Strange Animals of the Amazonian Rainforest

The Amazonian rainforest has the greatest biodiversity of any tropical rainforest. It is home to one in ten of known species; one in five of all bird species and one in five of all fish species. It houses at least 427 mammals, 1,294 birds and 428 amphibians. While many of the mammals which live in the rainforest are known at least by name to many people, there are others which are secretive and rarely seen. Some are quite bizarre and information on some of these species is scanty.

 The following are some of the lesser known animals of the Amazon.

Pygmy Marmoset

Other names for this little creature are dwarf or pocket monkey, or little lion. It is native to Brazil, Ecuador, Peru, Bolivia and Colombia and is known as the world's smallest monkey. It weighs a mere 4 to 7 ounces when fully grown. Its tail averages 8 inches and is longer than its body (5 inches). Family groups live together. It is omnivorous with its main food source being tree sap. The teeth are adapted for digging into the bark of trees. It also eats fruit, insects, small reptiles and leaves. The lifespan in the wild is 11 to 12 years.


Pygmy MarmosetCredit: Wikimedia

Three-toed Sloth

These tree-dwelling mammals move at around 0.15 miles an hour. They actually swim faster than they walk. They live in the lower layers of the rainforest, clinging to trees with extremely long claws. Algae often grows on the long strands of the fur, giving it a green hue and providing effective camouflage. They weigh between seven and ten pounds. They spend a lot of time hanging upside down from branches, so much time in fact that the fur grows out and down from the belly allowing tropical downpours to drain off more easily.

SlothCredit: Wikimedia

Giant Anteater

The giant anteater grows to a length of seven feet, nearly half of which is tail. The tongue is only half an inch wide but two feet long. It is covered in a sticky saliva. The tongue is flicked in and out of ant nests, ants stick to the tongue and are transported to the mouth. There are no teeth but the ants are ground against the roof of the mouth. When threatened, the animal rears up and strikes at its predator rapidly with its sharp claws. It is quite able to fend off pumas and cougars. It is classed as vulnerable.

Giant AnteaterCredit: Wikimedia

Black Caiman

This is the largest predator in the Amazon basin with most adults growing to between nine and fourteen feet in length. It is dissimilar in structure to other caimans with a larger skull and eyes. It is also more robust. The scaly skin is dark with pale bands across the flanks and grey or brown banding on the lower jaw.

Black CaimanCredit: leofleck [CC-BY-SA-2.5 (, GFDL ( or CC-BY-SA-3.0 (], from Wikimedia Commons

 As an adult, it is an opportunistic hunter taking turtles, mammals and birds. Many large mammals such as horses, cattle and tapirs are taken when they come to the rivers to drink. This species may hunt on the ground at night as it has acute hearing and sight.

 They often drown their prey before swallowing it whole as their teeth are designed to grab, not chew. Large prey may be stored until it rots enough for the caiman to takes chunks out of the flesh. It is listed as 'conservation dependent' as it has been hunted to near extinction for its skin.


The capybara is the world's largest rodent. It is semi-aquatic and found through most of South America. It has a barrel-shaped body with a short head. It measures up to 53 inches in length, two feet tall and weighs between 77 and 146 pound. The thin coarse hair gives good protection from the undergrowth without allowing the animal to become too hot.

CapybaraCredit: Wikimedia

The coat is reddish-brown with creamy underparts. In the heat of the day, the capybara wallows in mud or water. Unusually for rodents, there are sweat glands in the skin surface. The feet are slightly webbed.

 The ears, eyes and nostrils are all situated on top of the head. Food is ground back and forth rather than from side to side. The front teeth grow continually as do the cheek teeth. This gentle creature is easily tamed and some are kept as pets. It is not considered threatened although it is hunted for its meat and hide.

Mammals of South America
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Stunning photographs and engaging
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Amazonian rainforest.

Uakari Monkey

The uakari monkey has a bald  head and bright red face. It  is found in white water flooded areas of the western Amazon River Basin. They are arboreal, capable of staying in the canopy for extended periods. It has a long, shaggy coat which may vary from white to reddish brown or orange. The tail is very short, about 15 cm.

Uakari MonkeyCredit: Wikimedia

 Males have a fatty bulge on the forehead with an indentation down the centre of the bulge. The canine teeth are oversized and splayed. They forage in social groups through the day, mostly in the trees but feed on the forest floor when food becomes scarce. The status of the uakari monkey is 'near threatened'. Local tribes hunt the animal for meat and for bait. Near the Amazon River it is hunted from canoes.


 This slow-moving rodent has a superficial similarity to the paca. Although not as large as the capybara, it has a chunky body and weighs up to 33 pound. The body length is 31 inches and has a thick furry tail. They are usually seen in small groups of four or five.

PacaranaCredit: Wikimedia


The paca is considered a luxury food source in some areas. It is a ground-dwelling, herbivorous rodent, 20 to 30 inches in length and weighing 13 to 31 pounds. They have square heads, spots and stripes on the sides and an almost invisible tail. The robust, heavy body is cone-shaped and the legs are long and fine. They swim really well and can stay submerged for up to 15 minutes.

PacaCredit: Wikimedia

They normally forage in the morning and afternoon but will become nocturnal if there are lots of predators around. Burrows up to three metres deep are constructed with two entrances camouflaged with leaves. They have resonating chambers in the cheeks and make a surprisingly loud growling noise. They are important in seed dispersal and often centre their territories on a patch of fruit trees.


The South American tapir is recognised as endangered although it has a lower risk of extinction than the other three species. It may be up to eight feet in length with a short stubby tail. Average weight is around 500 pound and the height at the shoulder is between 30 and 43 inches.

Tapir BabyCredit: Wikimedia

It is dark brown with a low crest running down the neck. The ears are round and dark with white edges. The face is paler in colour. Young tapirs (see above) are born with stripes and spots. As well as being able to move quickly over rugged terrain, they are excellent swimmers and divers and will take to the water if frightened.

It is herbivorous tearing shoots, leaves, buds and small branches from trees and aquatic plants with its mobile snout. Their main predators are black caiman, jaguar and cougar.

The Amazon rainforest  has immense biodiversity and these are only a few of its more unusual inhabitants.