Black-capped squirrel monkey

Appearance

Small in size, 25-35cm long plus a long tail measuring up to 45cm. Squirrel monkey fur is short and close, colored black at the shoulders and yellowish orange on its back and extremities. Their throat and the ears are white and their mouths are black. The upper part of their head is hairy. This black-and-white face gives them the name "death's head monkey" in several Germanic languages (e.g., German Totenkopfaffen, Swedish dödskalleapor, Dutch doodshoofdaapjes) and Slovenian (smrtoglavka).

Naming

*Bolivian squirrel monkey, "Saimiri boliviensis boliviensis"
⤷ Peruvian squirrel monkey, "Saimiri boliviensis peruviensis"
Geoffroy and Blainville 1834

Distribution

Tropical forests of South America

Status

Least Concern, although they are captured for the pet trade and medical research. Loss of habitat is also a risk.

Behavior

Diurnal and arborial, they travel in the canopy of the forest but occasionally come to the forest floor for feeding.
Like most of their New World monkey relatives, squirrel monkeys are diurnal and arboreal. Unlike some other New World monkeys, their tail is not used for climbing, but as a kind of "balancing pole" and also as a tool. Their movements in the branches can be very rapid.

They live together in multi-male/multi-female groups with up to 500 members. These large groups can, however occasionally break into smaller troops. They have a number of vocal calls, including warning sounds to protect themselves from large falcons, which are a natural threat to them. Their small body size also makes them susceptible to predators such as snakes and felids. For marking territory, squirrel monkeys rub their tail and their skin with their own urine.

Habitat

Dense tropical forests

Reproduction

The mating of the squirrel monkeys is subject to seasonal influences. Females give birth to young during the rainy season, after a 150- to 170-day gestation. The mothers exclusively care for the young. S. boliviensis are not fully weaned until 18 months old. Female squirrel monkeys reach sexual maturity at age 2–2.5 years, while males take until age 3.5–4 years old. They live to about 15 years old in the wild, and over 20 years in captivity. Menopause in females probably occurs in the mid-teens.
During the mating season, males can almost double in size by way of water retention and other factors, they do this in order to attract females, showing themselves to be healthy, strong and suitable for fathering their offspring.
It is not unusual for the males to gang-rape females.

Food

Omnivorous, consuming plants and insects.

Predators

Snakes, birds of prey and other mammalian predators.

Defense

Living in large groups gives them a better defense than solitary animals. They have a wide range of vocalisations to warn the rest of the group of predators. If threatened they may often attack the predator, screaming and biting.

Evolution

The crown lineage of the extant squirrel monkeys appears to have diverged around 1.5 million years ago. S. boliviensis appears to be the first diverging species in the group. S. oerstedii and S. s. sciureus, are sister species. S. s. macrodon is the sister species to the S. oerstedii / S. s. sciureus clade.

Uses

Captured for the pet industry and also for medical research