Monkey Business
“whoop… whoop… whoop!” The
branches shake and dark objects scatter across the treetops. If you are standing
in the tropical forest you probably just heard monkeys over your head. Agile
and acrobatic monkeys easily leap through the forest but are often difficult
to see and study.
Most monkeys live in tropical regions in the Americas, Africa, and Asia and
spend much of their lives in treetops. Monkeys belong to a larger group of mammals called
primates. Primates have large brains, grasping hands and include lemurs,
apes and humans. Like other primates, monkeys are very intelligent and
curious and like you, have forward-facing eyes for great depth perception.
There are more species of monkeys than apes. Monkeys and apes are
both primates, just like humans. Can you tell which one is a monkey?
©G. Ellis/GLOBIO.org Old World and New World Monkeys
Monkeys are divided into two main groups:
Old World monkeys and New World monkeys. These groups have been evolving independently
from one another for millions of years.
Baby pigtail macaques may be taken by other adult females in the group.
All females in the group show great interest in infants, and higher-ranking
females often grab lower-ranking females’ infants.
©G. Ellis/GLOBIO.org Old World monkeys
Old World monkeys, such as mandrills and baboons, are native to Africa and
Asia. Old World monkeys live in a variety of different habitats, from grasslands
to rainforests to snowy mountain peaks. They can live in the trees or on
the ground. In general, Old World monkeys have:
- curved nostrils that are close together
- cheek pouches for storing food
- sitting pads on their rears
- tails that cannot grasp limbs and trees
Black handed spider monkeys eat a lot of food over a short period of time
and they like to eat while hanging, climbing or moving. Using their
prehensile tails to swing through the forest, spider monkeys can move very
fast.
©G. Ellis/GLOBIO.org New World monkeys
New World monkeys live in South and Central America and Mexico mostly in
the trees in tropical rainforests. In general, New World monkeys have:
- nostrils that are far apart
- no cheek pouches
- no sitting pads on their rears
- prehensile tails, which can grasp limbs and trees.
Largest and Smallest Monkeys
The face and rear of the male mandrill can become brighter in color when
excited. It becomes more colorful as they get older. Their blue, red
and purple face and rear can help to identify one another when searching
for food.
©Vincent van Dam Baboons and mandrills weigh in as some of
the largest in the monkey world. Both of these Old World monkeys live in Africa.
The males weigh up to 30-36
kg. Their primary predators are human beings, who hunt them for food. Mandrills
are endangered because of this hunting.
The smallest monkey species is
the pygmy marmoset, which is a New World monkey. Adults weigh 113
to 119 g. Pygmy marmosets are found in the tropical
rainforest in the upper Amazon basin in South America. They live mostly
in trees and are active during the day. They are not currently endangered.
However, scientists are concerned about their population because pygmy marmosets
are increasingly being sold as pets.
Breeding
During the first month of life, baby olive baboons nurse and sleep frequently
with their mother. As they get older, olive baboons play by themselves
or with their peers and they will become more active.
©G. Ellis/GLOBIO.org Pregnancy and
birth in monkeys varies by species. The pygmy marmoset lives in a group of
six. Only the dominant female
in the group has babies. Offspring are
often fraternal twins--the kind of twins that don’t look exactly alike.
After birth, the offspring are carried around by the males in the community.
They are returned to the mother for nursing.
Squirrel monkeys are also New World monkeys, but they have different birth
habits. After birth, the newborn clings to its mother’s back rather than
being carried by males. Other female squirrel monkeys, rather than males, share
newborn care with the mother.
Lifespans
The lifespan of monkeys depends on the species. In the wild, squirrel monkeys
can live up to 20 years. Squirrel monkeys spend their lives in trees and are
vulnerable as prey for eagles.
Howler monkeys live 15 to 20 years in the wild. Howler monkeys have been hunted
and their habitats have been destroyed. This greatly decreases the lifespan
of the species. Mandrills live up to 45 years in the wild. They are also hunted
for food.
Monkey Anatomy
Monkeys have bodies that are similar in a
lot of ways to our own, with arms, legs, and thumbs that can move easily. They also have flexible arms and legs for grasping and climbing. But you might be surprised that they can not swing through the branches. Only apes and humans can swing from trees, monkey’s shoulders are not designed to allow for swinging.
Old
World and New World monkeys look considerably different, as you can see below.
Baboons are Old World monkeys and capuchins are New World monkeys.
Click on the picture to learn more.
Groups Called Troops
An olive baboon troop, or group, forages for food. Troops of olive baboons
are mostly made up of females and their young, but include a few males.
©G. Ellis/GLOBIO.org Many species of monkeys live in groups called
troops. Troops allow monkeys to protect themselves from predators, such as
humans. In Africa, mandrills can live in troops of up to 45 monkeys. Mandrill
troops are led by a dominant male, which has the brightest colors on his face--and
also on his rear! The troop also includes several breeding females and their
offspring. Western red colobus monkeys live in troops of up to 80 monkeys.
The large size of their troops helps protect them from the humans and chimpanzees
that hunt them for food.
Communication
Vocal and visual communication is important to olive baboons. In the
most stressful situations “screams” can be sounded, as a high-pitched
and continuous vocalization. These can be a response to intense emotions
of pain, fear, or aggression.
©G. Ellis/GLOBIO.org Monkeys communicate with hand gestures, facial expressions, and noises called
vocalizations. Vocalizations can
be quite complex and are often used to warn other monkeys of predators. Mother
monkeys can distinguish the vocalizations of their own infants from other babies.
There is also evidence that suggests that some monkey species have developed
rules for putting together phrases.
Staring is thought to be a threat in monkey communities. Staring is often
followed by looking away if confrontation is to be avoided. Showing of teeth
is often also interpreted as a threat.
Here Comes the Groom
Monkeys form relationships with other monkeys in their species in different
ways. They bond with one another by grooming. They check each other for parasites and
clean themselves. They also bond by eating and sleeping close to one another.
What’s for Dinner? Everything!
The pygmy marmoset uses its teeth to poke holes in certain trees and vines.
Sixty-seven percent of their feeding time is spent eating tree gum or preparing
new food sources by gnawing tree trunks or large branches.
©David Lewis Monkeys are omnivores.
This means they eat a variety of different foods. Many species of monkeys eat
fruits, seeds, roots, herbs, and insects.
Some monkeys eat very particular types of foods. Pygmy marmosets drill holes
in trees and drink the tree sap, called gum. They’ll also eat insects,
lizards, spiders, and fruit. Diets of monkeys are so full of variety that in
a year a monkey may eat 200 different things!
Monkeys Threatened
The greatest threat to monkeys is the loss
of habitat.
Often the building of roads and the logging of forests destroys the areas monkeys
use as homes. Without places to live, monkeys are more vulnerable to predators,
including human beings who hunt monkeys for food. By focusing on environmental
education and preserving habitats as well as making laws to protect monkeys,
species including the mandrills, brown spider monkey, and red colobus
monkey, may be spared extinction.
White-faced capuchins are important to the rainforest because they disperse
seeds and pollen so new plants can grow. Why do you think new plant
growth is important for monkeys to survive?
©G. Ellis/GLOBIO.org