Orangutans, gorillas and common chimpanzees are mammals of the order Primates. The group of great apes they consist in also unites them. They have many anatomical similarities, but at the same time their social life and structure differs considerably. So, what are the differences in the social organization of orangutans, gorillas and common chimpanzees?
Unlike gorillas and chimpanzees, orangutans usually live alone, although adult females are not as solitary as males. Females normally live with their offspring for the first five or six years of their lives. They may keep in touch even longer. Sometimes orangutans prefer to live in communities but not in very close connection. Such communities consist of related families. Young orangutans appear to be very social, but not after they become adolescent. Adult males mostly live separately, being hostile to any other male. They stay with females only when its time for reproduction.
Orangutans are non-territorial and they do not force others out of their home ranges. Thus, home ranges often overlap. The home range usually includes adult male and sexually accessible females. When a female becomes pregnant, she remains sexually inaccessible for a couple of years, making male move to the other area. When males meet, there is a high possibility for them to be involved in a conflict, while females behave in friendlier way, especially when feeding.
Communication is a part of orangutan’s social life. Orangutans freely use vocal, visual and olfactory communication. Vocal communication includes long and fast calls to attract females, identify the territory, direct the members of the community when moving to a new place, threaten or express annoyance. Visual communication involves facial expressions, the whole body and the use of different objects to show aggressiveness, playfulness or calmness. Olfactory communication takes place through producing a musk.
Like orangutans, gorillas are not territorial either. They live in groups or troops including a few adult males, younger males, a couple of adult females and young. A regular group numbers up to 10-12 members. Home range of gorillas is usually bigger than that of orangutans. The leader of the group is the strongest and usually the oldest adult male. Unlike adolescent female orangutans, who keep close to their mothers and establish home ranges next to them, adolescent female gorillas switch to another group. They prefer to join a lone male gorilla or newly created group, since they will have more rights than if they join a long-created one. Adolescent male gorillas split from their parental troops and within a couple of years, they manage to create their own one.
Adult males or silverbacks are in charge of the group’s safety and this is why they tend to be more aggressive than other individuals are. They are also in charge of decision-making process, being in command of the entire group. Being a silverback demands to be strong and responsible, so it is not until the age of 15 that male gorillas create their own groups. Adult females stick to males rather than keep close to each other. They stay with their offspring for no longer than the first three or four years. Because of the competition for the females, conflicts within the group sometimes appear.
Common chimpanzees are highly social. They live in groups or communities. An average community is much bigger than those of orangutans and gorillas and numbers about 50 members. The communities are usually divided into smaller subgroups of up to 10 members. The membership is never stable, since chimps often switch to another group or decide to roam on their own. Nevertheless, even when they move, the bonds between family members remain very strong, especially the ones between mothers and daughters. When moved apart, family members contact with the help of special call. Generally, females stay together with their offspring for about 6-8 years. Males tend to stick to each other and behave like friends, while females keep aloof with their offspring from the others.
Adult male chimps dominate all the females. Both males and females have their own hierarchy. Age is the main factor defining the hierarchy position. There is one leader in a subgroup, who is usually in the age of 22-25. Such personal characteristics as strength, aggressiveness and even intelligence are also important though.
Unlike gorillas and orangutans, chimpanzees prove to be territorial primates. They are always prepared to defend their boundaries from intruders. Adolescent females who have never given birth are the only individuals welcome in any community. They may move to a new group forever or leave it once become pregnant.
In conclusion, orangutans, gorillas and common chimpanzees make up the group of great apes. Even though they are anatomically similar, their social organization differs a lot. Some of them are territorial and some are not, some are solitary and some are social, some group bigger communities and some smaller. There are also other differences that can be singled out.