Chimpanzee

The chimpanzee (/ˌtʃɪmpænˈziː/; Pan troglodytes), also simply known as the chimp, is an endangered species of great ape native to the forests and savannahs of tropical Africa. It has four confirmed subspecies and a fifth proposed one. When its close relative, the bonobo, was more commonly known as the pygmy chimpanzee, this species was often called the common chimpanzee or the robust chimpanzee. The chimpanzee and the bonobo are the only species in the genus Pan.

The chimpanzee is covered in coarse black hair but has a bare face, fingers, toes, palms of the hands, and soles of the feet. It is larger and more robust than the bonobo, weighing 40–70 kg (88–154 lb) for males and 27–50 kg (60–110 lb) for females and standing 150 cm (4 ft 11 in). Evidence from fossils and DNA sequencing shows that Pan is a sister taxon to the human lineage and is thus humans' closest living relative. The chimpanzee genome contains coding regions for 18,759 proteins which is within ten percent compared to 20,383 proteins for humans.

The chimpanzee lives in groups that range in size from 15 to 150 members, although individuals travel and forage in much smaller groups during the day. The species lives in a strict male-dominated hierarchy, where disputes are generally settled without the need for violence. Nearly all chimpanzee populations have been recorded using tools, modifying sticks, rocks, grass and leaves and using them for hunting and acquiring honey, termites, ants, nuts and water. The species has also been found creating sharpened sticks to spear small mammals. Its gestation period is eight months. The infant is weaned at about three years old but usually maintains a close relationship with its mother for several years more.

Etymology

The name "chimpanzee" was first used in 1738 in The London Magazine, where it meant "mockman" in a language spoken by people in Angola. The shorter word "chimp" came about in the late 1870s.

The scientific name for chimpanzees, Pan troglodytes, has parts that come from ancient stories. "Pan" is the name of a Greek god, and "troglodytes" refers to a mythical group of people who lived in caves.

Taxonomy

The chimpanzee was first recognized in the 17th century. Early scientists studied both chimpanzees and their close relatives, the bonobos. By the late 1700s, German naturalist Johann Friedrich Blumenbach classified the chimpanzee as Simia troglodytes. In 1816, another German naturalist, Lorenz Oken, introduced the genus Pan.

Chimpanzees, along with humans, belong to the Hominidae family, also known as the great apes. This family includes orangutans, gorillas, chimpanzees, bonobos, and humans. Studies show that chimpanzees and humans share a common ancestor and have very similar DNA, differing by only about 1.2%. Despite these similarities, chimpanzees have 24 pairs of chromosomes, while humans have 23 pairs due to a fusion event in human evolution.

Characteristics

Adult chimpanzees stand about 150 cm (4 ft 11 in) tall on average. Males usually weigh between 40 and 70 kg (88 and 154 lb), while females weigh between 27 and 50 kg (60 and 110 lb). They have long arms that can reach below their knees, and their hands and feet are made for grasping. Their faces are rounded with forward-facing eyes and prominent brow ridges.

Chimpanzees are covered in coarse hair except on their faces, hands, and feet. Their hair is usually black but can be brown or ginger, and may turn white or grey with age. They are strong climbers and can walk on all fours or on two legs. Their brains are smaller than human brains but are built for quick actions rather than complex thinking.

Ecology

The chimpanzee is a very adaptable animal. It can live in many types of habitats, including dry savanna, evergreen rainforest, montane forest, swamp forest, and woodland. Chimpanzees build a new sleeping nest in a tree each night and usually sleep alone, except for babies and young chimpanzees who stay with their mothers.

Chimpanzees eat a variety of foods but prefer fruit. They also eat leaves, seeds, blossoms, stems, and even some insects and small animals. However, fruits and other plant foods make up most of what they eat. Their diet can change depending on what food is available and where they live.

Behaviour

Chimpanzees have been studied for their group living, mating, parenting, communication, and hunting. They live in communities of up to 150 members, but usually travel in smaller groups. These groups can include any mix of ages and sexes, and both males and females sometimes travel alone. Males stay in their birth community, while females usually leave when they are older. Males are usually dominant over females and have a hierarchy among themselves.

Chimpanzees communicate using facial expressions, sounds, and body postures. They use special faces and sounds to show fear, play, or submit to others. They also make calls to keep in contact with their group and to signal danger or food. Hunting is a group activity for males, while females often hunt alone. Chimpanzees work together to catch monkeys, with each member having a specific role in the hunt.

Intelligence

Further information: Primate cognition

Chimpanzees show many signs of intelligence. They can remember symbols, use tools, and work together. They have passed the mirror test, which suggests they recognize themselves. Chimpanzees can even remember things after a long time without seeing mirrors. They use insects to heal wounds and show behaviors that look like culture, such as different ways of grooming or using tools.

Chimpanzees can learn to recognize numbers and remember quick flashes of digits. One chimpanzee named Ayumu was very good at this task, doing better than human adults in some tests. They also show laughter-like sounds when playing or being tickled, especially in areas like the armpits and belly.

Tool use

Further information: Tool use by animals

Almost all chimpanzee groups use tools. They change sticks, rocks, grass, and leaves to help catch food like termites, ants, nuts, and honey. Some chimpanzees have used stone tools for over 4,000 years.

One famous chimpanzee modified a twig to get termites from their homes. Others use sticks to get honey from beehives, and some use leaves to drink water. In West Africa, chimpanzees sharpen sticks to catch small animals from tree holes.

Speech and language

Main article: Great ape language

Scientists have tried to teach chimpanzees human language. One chimpanzee named Washoe learned many signs for things. Another chimpanzee named Nim Chimpsky was taught signs too, but later studies showed he mostly copied what humans did and did not truly understand language like humans do.

Human relations

Chimpanzees have appeared in many cultural traditions and forms of entertainment. Some African groups, like the Gio people of Liberia and the Hemba people of the Congo, create chimpanzee masks for teaching and rituals. In Western media, chimpanzees are often shown as playful companions or sidekicks, like Judy on Daktari and Darwin on The Wild Thornberrys. They have also starred in science fiction stories and films, such as Conquest of the Planet of the Apes, where a chimpanzee leads a revolt against humans.

Chimpanzees have also been kept as pets, especially in parts of Africa, though this can be dangerous due to their strong and sometimes aggressive nature. Some chimpanzees have been used in scientific research, where they have helped us learn more about health and disease. Famous studies, like those by Jane Goodall at Gombe Stream National Park, have taught us much about chimpanzee behavior and social lives. These studies show that chimpanzees have complex emotions and strong bonds with each other.

Conservation

The chimpanzee is listed as an endangered species. There are thought to be between 172,700 and 299,700 chimpanzees left in the wild, much fewer than the about a million that lived in the early 1900s. They are protected by laws in most places and live both inside and outside national parks.

The biggest dangers to chimpanzees come from losing their homes, poaching, and diseases. Their forests are shrinking because of deforestation and road building, which also makes it easier for poachers to reach them. Sadly, some people hunt chimpanzees for food, known as bushmeat, or take them for pets. Diseases are also a serious problem because chimpanzees and humans are very similar and can catch many of the same illnesses.