Monkey

## A barrel of monkeys

They’re magnificent, mischievous, and sometimes mysterious - monkeys! They have many different adaptations, depending on their habitat. Most are arboreal. Others, like macaques, baboons, and some mangabeys, are more terrestrial. All monkeys can use their hands and feet for holding on to branches, but some arboreal monkeys can use their tails, too. Tails that can grab and hold are called prehensile. These special tails are ridged on the underside and very flexible, so much so that they can grab a tree branch or pick up something as small as a peanut!

## Old World or New World?

Monkeys are found in two main regions of the world, so scientists have grouped them as either Old World monkeys or New World monkeys. Old World monkeys are found in Africa and Asia. Some examples are guenons, mangabeys, macaques, baboons, and colobus monkeys. New World monkeys are found in Mexico, Central America, and South America. Some examples are woolly monkeys, spider monkeys, howler monkeys, capuchin monkeys, and squirrel monkeys. Marmosets and tamarins also live where New World monkeys are found but are different enough to be in their own different scientific grouping.

There are a few characteristics that are different between the Old World and New World monkeys:

### Noses

Most Old-World monkeys have small, curved nostrils set close together. Most New World monkeys have round nostrils set far apart.

### Cheek pouches

Macaques and some of the other Old-World monkeys have cheek pouches, where food is stuffed on the run so it can be chewed later. New World monkeys don’t have cheek pouches.

### Rump pads

Some Old-World monkeys, such as drills, have sitting pads on their rumps, but New World monkeys do not.

### Tails

Some New World monkeys, such as spider monkeys, have prehensile tails, but Old-World monkeys do not. And one Old World monkey species, the Barbary macaque, has no tail at all!

## At home

Most monkey species live in the tropical rain forests of Asia, Africa, Central and South America, or the savannas of Africa. Geladas and golden monkeys are mountain dwellers, and Japanese macaques live in parts of Japan where it snows; these are the monkeys you may have seen on TV that find hot springs and spend a lot of time in the winter sitting in the warm water - kind of like a macaque Jacuzzi! Baboons live in savannas, open wooded areas, and rocky hillsides; although they are able to climb trees, they spend most of their time on the ground.

## Getting around

Many monkey species are known for their tree-swinging leaps that put human acrobats to shame! Many monkey species use the “arm over arm” technique you may have seen children practicing on the “monkey bars” at the playground! Colobus monkeys, unlike other monkey species, have hind legs that are much longer than their forelimbs, making for incredible leaping ability with great speed.

Monkey feet are as flexible as their hands, which also help them travel through small branches high up in the rain forest canopy. Monkeys play an important role in the wild by pollinating flowers and dispersing seeds as they travel. Some monkeys can swim; their webbed toes help them paddle through the water, and they may swim across a stream or river to avoid predators or get to food.

Night or owl monkeys are strictly nocturnal, using their enormous eyes to see well in the dark. They communicate with one another through scents and calls, including a series of grunts that resonate in the forest.

## A huge menu

Prehensile tails come in handy for holding on while the monkey collects food: flowers, fruits, nuts, leaves, seeds, insects, birds’ eggs, spiders, and small mammals. Old World monkeys fill up their large cheek pouches with fruits, leaves, and insects as they forage during the day, stopping to chew and swallow their food when they find a safe spot to rest. Baboons are also known to eat meat when they can catch it, including young antelope, rabbits, and birds like guinea fowl.

Leaves are the food of choice for some monkey species. Colobus monkeys and langurs have chambered stomachs that carry bacteria, which help ferment and digest leaves. Geladas prefer to graze on grass!

Monkeys at the San Diego Zoo and the San Diego Zoo Safari Park are offered a variety of vegetables, special herbivore biscuits, and a variety of leafy branches (mulberry, willow, hibiscus, and ficus) to munch on.

## We like company!

Groups of monkeys, called troops, travel together by day to find food. A troop can number from few a few individuals to a thousand or more, depending on the species.

Within huge troops, the animals form smaller groups, called harems, which include an adult male, several adult females, and their offspring. Unattached adult males, called bachelors, may form their own group. To keep family bonds, monkeys engage in daily mutual grooming.

One exception to social living is the gray titi monkey, native to the tropical forests of Bolivia. These small monkeys, which only weigh about 2 pounds (0.9 kilograms), live in small, monogamous family units made up of the parents and their immature offspring.

## Read my life

Monkeys are very social animals, so it is important that they communicate well in order to get along in their large groups. They use vocalizations, facial expressions, and body movements to get their messages across. Staring, for instance, is a threat in monkey society. Monkeys look down or away to avoid threatening other monkeys, thus preventing fights. Species with long tails use them to “talk to others and indicate their mood. Loud vocalizations can mean, "stay out—this is my territory.” Using vocalizations instead of fighting is a much safer way to communicate. Monkeys use barks, screams, grunts, squeaks, hoots, wails, and moans to communicate with one another.

Grinning, or pulling the lip up to show the teeth, may seem like a smile to us. But for monkeys, this is a sign of aggression or anger, because biting is one of the ways monkeys fight and defend themselves. Other signs of aggression include head bobbing, yawning (again, to show the teeth), and jerking the head and shoulders forward. Cotton-topped tamarins raise and lower a crest of fluffy white hair on their head to emphasize their facial expressions.

Monkeys also express affection and make peace with others by grooming each other. Although grooming helps monkeys keep their fur clean of dirt, dead skin, and parasites, it also helps them build and maintain good social relationships. Grooming seems to be a way to make up after fighting or to make friends with other troop members.

## Baby life

Some monkey species give birth to babies that are a completely different color from the parents. For example, adult colobus have black hair, but a newborn is white; langur babies are orange while their parents are buff or brown. It’s thought this color distinction makes it easier for the whole troop to identify and look after the infants. The youngster’s color usually changes within the first six months, when the juvenile becomes an almost perfect copy of the adults.

Infants are helpless at birth, so they get rides by clinging to their mothers. But marmosets and tamarins are different - the fathers have almost all the responsibility! They carry the babies on their back and watch over them, only giving them to Mom for nursing. Another difference - they regularly have twin or triplet, not single, births. Is that because Dad helps out so much?

When the troop is not traveling, monkey babies are very active, spending much of their waking hours playing. These fun activities help young monkeys develop physical and social skills they need for adult life.