The Great ApesOverview: OrangutansOf the four species of Great Apes, orangutans are the least related to humans - they broke off from the common ape ancestor about 13 million years ago. In the wild today, orangutans are only found in Asia on two islands - Sumatra and Borneo. Each island has its own species of orangutan.
Orangutans are sexually dimorphic, with the males weighting about twice as much as the females. In the wild, a male orangutan weighs about 175-200 pounds, compared to females who weigh around 70-100 pounds. When in the trees, orangutans brachiate, but adult males are often too large to do this successfully because their weight breaks the tree branches. On the ground, orangutans walk quadrupedally. The orangutan diet is mostly frugivorous, but they also occasionally eat seeds, flowers, tree bark, and insects. Orangutans have been observed making simple tools, such as using sticks to get honey out of bee hives. Orangutans are unique among primates for their solitary nature. Young orangutans stay with mom for several years, but older orangutans generally move through the forest living alone. |
Overview: GorillasGorillas live in the wild in west and central Africa. Gorillas are the largest primate, with males weighing nearly twice as much as females. In the wild, a male gorilla averages 350-400 pounds, and a female about 150-200 pounds. Males can be up to 6 feet tall if standing bipedally, with arm spans of 9-10 feet. Unlike what you see in movies like Godzilla, gorillas are generally shy and peaceful animals who prefer to keep to themselves.
Gorillas climb in trees, although because of their size they spend a lot of time on the ground. They get around on the ground by knuckle-walking, a quadrupedal motion with the wrists turned under so the weight is on their knuckles rather than the palms of their hand. Gorilla communities usually consist of about 8-11 individuals, with only one adult male. This male is called the silverback, due to the graying of the hair on his back. The rest of the group consists of females with whom the silverback mates, and young children. Adolescent males are tolerated in the family group as long as they are not actively competing with the silverback for mates. When they are of age to mate, the males move on from the family and form bachelor groups. A bachelor gets to become a silverback in a group by fighting off or scaring off a dominant silverback and taking over his harem of females. |
Overview: Chimpanzees |
Overview: Bonobos |
Chimpanzees (also called chimps) are humans' closest relatives and are found in the wild in parts of central Africa. Chimps are comfortable in trees and also move quadrupedally on the ground.
Chimps are much smaller than gorillas - a male in the wild generally weighs between 90-130 pounds, and a female ways 70-100 pounds. Chimps do some hunting and have been observed eating small monkeys and prosimians in the wild, However, they are not very good hunters and about 90% of their diet is herbivorous. In the wild, chimpanzees live in groups ranging from 10-50 individuals. An alpha male controls the group and maintains order. He has dominant status over all other males in the group, which means he gets mating privileges (he gets to have sex with the females during their fertile times before any other males do). The alpha male is not necessarily the biggest chimpanzee - rather, chimps determine hierarchy based on social concerns, much like humans. The dominant male chimp must impress the others in the group and convince them to accept him as the leader. Chimp communities also have a female hierarchy; the dominant female in the group gets first access to food and resources over the other females. Males born in the community stay with the group; females move on when they reach mating age and find a new community to live with. Video 1: Gibbons |
Bonobos are closely related to chimpanzees and used to be called "pygmy chimps" (meaning "small chimps") before being acknowledged as their own species. In the wild, they live in Africa in a small territory of rainforest in the Democratic Republic of Congo.
Bonobos are slightly smaller than chimpanzees, with blacker hair tufts at the side of their face. Their bodies are slimmer than chimps', and their arms and legs are longer. They are not very sexually dimorphic - males average 85 pounds and females average 70 pounds. Bonobos do not hunt for meat; their diet is mostly frugivorous. Bonobos are more peaceful than chimpanzees. While chimps have been known to wage war with each other and kill over power and territory disputes, this behavior has not been observed in bonobos. Bonobos are far less aggressive. One theory for this is that bonobos are known for having frequent sex. Unlike most other primates, bonobos don't just have sex for making babies - like humans, they also use sex for pleasure . Bonobos use sex to relax and to prevent and resolve conflicts within the community ("make love, not war."). Bonobos engage in bisexual sex. Another unique characteristic of bonobos is that their societies are matriarchal. Females are more powerful in the community than males. Males derive their status from the status of their mother. |
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Video 2: Orangutans |
Video 3: Gorilla |
Video 4: Chimpanzees |