The orangutan, which means "forest man" in Malaysian, is native to Borneo and Sumatra. IN wildlife lives about 40 years. There is a known case when an orangutan in one of the zoos lived to be 58 years old. With a height of 2 meters, the weight of males is on average 120 kg, and females - about 60 kg.

The basis of nutrition is fruit, but the animal is not averse to eating honey, tree bark, mushrooms, insects and even small animals. If there is not enough food, orangutans live alone; when there is a lot of food, they form groups. Often, in search of food, the animal follows birds, which also feed on fruits. To quench their thirst, orangutans do not have to go down to the ground; they drink rainwater accumulated on the leaves. The method of drinking is interesting: the animal dips its forelimb into water, then sucks the moisture out of the fur. Orangutans promote plant reproduction: by eating fruits, they scatter seeds throughout the forest.

Orangutans have a very muscular and strong physique, which allows them to “travel” well through the trees. The coat is long and has a reddish tint. It is absent on the face. The cheeks of males have fatty growths the size of a small plate. Monkeys move on the ground on all fours. They grab branches with their feet; they are as flexible as their hands. Orangutans' arms are twice as long as their legs: a standing monkey's arms hang down to the ankles. The animal moves by swinging and jumping along the branches. The arm span sometimes reaches 2 meters. Strong fingers help them not to fall, with the help of which they tenaciously hold on to the branches. Orangutans use leaves to protect their hands from thorny branches.

A female orangutan can bear offspring at the age of 9 years. Its habitat borders the territory of its mother. The baby is born in a nest that the mother builds high in a tree. The newborn weighs about half a kilo. The little orangutan cries like a human baby. The mother constantly monitors the cleanliness of the cub and carries him everywhere. Until four months, the baby is under the mother’s every minute supervision. Orangutans cannot survive without their mother longer than any other animal. They grow very slowly, until four years They feed on mother's milk. For the first two years, his mother not only feeds him, but also prepares his bed for the night and teaches him to choose foods suitable for eating. From 2 to 5 years old, children can take independent walks, but their mother still looks after them. Jumping through the trees, they insure themselves by holding the hand of their elders. Until the age of 8, animals spend almost all their time alone. They are busy building nests and searching for food. However, they often still visit the mother, who by that time has a new baby.

Males reach maturity at 15 years of age. They usually live alone or in the company of peers. When the time comes to establish their territory, males develop growths on their cheeks and a characteristic throat pouch. Males make hooting sounds to attract females. The call of the male can be heard at a distance of up to a kilometer.

Orangutans are smart animals. They stick twigs into trees and thus catch insects. Hard fruits are broken with stones. Orangutans sometimes steal boats to cross the river.

The number of animals is sharply declining due to the destruction of forests. However, scientists are making a lot of efforts to preserve this animal population. Many reserves have been created where offspring born in zoos are sent. Here, in conditions as close to wild as possible and under human supervision, animals learn to survive.

Surely every person knows the story of King Kong - a huge monkey who was able to destroy half the city. Of course, primates are not capable of reaching such sizes. However, among the closest relatives of man there are real giants.

The largest ape in the world is the gorilla. These unique primates were first discovered in the mid-19th century by a missionary from America who went to explore the tropical forests of Central Africa. The average height of a male gorilla reaches 170 centimeters! There is information that at the beginning of the twentieth century, hunters shot an individual whose height exceeded 230 centimeters; perhaps it was this incident that inspired directors to create films about King Kong.

Gorillas weigh from 120 to 250 kilograms, and the width of their shoulders can reach one meter. This giant is not only large in size, but also extremely strong. True, gorillas have a peaceful character: only a few cases of attacks on humans have been recorded. The gorilla never attacks first; it becomes aggressive only if the need for self-defense arises. In addition, these large monkeys run very quickly on all fours, so they will prefer to hide in the thickets of tropical vegetation rather than engage in open confrontation.

A gorilla can live about five decades. Females give birth to one baby at a time, which remains with the mother for quite a long time: until a brother or sister is born

Gorillas live in small groups consisting of two to three dozen animals. Moreover, in the flock there is always one main male who tirelessly defends his rights to a leadership position. Gorillas fight quite rarely: they prefer to demonstrate their power to competitors by making characteristic blows to the chest with their fists and emitting a loud guttural roar.

Nowadays, the number of gorillas has greatly decreased due to deforestation. tropical forests. Fortunately, gorillas tolerate captivity well enough that they are kept in almost all the world's major zoos. Thanks to this, gorillas are not yet in danger of extinction.

Second place in the ranking of the largest monkeys is rightfully taken by orangutans - the closest relatives of humans, whose height reaches 1.5 meters in males and about one meter in females. Orangutans weigh from 50 to 135 kilograms. The hind limbs of these primates are quite short, and the forelimbs are long, which gives the monkey a rather characteristic appearance.

Orangutans live on the islands of Borneo and Sumatra. They prefer to spend almost their entire lives in the crowns of trees, along whose branches they move, deftly using their long forelimbs.

Orangutans are so adapted to living in trees that they even stopped going down to drink: they are quite satisfied with the water that accumulates on the leaves of the trees or even on their own fur.

Orangutans are the true intellectuals among other great apes. They often use various tools, such as sticks and stones. In addition, studies have proven that the level of mental development of an orangutan can be compared with a three-year-old child: monkeys are quite capable of solving simple problems, adding numbers, remembering colors, etc. By the way, orangutans pass on the knowledge and skills acquired during their life to their descendants.

Individuals in a flock can communicate with each other and make collective decisions

Unfortunately, these amazing monkeys may disappear from the face of the planet, which is associated with illegal deforestation of Sumatran forests and the activities of poachers who catch baby orangutans for sale. As a rule, the mother never gives up the little cub of her own free will, so poachers have to kill the unfortunate females to achieve their goal.

