms which the uakaris employ to deter intruders include specific vocalisations, wagging the tail and bristling the coat to make themselves look bigger. Uakaris often travel with other monkeys such as woolly or squirrel monkeys or capuchins but the reasons for this are not clear. It may be that there is safety in numbers.

On approaching maturity, males are forced out of family groups and form bachelor groups. The social system is not well understood and it is not clear how many of the females mate with a dominant male.

The main component of their diet is fruit, together with some leaves and insects. Unripe fruits are spread more evenly through the forest so the small groups fan out. The powerful lower jaw lets them break open hard, unripe fruits that other primates would not be able to access. Over-sized canines break open the tough outer shell and the incisors are then used like tweezers to extract the kernel or seeds. They have no trouble breaking open a Brazil nut. The diet consists of 67% seeds, 6% flowers, 5% animal protein of some sort and buds. Although they eat insects, they don't go out of their way to catch or find them.

The bright red face is a sign that the monkey is healthy. Capillaries lie very near the surface and sick animals will have a pale face. These are avoided as potential mates.

Breeding takes place between October and May. Females release an attractive scent when she is ready to mate. A single offspring is born every two years. Females are not sexually mature until three years old and males until they are six so populations are slow to show much increase. The gestation period is not known but the lifespan is about twenty years.

The uakari is hunted for food by local tribesfolk. Populations of the monkey are located close to the Amazon River with an increased risk of hunting from canoes. The monkeys are a food source and are also used as bait.

The timber industry is also cutting great swathes through the tropical forest of the Amazon making habitat loss a major obstacle to the continues existence of this unusual monkey. Logging of hardwood disrupts the continuity of the forest canopy directly affecting the uakaris' arboreal lifestyle and seed food consumption.

The Yavari river basin of north-east Peru has a low human population which has resulted in an abundance of large mammals and an incredible biodiversity of species. Thirteen species of monkey are found here.

The status of the uakari in 2008 was gauged by the IUCN as 'near threatened'. It has since been upgraded to 'vulnerable'. The change occurred because the species declined at least 30% over 30 years (3 generations). Habitat loss is of great concern. An average of 15.4 million hectares of tropical forests were destroyed EACH YEAR between 1980 and 1990 with the Amazon Basin having the highest rate of forest destruction

There are a number of conservation projects underway with the aim of protecting portions of the habitat of these monkeys. A Pilot Program set up in 1999 by the World Bank aimed to put 350 million dollars into conservation programs for the Amazon.

In 2003, the Amazon-Andes Conservation Program was set up to protect seven landscapes in the Amazon (approximately 3% of the Amazon Basin). The Wildlife Conservation Society is hoping to extend these areas soon. The Brazilian army is also being employed to patrol the Amazon for evidence of illegal logging, deforestation and mining.

Although as ugly as sin, it would be a shame to see the uakari monkey disappear.



Feb 16, 2012 4:27am
Animals such as these -- it's amazing how they have managed to survive in such a restricted range. Compared to the size of the Amazon, this little pocket must be equivalent to any of us having a unique species living under one -- and only one -- of our living room chairs!

I have seen something on these guys on Discovery once, and there is a theory that the capillaries close to the skin are a mating adaptation -- the chicks dug the red-faced monkeys, and that trait got passed along. , getting deeper red. Your point about pale faces equaling sick monkeys and mating avoidance supports that theory nicely. As always, excellent work.
Feb 16, 2012 4:33am
Thanks Bill. In the case of the elephant, the bull elephants with the really long tusks are getting continually poached and consequently conservationists are now seeing elephants with shorter and shorter tusks as the 'long-tusked' gene disappears forever.
Feb 16, 2012 4:45am
Ain't humanity grand? That's sad to hear.
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