Black-capped squirrel monkey (Bolivian)

Appearance

Black-capped squirrel monkeys owe their name to the markings surrounding their face. These markings resemble a skull, with a dark spot around their mouths and light circles around their eyes. You may also recognize black-capped squirrel monkeys by the dark “cap” on the top of their heads. Their fur is yellow, with gray areas on their shoulders. Their long, yellow tail helps them maintain balance. Furthermore, these animals have scent glands on their chest, genitals, and around their anus. Using these glands, squirrel monkeys leave their scent on branches and trees, marking their territory for other animals to recognize.

Habitat

In the wild, black-capped squirrel monkeys live in Bolivia, Peru and Brazil (South-America). There they live in the tropical rainforests and mangrove woods. 

Lifestyle 

Black-capped squirrel monkeys are extremely social animals. They live in large groups ranging from 20 to 100 individuals. These groups are divided into subgroups consisting of mothers, sisters, and (grand)daughters. There is a clear hierarchy within the group: a single adult female leads the group. The ranking of the other members is determined by their individual characteristics and the number of offspring a female has. Most of the time, the males have little influence. They often live on the outskirts of the group, venturing out to explore when danger is near and warning the others if needed. However, during the mating season, the roles are reversed. During this period, the males rise significantly in rank and are fully permitted to mate with the females as they desire.

Behaviour

Black-capped squirrel monkeys use about 20 different sounds to communicate with each other, sounding similarly to the chirping of birds. They also use different kinds of facial expressions to clarify things to each other. Next tot that, these animals communicate through smell. To do this they make use of the scent glands on their bodies. For example, they rub their chest against certain objects to leave their scent behind and mark their territory. Squirrel monkeys also parttake in “urine-washing”: they lather their hands and feet in their own urine and leave that scent behind on the branches and trees that they touch.

Reproduction 

Black-capped squirrel monkeys have a dedicated mating season, that usually takes place around the fall. During this period, the adult males grow significantly in a short amount of time. They are able to store water in between their muscles, making them appear like real bodybuilders with broad shoulders. They also give off a special smell, which the females find extremely attractive. Up next, plenty of mating occurs. The babies are usually born around spring and summer. And they’re not the lightest ones: on average, they weigh around 100 grams at birth already. A fully developed female weighs around 700 grams. You can compare this to a human mother giving birth to a baby of over 10 kilos! Therefore it’s quite heavy for the mothers to carry the baby with them, so most of the times they wear them on their backs. The other sisters, aunts and grandmas in the group will also occasionally take care of the offspring. The men do not interfere with the upbringing. After a few weeks the younglings are already walking their first steps. They still drink from their mothers untill up to about six months. They are fully independent after about a year and are completely developed and therefore reach their adult stage at 3 to 4 years old. The adult males leave their birth group when developed, while the females stay in the group in which they were born. 

Group dynamics

It is quite heavy for the mothers to continuously bring along the little ones, so they’ll carry them on their backs. And other sisters, aunts and grandmothers in the group will also take care of the offspring from time to time. Newborns will walk their first steps after just a few weeks. They will keep breastfeeding for around the first 6 months. They are independent after a year and classify as an adult after 3 or 4 years. Adult males will depart from their birth group, while the females stay. 

Situation in the wild

Black-capped squirrel monkeys are not endangered in the wild. However, large parts of their habitat are disappearing due to deforestations. 

At Apenheul

The black-capped squirrel monkeys in Apenheul roam free among guests. It’s a large group of animals, that consists of multiple subgroups. The larger the subgroup, the more power it holds. This can also be seen clearly in Apenheul. The largest group of black-capped squirrel monkeys in a zoo lives here in Apenheul. Even within Apenheul, the black-capped squirrel monkeys are the largest monkey group that can be spotted in the park. 

Population management programme 

Apenheul is a part of the European endangered species programme (EEP) for black-capped squirrel monkeys. By working together with other international zoos, we maintain a genetically healthy and demographically stable population of this species in zoos that serves as a reserve population.

Fun facts 

• Living in a large group has plenty of advantages. In such groups there are plenty of eyes that can pay close attention, so you’re much stronger against predators by working together. 
• Black-capped squirrel monkeys spend a large part of their day busy with searching for food. 
  They catch insects, spiders and frogs with their hands at lightning speed, sometimes even robbing a bird’s nest. They also often flip leaves around to check if there is a snack behind them. How smart!