Howler monkeys are considered the largest primates living in South America. Of course, compared to gorillas, howler monkeys are real dwarfs, because their height rarely exceeds 70 centimeters. Howler monkeys weigh about eight kilograms. Primates got their name due to the presence of special vocal sacs, which allow them to produce a loud roar that can be heard at a distance of up to five to six kilometers. Researchers compare the roar of primates to the sounds that could be heard during a battle of all existing animals: howler monkeys can imitate the growl of a leopard, the grunt of a pig, and even a human cry.

The ability to imitate various sounds helps howler monkeys protect their territory: having heard the cries of a relative, the male will not invade his rightful possessions. Thus, monkeys manage to avoid conflicts for resources and for females

This rating would be incomplete without a description of the largest extinct ape - Gigantopithecus. The history of the discovery of these amazing primates is quite interesting. In 1935, German researcher Gustav von Koenigswald purchased monkey teeth from a Chinese shop that were twice as large. more teeth gorillas. The Chinese believed that these teeth belonged to dragons and used them to treat various diseases. However, the paleontologist concluded that the teeth belonged to an extinct monkey whose height reached approximately four meters. This monkey is called Gigantopithecus.

It has been established that Gigantopithecus existed simultaneously with Pithecanthropus. At the same time, huge primates even used primitive tools, which indicates a fairly high intellectual level

Interestingly, according to one exotic hypothesis, Gigantopithecus did not become extinct, but survived in some inaccessible mountainous areas of the planet. Cryptozoologists claim that the Yeti, or snow people, which some tourists observed, are miraculously surviving representatives of the genus Gigantopithecus. However, it was not possible to prove this version: not a single giant ape has yet been caught. Although this option cannot be ruled out, because it is known that the lobe-finned fish, long considered extinct, was discovered by researchers in 1938 off the southern coast of the African continent.

Now you know which monkey is the largest on the planet. Who knows, maybe gorillas or orangutans will be able to develop their intelligence so much that they will take the place now occupied by humans?

Orangutans are one of the world's most famous and popular species of great apes. Scientists consider them, along with gorillas and chimpanzees, to be among the animals closest to humans. Currently, only two species of these red monkeys are known - the Sumatran orangutan and the Bornean orangutan. In this article we will consider in detail only the first of them.

Orangutan or orangutan?

Some people believe that the pronunciation and spelling of the name of this monkey comes down entirely to one single option - “orangutan”. Even Microsoft "skips" this word, while the word "orangutan" is underlined in red. However, this spelling is erroneous.

The fact is that in the language of the population living in Kalimantan, “orangutan” is a debtor, and “orangutan” is a forest person, a forest dweller. That is why preference should be given to the second version of the name of this beast, even despite the fact that some text editors they still “consider” its spelling to be incorrect.

Where does this monkey live?

The Sumatran orangutan, a photo of which you can see in our article, lives throughout the territory of Kalimantan. However, the vast majority of these monkeys are found in northern Sumatra. Their favorite habitats are tropical forests and jungles.

Sumatran orangutan. Description of the species

It is believed that these have their African counterparts - gorillas. This may be true, but the ape-like features of orangutans are much more pronounced than those of gorillas. For example, the forelimbs of the red monkey are long, and the hind limbs are noticeably shorter than those of their African relatives. The hands and feet with long curved fingers in orangutans play the role of peculiar hooks.

With the help of its crooked fingers, the Sumatran orangutan easily clings to branches and picks tasty fruits, but we will talk about this a little later. Unfortunately, his limbs are not adapted for the most complex actions. As for the size of these monkeys, adult male orangutans are inferior in size to gorillas, and they weigh less. The Sumatran orangutan, whose weight does not exceed 135 kilograms, can reach a height of only 130 centimeters.

However, if you do not compare the size of orangutans with the size of gorillas, then these are quite impressive apes: their arms span is 2.5 meters, and their body is massive and dense, completely overgrown with red hair hanging in clumps. The Sumatran orangutan, whose head has a round face with swollen cheeks, turning into a funny “beard,” also makes peculiar sounds, which we will learn about later.

Why do Sumatran orangutans grunt?

Researchers observing the behavior and lifestyle of Sumatran orangutans noticed that these monkeys sigh constantly and heavily. Once, the famous zoologist and professor Nikolai Nikolaevich Drozdov, while studying these animals in one of his television programs, remarked: “He groans like an old man in pain. But he is not an old man, and he is not in pain. He is an orangutan."

It is curious that the throat sac of these animals swells like a ball, emitting squelching sounds, gradually turning into deep throaty moaning. These sounds cannot be confused with any others. You can hear them even a whole kilometer away!

Orangutan lifestyle

The average lifespan of these animals is about 30 years, the maximum is 60 years. These red-haired “old men” prefer to live alone. If you ever happen to meet a small group of Sumatran orangutans, then know that this is not a clan of monkeys, but just a female with her offspring. By the way, females, when meeting each other, try to disperse as quickly as possible, pretending that they do not see each other.

As for males, the situation here is, of course, more complicated. Each adult Sumatran orangutan has its own territory, in which several females live at once. The fact is that the males of these monkeys are polygamous creatures and prefer to have a whole harem at their disposal. The owner of the territory warns strangers who wander into his domain with loud shouts. If the alien is not going to leave, then a showdown begins.

This happens in a very unusual way. Both orangutans, as if on command, rush to the nearest trees and frantically begin to shake them. It resembles a real circus: trees shake, leaves fall from them, heart-rending screams are heard throughout the area. This show goes on for quite some time long time until one of the opponents loses their nerve. Usually the losing male Sumatran orangutan vomits and gets pretty tired.

