How did our evolutionary ancestors make sense of their world?
Researchers at Max Planck Institute compared the five species of great apes --- orangutans, gorillas, bonobos, chimpanzees, and humans. The study was published in Current Biology journal. They tried to establish which cognitive strategies they prefer in order to uncover hidden characteristics. The scientist applied a technique called comparative psychological research. They found that some of the strategies shaped by evolution are evidently masked very early on by the cognitive development process unique to humans.
Orangutans is a species (Pongo pygmaeus, family Hominidae) of arboreal great ape, found only in the lowland swamp forests of Borneo and Sumatra but originally in the tropical forests of South Asia as well.
The orangutan (Malaysian for “person of the forest”) has a short thick body, long arms, short legs, and shaggy reddish hair. Males are about 4.5 ft (137 cm) tall and weigh about 185 lb (85 kg); females are smaller. Orangutans are placid, deliberate, ingenious, and persistent. Males have flat, fatty cheek pads and a baglike, pendulous swelling at the throat. Orangutans use all four limbs to walk and climb. They eat mostly figs and other fruits and some leaves, bark, and insects. They sleep in trees on a platform built of interwoven branches. Adults are solitary and live far apart, coming together only for a brief courtship. The mother carries and nurses the single young for almost three years. Though generally silent, the adult male has a loud, roaring “long call.” The orangutan is an endangered species.
Bonobo is a species (Pan paniscus) of great ape. It was once considered a subspecies of the chimpanzee, which it closely resembles in size, appearance, and way of life. Its range, the lowland rainforests of central Congo (Kinshasa), is more restricted than that of the chimpanzee, and it has longer, more slender arms, a more slender body, and a less protruding face. Bonobos eat mainly fruits but also leaves, seeds, grass, and small animals. They form communities of 50–120 individuals. A striking feature of their social lives is that they engage in sexual activity with great frequency, often as a means of settling quarrels, and with little regard for gender or age. Populations are shrinking, largely because of hunting and habitat destruction, and bonobos are an endangered species.
Gorilla is the largest of the great apes. A stocky, powerful forest dweller native to equatorial Africa, the gorilla (Gorilla gorilla) has black skin and hair, large nostrils, and prominent brow ridges. Adults have long, powerful arms; short, stocky legs; an extremely thick, strong chest; and a protruding abdomen. Adult males have a prominent crest on top of the skull and a “saddle” of gray or silver hairs on the lower part of the back. Males, about twice as heavy as females, may reach a height of about 5.5 ft (1.7 m) and a weight of 300–600 lbs (135–275 kg). Gorillas are mainly terrestrial, walking about on all four limbs. They live in stable family groups of six to 20 animals that are led by one or two silverbacked males. They eat leaves, stalks, and shoots. They are unaggressive and even shy unless provoked. They are calmer and more persistent than chimpanzees; though not as adaptable, gorillas are highly intelligent and capable of problem solving. The gorilla is hunted for its body parts and meat, and its habitat is disappearing. It is an endangered species throughout its range; the mountain subspeciesis critically endangered.
Chimpanzee is species (Pan troglodytes) of great ape that inhabits the rain forests and woodland savannas of equatorial Africa, the closest living relative to humans.
Chimps are 3–5.5 ft (1–1.7 m) tall when standing upright, weigh 70–130 lbs (32–60 kg), and have a brown or black coat and a bare face. They do most of their feeding in the trees, swinging from branch to branch; to move any distance they walk, usually on all fours, on the ground. They eat mostly fruits, berries, leaves, and seeds, some termites and ants, and occasionally a young baboon or bush pig. They are capable of problem solving, tool use, and deceit. Chimpanzees are highly social and live in flexible groups (15–100 or more members) known as communities. In the wild they live about 45 years, in captivity more than 50.