Squirrel Monkey Facts

Squirrel monkey belongs to the New World Monkey order and it is quite different from the Old World monkeys in that it has wide open nostrils that are open to the side. The squirrel monkey displays round head with large eyes facing forward. They are classified into two groups; Gothic (pointed) and Roman (rounded).

Physical Characteristics

The head-and-body length of squirrel monkeys is 10.8–14.6 in (27.5–37 cm); with the tail length of 17.8 in (36–45.2 cm).
The average weight measures around 1.2–2.75 lb (0.55–1.25 kg).
The squirrel monkeys have rounded muzzles that are not much prominent from the face.
They have small slender bodies. The adult males are larger than female monkeys.
They have dense short fur that prevents them from extreme temperatures.
The squirrel monkeys show different coat colors in that some appear to be black while others are gray.
The crown of the head is black or gray while its muzzle is absolute black.
They have yellowish golden to reddish back while the shoulders are gray to olive in color. They have yellow forearms, hands, and feet.
The squirrel monkeys are also distinguished by their white to yellow undersides.
They have thick hairy tail which is nonprehensile. As in capuchin monkeys, the tails are longer than their body size.

Squirrel Monkeys ©www.thinglink.com

Distribution

Squirrel monkeys are known to live in the northeastern Brazil, Amazon basin, from central Columbia to Bolivia.
In the northeastern Brazil they are typically found in French Guiana, Peru, Ecuador, Suriname, Guyana, and Venezuela.

Habitat

Squirrel monkeys build homes in a variety of habitats ranging from primary to secondary forests, riverine forests, high and lowland forests, palm forests, low canopy hillside, marsh places, mangrove forests and swamps.
Their habitats are usually found at an altitude of 6,500 ft (2,000 m) above sea level.

Behavior

Like capuchin monkeys, Squirrel monkeys are not only diurnal but arboreal by nature. They are often found moving (sometimes flying) across the trees.
There are around 10 – 55 individuals in each group in the wild. It consists of multimale and multifemale monkeys and the group can go up to 300 individuals.
Nonetheless, smaller groups are usually preferred as it helps in foraging during the day. They all get together at night.
The adult females are known to dominate the adult males but in the breeding season it is the other way round.
Squirrel monkeys do not hesitate to speak and they communicate both vocally and visually. They give loud calls especially when carnivorous mammals, birds of prey or boas arrive. These monkeys are extremely responsive to any external threat. Harpy eagles commonly prey young squirrel monkeys which is why they have unique alarm calls being directed towards harpy eagles.
The calls may be in the form of barking with varied frequency but at least it signals their other group members to remain alert as the eagle is coming.
Squirrel monkeys are able to give more than 24 different vocalizations including the call which they give in order to find out their members.
In visual signals, they typically show their genitals by extending their one leg outward. It is also a behavior to show dominance.
Unlike in capuchin monkeys, squirrel monkey females do not groom their infants with the exception of few. Squirrel monkeys believe in self-grooming.

squirrel monkey facts — Squirrel Monkeys ©www.woburnsafari.co.uk

Feeding Ecology and Diet

Squirrel monkeys are largely frugivorus and insectivorous. They must take food rich in proteins and they achieve this by eating animal prey.
However, the essential portion of the diet is composed of fruits especially flowers, seeds, nuts, insects, leaves, crabs, spiders, gum, and buds.
They are also known to consume smaller vertebrates such as frogs and bats.
Sometimes they overlap with the capuchin monkey’s range. Both of them share their food sources.
Squirrel monkeys consume most tree branches (especially tips); they have a light weight that enables them to sit on lighter branches.
Squirrel monkeys found in Panama are more apt to spend almost 95% per cent day time in foraging and traveling.

Reproductive Biology

Squirrel monkeys involve in breeding for 2 to 3 months yearly. The young are born in the corresponding 2 to 3 months.
The birth season lasts 5.5 – 6 months—a time when food is also available in large quantity. The birth takes place in wet season.
The adult males become 10 – 30% heavier in the breeding season. The weight typically shifts to the upper body. It is a unique physiological change. These males are called ‘fatted males’.
The female will continue to mate for about 12 – 14 days.
The gestation period lasts 150 – 180 days.
Females become mature at 3 years while males reach the maturity at 5 – 6 years of age.
The average weight of an infant is 3.2–3.9 oz (90–110 g) at birth.
These infants would stick to their mother’s back from day one. When the infant becomes 3 – 4 weeks old, its mother will hand over to the other childless mother to look after her child. That is not to say that her mother will leave her child. The mother continues to keep an eye on her young almost all the time.
The infants are going to be weaned in five-month time and they will feel independent by 11 – 12 months—a period when her mother is ready to give birth again. There is still close relationship between the mother and a child.

Conservation Status

Over the period of time squirrel monkeys had faced numerous challenges in the form of habitat loss, degradation and illegal export to other countries.
The International Union for the Conservation of Nature (IUCN) has listed one of the species (S. o. citrinellus) as critically endangered while one of the subspecies Saimiri oerstedii as endangered.
During the early 1960s and 1970s more than 25,000 squirrel monkeys had been exported from Peru to the rest of the world.

References

Hershkovitz, Philip. “Taxonomy of Squirrel Monkeys genus Saimiri (Cebidae, Platyrrhini): A Preliminary Report with Description of a Hitherto Unnamed Form.” American Journal of Primatology 6, no. 4 (1984): 257–312.

Vermeer, Jan. The Nutrition of Squirrel Monkeys (Saimiri): Report of an EEP-Survey. Romagne: La Vallee des Singes, 2000. Kenneth

Rylands, Anthony B., et al. “An Assessment of the Diversity of New World Primates.” Neotropical Primates 8, no. 2 (2002): 61–93.