The main part of the life of red monkeys is spent exclusively in trees. They also sleep high above the ground, having previously arranged a comfortable bed for themselves. It is worth noting that the Sumatran orangutan is a rather peaceful animal. However, as we already know, this principle does not apply to their relatives: fights for territory between them occur on a constant basis.

What do these monkeys eat?

In principle, the Sumatran orangutan (photos of these monkeys usually evoke a lot of impressions) is a vegetarian. So they happily feast on mangoes, plums, bananas, and figs.

Thanks to their incredible strength and other physical characteristics, these monkeys quite deftly climb the tallest tropical trees of the islands for their favorite delicacy - mangoes. If, for example, the upper branches of the trees are thin, an impressively sized red ape calmly sits in the middle of the crown, bending the branches towards itself. Unfortunately, this is detrimental to the trees themselves: the branches break and dry out.

Orangutans that live on the island gain weight quite quickly. And all because summer here is the most favorable time for red-haired “forest dwellers”. The abundance of variety allows monkeys not only to gain weight quickly, but also to store fat for the rainy season, when they will have to eat exclusively bark and leaves.

Orangutan population

As mentioned above, in nature there are two species of these monkeys: the Bornean and Sumatran orangutan. The number of these animals over the past 75 years, unfortunately, has decreased by 4 times. The main factors negatively affecting their population are:

• constant environmental pollution;
• illegal catching of young animals and their sale.

Moreover, animals are highly dependent on the state of the tropics in which they live. This is why widespread deforestation of the jungle, which is leading to the death of orangutans, should be stopped. Currently, there are only about 5 thousand of these monkeys left. If measures to protect them are not taken in time, they may disappear from the face of the Earth forever.

Class Mammals (Mammalia)
Subclass Trechnotheria
Infraclass Higher Beasts (Eutheria)
Superorder Archons (Archonta)
Grand detachment Euarchonta
Primates Squad
Suborder Euprimates
Infraorder Dry-nosed monkeys (Haplorhini)
Parvotorder Anthropoidea
Narrow-nosed monkeys (Catarrhini)
Superfamily Hominoidea
Family Hominidae
Subfamily Ponginae
Tribe Pongini
Genus Orangutans ( Pongo)

Orangutans, or orangs ( Pongo Lacépède, 1799) is a genus of large arboreal hominids (Hominidae) from South-East Asia, where they have been known since the Pleistocene. 3 fossils and 2 modern looking which are now endangered.

Appearance of a young male Pongo abelii.

Etymology and history of study

The name “orang-utan” is of Malay origin and means “man of the forest” (it is noteworthy that local farmers - the Bataks - call this not only monkeys, but also primitive tribes of forest gatherers, for example, Kubu). The name “orangutan” sometimes used is erroneous, as it means “debtor man.” Since ancient times, local residents have hunted orangutans, sometimes tamed them and kept them as pets. The remarkable intelligence of these monkeys has long been noticed by the population of the region. Thus, according to one of the beliefs, orangutans can speak well, but do not do this in front of people, so that they do not force them to work.

Apparently, the word “orangutan” was first used in scientific publications in 1641 by the Dutchman Nicholas Tulp; however, he designated it as a chimpanzee from Angola. Considering that Europeans first arrived in Kalimantan a hundred years earlier, Malay tales about the “forest people” were probably already widespread by this time. Another Dutchman, Jacob Bontius, former doctor in Java, he soon correctly used the word “orangutan” when describing an animal from the islands of Sumatra and Kalimantan (his description was included in Buffon’s “Natural History”). Still, until the end XVIII century orangutans often continued to be called all anthropoids indiscriminately.

Antique image of an orangutan (1876).

Modern generic name Pongo dates back to the English sailor Andrew Battelle, who in the 16th century designated the anthropoid African primate (most likely a gorilla). Relative order in the taxonomy of anthropoids was established only in the 19th century. Initially, only one species was identified - Pongo pygmaeus, however, at the beginning of the 21st century, based on morphological, behavioral and genetic differences, the independence of the second species was confirmed - Pongo abelii. Since the 19th century, hundreds of scientific papers have appeared on orangutans with all sorts of anatomical and physiological details - and often with speculative constructions based on these characteristics, since none of those authors apparently observed these primates in the wild.

Barbara Harrison first began researching orangutans in the wild in the mid-twentieth century. Another outstanding researcher who has continued to work in this field almost to this day is Birutė Galdikas. In addition to this, along with others great apes, orangutans have been subjected to many laboratory studies to study their intelligence and communication abilities. In contrast to being quite rare in nature, in captivity they have recorded numerous cases of using tools. The monkeys also demonstrated the ability to solve complex tasks, such as opening a locked box. As part of the study of communication, orangutans were taught sign language and graphic symbols. In early 2011, a group of researchers announced that they had sequenced the genome of these primates.

old male Pongo pygmaeus.

Morphology

Orangutans are large apes with pronounced sexual dimorphism; males are much larger than females. The average body length of adult males is 95-100 cm, females - 75-80 cm; height in a straightened position is 120-140 (up to 158) cm in males and 100-120 (up to 127) cm in females. The body weight of adult males is 50-90 kg, but in captivity they become very fat and can reach 190, and according to some reports, even 250 kg. Huge size and unique appearance serve the male to intimidate competitors if they attempt to encroach on his territory and powers. Females are approximately half the weight and weigh about 30-50 kg. Orangutans from Kalimantan and Sumatra are approximately equal in size and weight, but the maximum values ​​were recorded among the Sumatran inhabitants.

Portraits of an adult male and female Pongo pygmaeus.

The build of orangutans is massive and rather awkward, they have highly developed muscles, and usually have a large round belly. These animals are perfectly adapted to an arboreal lifestyle. Their powerful forelimbs are greatly elongated, reaching almost to the ankles when the body is straightened, and their span in large individuals can reach 2.25 m. The ulna and radius are longer than the humerus. The hands are elongated and wide, the first finger is poorly developed and almost incapable of manipulation, the remaining fingers are long and strong. When moving through trees, the four fingers of the hand grasp the branch like a powerful hook. The hind limbs are 30% shorter than the forelimbs.

