Howler monkeys live in family groups. They spend most of their time on tree tops. They have strong arms and legs that help them swing from tree to tree.

They also have special tails that can be used to grip on to branches - just like having an extra arm. Howler monkeys are so strong that they can hang from a branch while holding on only by their tail. They are vegetarian. Their favourite foods are fresh tree leaves, especially young leaves that grow on tree tops.

Sometimes howler monkeys will also eat fruit, flowers, and nuts. Some scientists think that howler monkeys might also eat bird eggs if they find a nest.

Why they howl

Howler monkeys yell at dusk and dawn. This is also the time when they are awake, and when they go and look for food.

As there are often different family groups living in the same area, scientists think that these loud noises are threats to other monkeys. A loud howler yell is a warning to keep away.

Howlers also live in tree tops where it is quite easy to lose sight of one another. Scientists believe that howler monkeys also use their loud voices to tell each other where they are.

Finally, howler monkeys also shout to warn each other about danger. If these monkeys see a person on the ground, or a jaguar in the trees, they yell warnings to their friends.

Loudness is measured in decibels. The louder the sound, the more decibels.

See how loud howler monkeys are by checking this list:

A ticking watch: 20

Normal conversation: 60

City traffic: 70

An alarm clock: 80

Howler monkey: 90

A chain saw: 110

Jet engine: 130

Fab fact

There are no special names for male and female monkeys - they're just called monkeys. However, baby monkeys are called infants.

A group of monkeys is called a troop or a tribe.

If someone is like a monkey, you say they are simian, which is pronounced sih-me-yan.

Fab fact

Howler monkey gods were worshipped by the Maya, a tribe that once ruled an empire in Central and South America. The howler monkeys were the gods of the arts, especially dancing and music.

When a monkey shows you all its teeth, it isn't smiling. Monkeys show their teeth as a warning that they are going to bite - and they can bite really hard.

The Guatemalan black howler is the biggest of the howler monkeys. Males can be 64cm tall, with a 69cm long tail, and weigh more than 11kg.

The biggest howler monkey is endangered owing to forest destruction. Also, people hunt this animal for its meat and to sell infants as pets.

World's noisiest and laziest monkey

Howler monkeys get up just before dawn and eat. Then they rest in the trees all day long.

At dusk, they eat again. And then they go to sleep for the night.

Howler monkeys rest and sleep about 18 hours each day. They are the laziest monkeys in the world!

Why these animals make terrible pets

Poachers kill adult howler monkeys, steal their infants, and sell them as pets. However, these animals make terrible pets.

Howler monkeys eat only very fresh leaves - and lots of them. Getting a good supply of leaves can be very difficult. They also need to live in groups and become aggressive and depressed if they are alone. Can you imagine what your neighbours would say if you had a pet that screamed for an hour every morning and an hour every night?