Due to the great mobility of the wrist and shoulder joints, when climbing branches, the orangutan can twist at a variety of angles. The hip joint is also almost universal. The monkey is able to stretch its leg down, back, forward, to the side at a right angle and almost vertically upward. Due to life in the trees, the first toe is vestigial and often lacks a nail, but can rotate and be opposed to the remaining toes; the other toes are well developed. The foot is kept in a bent state and is capable of grasping, not inferior in tenacity to the hand.

Skeletons of males Pongo abelii.

The hair is quite sparse, but shaggy and long. In adults, on the shoulders and upper parts It is so large that it hangs in shaggy hairs more than 40 cm long. The fur is hard, reddish-red, and darkens a little with age. Coat color varies from bright orange in young animals to brown or dark chocolate in some adults.

The lungs are not divided into lobes. In front of the powerful neck there is an unpaired laryngeal sac with many branches, which serves to amplify the voice. In males, the capacity of the sac reaches several liters; in females it is less developed. There are usually no ischial calluses; they occur only occasionally and are small in size. Orangutans have blood types A, B and AB (no type O) and other human blood components. They have a diploid set of 48 chromosomes.

Left hand and foot Pongo abelii.

The head is large and rounded. The front part is wide, slightly pushed forward and has a spherical shape. The skull is quite high. Males have highly developed sagittal and lambdoid crests. The forehead, unlike most anthropoids, is high and convex; the brow ridges are moderately developed. The eyes are small, close-set. The facial profile is concave, the jaws protrude strongly forward. The brain is relatively large, reaching 300-500 square meters. cm in volume and similar to a human.

The face is bare, wide; ears are small; The lips can stretch out greatly, especially the lower one. The complexion is grey, brownish or almost black, slightly pinkish in young animals. In adult males, elastic, slightly hairy growths develop on the sides of the head in the form of semicircular ridges up to 10 cm wide and up to 20 cm long, formed by adipose and connective tissue. The ridges converge on the forehead at the top, and merge with the resonator bag at the bottom. From the outside, it seems as if the monkey's face is edged with thick folded skin. The ridges continue to grow after puberty and largest size reach in old animals. With age, males also develop a yellowish beard and mustache, growing no longer in the middle above the high upper lip, but on its sides. Adult females also have a beard, but it is not as developed.

Scull Pongo pygmaeus, front and bottom views.

The jaw apparatus is quite massive, the teeth are large. Like other Old World monkeys, the dental formula is I2/2 C1/1 Pm2/2 M3/3 = 32. The enlarged incisors are spade-shaped, especially the large first pair. The fangs of males are much larger than those of females. Molars are large and flat, have a ribbed surface and hard enamel. The chewing surface of the cheek teeth is covered with a complex pattern of fine grooves and wrinkles. The jaws and teeth of orangutans cope with both soft and hard food with equal success and are an excellent device for picking fruits, branches with termite nests, stripping bark from trees, grinding hard seeds, cracking shells and nuts.

Midsection of an orangutan's head.

Habitat

Orangutans used to live throughout Southeast Asia, but today they survive only in some areas of Sumatra and Kalimantan. They usually inhabit primary and secondary rain forests in swamps, plains and hills at an altitude of 200-400 m above sea level, but sometimes rise into the mountains to a height of up to 1500 m.

Rainfall in Sumatra averages about 3,000 mm per year, with wet seasons lasting from March to June and September to December. The average annual temperature is 29.2 °C, but in different months it ranges from 17 °C to 34.2 °C. Humidity reaches around 100% throughout the year. Kalimantan is even hotter and more humid. There is an average of 4,300 mm of precipitation per year. The wet season lasts from December to May, September is also rainy, and June to August is quite dry. Air temperatures range from 18°C ​​to 37.5°C.

Distribution area of ​​orangutans.

Orangutans are rather phlegmatic animals that grow slowly, reproduce little and live a long time. Their life, quite calm and lazy, is a consequence of existence in an environment where mortality is low and periods of starvation are not big problem. In Sumatra, a monkey can become a victim of a tiger ( Panthera tigris sumatrae). The much smaller clouded leopard ( Neofelis nebulosa), living in Kalimantan and Sumatra, poses a danger mainly to females and cubs. Sometimes these monkeys are attacked by crocodiles and feral dogs.

Movement

Orangutans lead a purely arboreal lifestyle, found at all levels of tall trees. Among modern arboreal mammals they are the largest. These monkeys easily swing on branches (brachiate), climb and walk on them, and in most cases they do this carefully and without haste. They never jump like gibbons because they are too heavy to do so. However, in the upper part of the forest, orangutans are able to move at a speed no less than that with which a person runs on the ground. Usually, when moving, the body is in an upright position, the lower limbs feel for branches, but step on them not with the entire sole, but only with bent fingers, while the upper limbs alternately intercept the branches, first testing them for strength.

Juvenile Pongo abelii on the tree.

Sometimes monkeys swing the tree they are sitting on from side to side until they can grab onto a nearby tree with at least two limbs. This is achieved due to their tenacity and ability to move freely in different directions. Both the hands and feet of orangutans are perfectly adapted for grasping. Monkeys can climb high into tree crowns. Incredible strength and agility allows animals to reach food that would otherwise be inaccessible.

As a rule, monkeys hang prostrate on trees, holding onto branches with those limbs that are more comfortable for them, and with their free limbs they obtain food for themselves, mainly fruits. If large males, because of their heavy weight They cannot climb the thin branches on which fruits grow; they simply sit in the middle of the crown and begin to break or bend the branches towards themselves. In this way, they manage to quickly clear the tree of fruits, while maiming and breaking many branches.

Pongo pygmaeus moves on the ground.

Females and cubs rarely come down from the trees, but overweight males can sometimes be seen on the ground. As a rule, monkeys go down only to move to a new tree. Here they move slowly on all fours, resting on the dorsal surfaces of the middle phalanges of the fingers of the forelimbs and on the outer edges of the feet; They can also step on hands clenched into fists. Sometimes, when moving faster, the hind limbs are thrown forward between the forelimbs. In Kalimantan, monkeys descending from the trees can be seen more often. This is due to the fact that, unlike Sumatra, there are no tigers. Orangutans cannot swim, but they have sometimes been spotted in the water.

Female Pongo pygmaeus wades into a pond with a cub.

Nutrition

Orangutans can eat a lot and sometimes spend the whole day sitting on a tree with fruits and eating them. It has been established that the diet of these primates includes up to 400 various types plants. From 60 to 90% of everything eaten are fruits - both ripe and unripe, especially those with sweet and fatty pulp (durian, jackfruit, figs, rambutan, lychee, mangosteen, mango, plums, etc.). Most often, monkeys are attracted to durian trees up to 30 m high, with sparse foliage. Durian fruits, which look like spiky footballs, are a favorite food of orangutans. Having picked the fruit, they open it with their teeth and hands. Then, sticking their fingers inside, they extract the white pulp with nuts and eat it.

In some areas, the basis of the diet is the fruits of fig trees, since they are highly productive, quite easy to collect, and they are easily digested. At the same time, orangutans consume even fruits containing strychnine without any difficulty. Strychnos ignatii, the only visible effect of which is perhaps increased salivation. By spreading the seeds of the fruits they eat, these primates contribute to the spread of many plants. There have been cases of orangutans using the plant. Commelina, which has an anti-inflammatory effect.

When there are not enough fruits, orangutans feed on seeds or tear off the bark from trees and vines in order to get to its inner layer - the phloem; it is in such hungry times that good and strong teeth serve them faithfully. In addition, monkeys regularly eat young leaves, shoots and flowers, and sometimes feast on chicks, bird eggs, lizards, honey, insects, snails and other small invertebrates; sometimes they eat soil rich in minerals. In addition to being rich in micro- and macroelements, consumed clay soil can be useful because it absorbs toxins contained in plant foods, and it also helps with intestinal disorders, such as diarrhea.

A male orangutan eats leaves.

There is also information about orangutans eating meat. So, in national park In Indonesia, Gunung Leser, a pair of adult animals, a male and a female, fed on the carcass of a white-handed gibbon for 3 hours, eating it without a trace. Usually, primates are content with moisture obtained from juicy fruits, but if this is not enough, they drink water that accumulates in the recesses of trunks, lick raindrops from fur and trees, suck moss, orchids or their hand, which was previously lowered into the water.

In Indonesia, with a pronounced change of seasons, summer is the happiest time for orangutans. Thanks to the abundance of fruits, monkeys eat a lot and quickly gain weight, storing fat for the future, for the rainy season, when bark and wood will be almost their only means of subsistence. During this unfavorable time, they are forced to go for many days without food at all. Obviously, it is the predisposition of orangutans to overeat when there is a large amount of available food that is the main reason for their obesity in captivity.

Metabolism

It was recently discovered that orangutans have a metabolic rate that is approximately 30% lower than that calculated based on their body weight. It is estimated that the average orangutan consumes between 1,100 and 2,000 calories throughout the day. For comparison: a person who is not burdened with even light physical work, as a rule, burns 500-1000 more calories per day. It is likely that orangutans developed such a low level of metabolism due to their leisurely lifestyle and seasonal minimum of food resources.

Rest

Orangutans are active during the day. Like other large anthropoids, they build nests at night. Having chosen a reliable place, usually in a fork of branches, primates deftly break off large branches around themselves and lay them in different directions until they form a sufficiently reliable platform. The movements of the animals are measured and unhurried; sometimes they take a branch again and rearrange it in a different way. Then the resulting frame is braided with thin twigs and laid out on top with leaves, and they are often placed in an “artistic” order. The resulting litter is compacted. At night, especially in rainy times, orangutans often cover themselves with branches or some large leaves; sometimes another layer of platform is built to provide a secure, waterproof roof. Nests are built in the middle part of a tree at a height of 10-20 m from the ground, where it is less windy.

The female sleeps in the same nest with the calf, holding it to her chest. Other members of the group, as a rule, build separate nests for themselves, sometimes helping each other. They sleep in the same nests during the day; Sometimes new nests are built for daytime rest. Usually the nest is used for one night or several nights in a row if the monkeys stay in the same place for a long time. Sometimes a new nest is built next to the old one. Orangutans sleep supine or on their sides with their legs pressed to their stomachs, holding a branch with one or both hands. It is known that they spend about 60% of their time sleeping. Waking up with the first rays of the sun, they leisurely stretch and scratch themselves, rub their eyes with their fists and look around. Then they leave the nest and go to breakfast. Orangutans also like to spend the hottest afternoon hours dozing in their nests. Thus, the main activity of monkeys occurs in the morning and evening.

Communication

Compared to other great apes, orangutans' vocal abilities are not very diverse. Sometimes they sigh heavily, grunt and squeak. Monkeys express a threat with loud smacking and puffing, while whimpering and crying indicate anger, irritation or pain. A young animal may whine, asking its mother for something.

A male, wanting to mark his territory or attract the attention of females, emits a peculiar loud cry. His vocal exercises begin with a deep, vibrating squelch that gradually turns into a deafening wail. In this case, the monkey’s throat sac inflates like a ball, and large air resonator cavities located under the skin of the chest amplify sounds so much that they can be heard a kilometer away. The performance ends with a bass grunt. As one researcher noted, the orangutan's "song" resembles the sounds of a car when changing gears.

Orangutan communication.

When the patterns of how female orangutans react to a call addressed to them were analyzed, it turned out that what was previously considered simply a “mating cry” in fact serves not just to attract attention, but contains very specific information about the personality and status of a potential mating partner. His chances increase further if a third male intervenes in the conversation, over whom he can demonstrate superiority. The researchers were also able to identify two main patterns of communication between orang males. The first, “preventive” one, is addressed by an adult male to young or weak potential rivals so that they stay away. The second option is an almost instant response of the dominant to the heard call of another male.

It has also been noted that when orangutans make sounds warning of approaching danger, they can significantly change their voice with the help of leaves attached to their mouths. The sounds they make in this way not only signal their relatives about the threat, but also show the potential attacker (leopard, tiger, snake) that he has been discovered. Normal (lip) calls of orangutans are quite high-pitched at about 3500 hertz, the hands lower the frequency to 1800, and the leaves to 900 hertz. Meanwhile, the lower the sound, the greater the likelihood that the animal is large, which means it is better not to mess with it and look for a smaller victim. Perhaps by using the leaves, orangutans are trying to deceive the predator, because they only make alarm calls when they are very frightened.

It has been noticed that in those populations where such deception exists, almost all orangutans use it. of different ages. This could mean that this method Quite effective against attackers. However, since the reaction of predators to “modified” calls has not yet been established, this cannot be said for sure. Still, it is curious that animals that were not accustomed to the presence of humans nearby screamed much more often than those that were already familiar with Homo sapiens. The above facts indicate that orangutans understand what other animals know and what they do not know (i.e., how predators perceive one or another of their calls). One way or another, these monkeys are the only creatures besides humans capable of manipulating sound using improvised means.

In addition, during the course of evolution, orangutans have developed a rich gestural vocabulary, allowing them to communicate with each other quite intensively. The researchers identified 64 different gestures in these primates (28 individuals from three European zoos were studied), and 40 of them were repeated often enough to accurately determine their meaning, which was equally understood by almost all experimental animals. Based on the results obtained, a dictionary was compiled. It contains gestures such as somersaulting, turning back, biting the air, pulling hair, placing objects on the head (the latter means “I want to play” - this is perhaps the most common utterance in the language of orangutans). And to show that it is required to follow it, the monkey hugs the communication partner and easily pulls in the right direction.

It is noteworthy that some of these gestures are similar to human gestures. For example, to give a “stop” signal, the orangutan lightly presses the hand of the “interlocutor”, who, in the first monkey’s opinion, is doing something wrong. Human children who cannot speak often do the same thing. Monkeys can quite persistently repeat a gesture if their counterpart does not respond to it with a certain action, that is, they clearly speak body language, putting a very specific meaning into their deliberate message. Combined with the high frequency of use, all this may indicate the initial stage of the formation of a kind of language. The facial communication of orangutans has not yet been studied enough.

Pongo abelii in the process of communication with a relative.

Intelligence

Among primates living in captivity, orangutans gain greatest number points in intelligence experiments. Without any particular difficulties, they learn to use a rudimentary language system focused on six food objects and in 2 years are able to learn and use about 40 token signs. These monkeys also demonstrate the ability to independently invent and change gestures depending on how well others understand them.

In a number of experiments, orangutans have shown that they are quite capable of accepting the value of money and even buying food for each other, but they do this only if the subsequent sharing of it is of equal value. “If you don’t give me enough, then I won’t share with you, but if you have at least some benefit, then I’m ready to buy your cooperation,” this is roughly how researchers describe the thinking of these primates, weighing costs and benefits from their interactions with their peers.

The great intelligence of orangutans is especially striking when observing them in captivity. Thus, an old male named Marius at the Munich Zoo instituted a special procedure for keeping his cage clean. He began using an old soldier's helmet as a chamber pot. Having sat down on it and done everything necessary, he carefully carried the helmet to the grate and poured the contents through the bars into the drain. This orangutan was generally particularly clean and swept all the rubbish out of the cage. The servants hardly had to clean up after him.

Wild orangutans use their intelligence to create complex patterns to obtain food. Sometimes they invent devices that allow them to reach food supplies that are inaccessible to other jungle inhabitants. In some places in Sumatra, monkeys deliberately adjust twigs to extract seeds from large Nessia fruits, since these seeds are protected by a mass of spiny hairs. The leaves are used as napkins to dry yourself, or as gloves to protect yourself from the thorns on the durian fruit. It is known that the trapping pitcher leaves of insectivorous plants served as a cup for monkeys.

Orangutans also use special tools to extract honey from bee nests or to check tree hollows for the presence of ants or termites, scratch themselves with sticks, brush away annoying insects with branches, and make a kind of umbrella out of leaves to protect them from rain or sun. In captivity, monkeys used sticks to push bait out of the tube and chewed branches, turning them into a sponge, which they used to draw water from a vessel. However, although orangutans can manipulate objects well, they use this ability little, being inferior in this regard to chimpanzees.

Orangutans are excellent imitators; they are able to quickly adopt and copy behavior that they have observed in other relatives or even people. Observations of these primates have shown that they can imitate up to 90% of the body movements they see. When around people, monkeys adopt human habits without much difficulty. In rehabilitation centers, some orangutans copied people by washing things in soap and water. They also reproduce techniques for using tools. One young female even learned to cut wood and hammer nails. The natives of Kalimantan - the Dusuns - still use orangutans as pets, starting to raise them from early childhood and teaching them to perform duties in the house: rocking a cradle with a child, carrying water, uprooting stumps, etc.

In one case in Kalimantan, monkeys saw local fishermen with fishing rods, and then tried to catch fish themselves using tools abandoned by people. One male figured out to use a “pole” left by a man as a spear. He climbed onto the branches hanging over the water and tried to pierce the fish swimming below with a stick. Unfortunately, he was unable to get it this way. But using the same tool, this orangutan successfully fished out floating fruits that had fallen into the river. Another orangutan used found sticks to pull a fish ashore that had become entangled in fishing lines with hooks that people had previously thrown into the water.

Young Pongo pygmaeus tries to hit a fish with a stick.

The predilection for repeating the behavior of others, rather than inventing new models of behavior, leads to the emergence of local traditions among orangutans. Thus, all individuals in a population of tool users have certain labor skills, although not all of them use them often. At the same time, members of another population, separated from the craftsmen by just a river, may not have such abilities, may not use certain tools, or use them for other purposes. In addition, in different areas, orangutans use different methods of nest construction, make different sounds and manage food differently.

According to researchers, learning is as important in the life of orangutans as innate instincts. Through the transfer of skills, new behaviors may well be inherited from generation to generation. However, the measured and mostly solitary lifestyle of these primates is not at all conducive to the development and dissemination of acquired skills. This assumption is consistent with the observation that tool activity is much more widespread not among the Kalimantan orangutans, but among the more socially developed Sumatran orangutans.

Territoriality

Since orangutans are large animals and have a corresponding appetite, their population density is usually low - about one animal per 1-3 square meters. km, but in fertile river valleys and swampy forests, the density can reach up to 7 individuals per 1 sq. km. On a day, orangutans move a distance from 100 m to 3 km, on average - slightly less than 1 km. This distance largely depends on the territorial status of the animal.

According to the strategy of territorial behavior among orangutans, one can distinguish “residents”, “suburban residents” and “wanderers”. “Residents” live within an individual plot with fixed boundaries. Females explore and develop territories with an area of ​​70-900 hectares, sometimes their areas partially overlap. Grown-up daughters usually stay close to their mother's territory, but males can wander for years until they settle down. The areas of “resident” males are much larger - they reach 2500-5000 hectares and often overlap with the areas of several females. Given the current sparseness of the population, individual ranges may be even larger. Making regular forays within his domain, the male searches not only for food, but also for a female capable of mating, and also drives out other males - reproductive competitors.

Most males, however, do not have fixed territories, representing "suburban dwellers" or "wanderers". Suburban dwellers spend only a few weeks or months in one area before moving several kilometers away. Thus, during the year they change their location many times. The following year, these males often return to previously inhabited areas. Although the territory they develop ultimately turns out to be much larger than that of the “residents,” the reproductive advantage of the latter is obvious - they freely mate with females living in the territory of their individual areas. Young sexually mature males, as a rule, are “wanderers”. They are not tied to a specific area and do not stay anywhere for long, constantly being on the move. Growing up, such a male can establish his own territory and become a “resident,” choose the lifestyle of a “suburban resident,” or continue to remain a “wanderer.”

Social relations

Of the living primates, the closest relatives of humans, both anatomically and biochemically, are chimpanzees.

Although many chimpanzee populations live in forests or in patches of forest, shrubland, and steppe vegetation, some populations that occupy the edges of chimpanzee habitat exist in hot, dry, open savannah environments where only isolated small groups occur. trees. Consequently, individual chimpanzee populations live in such natural conditions, in which the oldest African Pliopleistocene hominids lived, such as the Hadar hominid. Apparently, these hominids, like modern chimpanzees and gorillas, were arboreal creatures and led a herd lifestyle.

The same or almost the same close relatives; Humans, like chimpanzees, are inhabitants of the tropical forests of Africa, gorillas. Currently, primatologists distinguish three subspecies of gorilla: the western lowland gorilla (Gorulla gorilla gorilla), which lives in Equatorial Africa(Cameroon, Central African Republic, Congo, Equatorial Guinea, Gabon); the eastern lowland gorilla (G. g. graueri), living in Zaire and Uganda; Eastern mountain gorilla (G. g. beringei), living on the border of Uganda, Zaire and Rwanda.

Another large anthropoid, no longer African, but Asian, the orangutan is much further from humans in anatomical and biochemical indicators than chimpanzees and gorillas. The orangutan is a forest dweller, an arboreal creature that leads a “solitary” lifestyle. He forms paired unions only on a short time for mating. In all these features, the orangutan differs sharply from pre-hominids and the most ancient hominids, which, judging by archaeological data, lived in the forest savannah in groups of several dozen individuals and led, if not completely, then mainly a terrestrial lifestyle.

Therefore, in our opinion, an analysis of the organization and behavior of chimpanzees and gorillas, especially their forested populations, can provide a lot for creating a hypothetical model of the ancestral society of ancient hominids. We agree with those researchers who believe that a highly developed complex social behavior ancient higher primates, the plasticity of their psyche (and in these respects they hardly differed from modern African anthropoids) were important factors in hominization.

In any reconstruction of the early stages of anthroposociogenesis based on primatological data, one must, however, keep in mind the fact that certain aspects of the organization of chimpanzees and gorillas, the nature of intra- and intergroup connections have not yet been sufficiently studied.

According to V. Reynolds, chimpanzees have open communities of 60-80 animals each, divided into several matrifocal, i.e., consisting of mothers with cubs, groups and groups of males living mainly separately from them. This point of view is not shared by most researchers, who believe that chimpanzee communities only give the impression of being open and without a specific structure. In fact, a population occupying a certain area of ​​the forest and numbering 40-50 individuals is a closed association in which male groups move between female ones, but all this is within the boundaries of a herd, all members of which know each other.

The demographic characteristics of the chimpanzee community in Mahale (Tanzania), given by M. Hiraiwa-Hasegawa and co-authors, in comparison with the data of other researchers, allow us to judge the general size of the communities, the sex ratio of adults, the number of adults and calves in free-living populations of these anthropoids. As shown in the summary, community sizes range from 19 to 105 individuals, and the ratio of adult males to females ranges from 1:36 to 1.0:1.0. In certain periods, the number of females in the community can increase significantly, reaching a ratio of 1.0:7.0 and even 1.0:11.0. The number of cubs (not sexually mature individuals), as a rule, rarely significantly exceeds the number of sexually mature members of the community, and often turns out to be smaller. Fluctuations occur within the range of 1.0:0.5-1.4.

The trend toward higher numbers of adult females in groups observed by most researchers in chimpanzees may be the result of a number of reasons. First of all, this is a higher mortality rate of male cubs in the first year of life; pronounced competition between males at the intra- and intergroup levels; influx of alien females from other groups.

Based on their field observations, A. Cortlandt, M. Chance, K. Jolly also argue that the chimpanzee herd is not amorphous or fluid in its structure, but, on the contrary, there are certain types of associations that are quite clearly demarcated from each other. Thus, A. Kortlandt identified two types of such associations among the chimpanzees of the Eastern West he studied - a sexual group and a child group. The first consists of males and females without cubs, the second - of females with cubs and sometimes one or two males. In groups of the first type there are an average of 20 animals, of the second - 15, but the former are much more mobile and cover a larger feeding area than the latter.

Pygmy chimpanzees (Pan paniscus) may be of significant interest for the study of anthroposociogenesis. According to many researchers, dwarf chimpanzees, compared to ordinary chimpanzees, have features of infantilism and primitiveness in their physical structure and are closer to the common ancestor of the genus Pan than any other living anthropoids, therefore, closer to the common ancestor of pongids and hominids. Some authors point out Special attention on the significant similarity of the skeleton between Hadar hominids and pygmy chimpanzees. A number of experts believe that the dwarf chimpanzee (bonobo) can be considered a model of the common ancestor of australopithecines (prehominids), later the most ancient hominids, as well as chimpanzees and gorillas. Morphological similarity may determine similarities in ecology and behavior. In particular, this idea, which we share, is expressed by T. Kano. He thinks that studying the ecology and social groups of pygmy chimpanzees may provide clues to solving the mystery of pongid evolution and reconstructing the ecology and social structure of early hominids. Until recently, much less was known about pygmy chimpanzees than about any other anthropoid species, with the exception of coastal gorillas.

Pygmy chimpanzees live in high-trunk, sparse forests in northern Zaire, as well as in secondary forests in cleared areas. They feed on fruits, leaves, fleshy plant stems, and nuts. According to unverified data, they also fish and collect some underground mushrooms, in search of which they dig holes up to 30-40 cm deep and up to 50 cm in diameter. Both in terms of the location of their food sources and their roosting location, pygmy chimpanzees are more terrestrial than arboreal creatures. In any case, they spend no less time on the ground than their larger relatives.

Pygmy chimpanzees live in communities of usually 50 to 120 individuals - females, males, cubs and adolescents. Groups with many females and several males have also been observed.

Comparative materials obtained in natural environment habitat for two closely related species - the common and pygmy chimpanzees. Both species share a similar feature of social organization that is unique to primates, often forming temporary groups (parties) within permanent communities. General features of social structure and types of groupings of these types

Despite their significant proximity, bonobos and common chimpanzees differ from each other in a number of ways. First of all, these are living conditions: while chimpanzees are found not only in tropical rainforests, but also in mosaic forest savannas, even dry savannas, then bonobos are residents of exclusively humid tropical forests. If in last years While more and more information is being received about cases of chimpanzees using tools, similar activities have not yet been recorded in bonobos. These two types differ in the details of the social structure and the nature of social relationships between members of the community.

In bonobo communities, unlike chimpanzees, there is a pronounced division into matrifocal units, including mothers with offspring, including sexually mature sons. Groups of only males, single males and females, females with cubs are much less common than in the common chimpanzee. As noted by T. Nishida and M. Hiraiwa-Hasegawa, matrilocal units are very stable and represent the most typical division within a bonobo community. There is a clear tendency among pygmy chimpanzees to form groups of equal numbers of females and males. A higher level of sociability compared to chimpanzees is characteristic of bonobo females. This is manifested primarily in the preferential sharing of food, even with unrelated females, and a higher frequency of grooming. A special element of behavior has been noted - genital friction in bonobo females, which plays a significant role in reducing tension in relations between female representatives, and has no analogue in the behavior of the common chimpanzee.

Certain information has now been obtained regarding intergroup relationships among bonobos. Although contacts between members of different communities are often agonistic in bonobos, as in chimpanzees, communities nevertheless avoid direct conflicts with each other. The above-mentioned features of the social organization and ecology of the bonobo, as well as the features of its morphology in comparison with ordinary chimpanzees, were the reason why some researchers began to talk about the special significance of studying pygmy chimpanzees for reconstructing the ecology and behavior of prehominids and ancient hominids. They point out that the common ancestor of anthropoids and hominids was a forest dweller, judging by paleoecological studies. Both the long-extinct Australopithecines and modern pygmy chimpanzees show a combination of arboreal and terrestrial bipedal creature features in their morphology. According to R. Susman and J. Stern, the groups of ancient hominids were more likely to resemble compact and stable groups of pygmy chimpanzees, rather than the more loosely structured communities of ordinary chimpanzees. The social formations of the most ancient hominids were characterized by low intragroup aggressiveness, cooperation between males, and stable connections between females, which were also typical for groups of pygmy chimpanzees.

Less studied than the organization of chimpanzees is the organization of gorillas. The main studies in nature were done on the mountain gorilla. It is believed, however, that the subspecies practically do not differ from each other in the social structure of the groups. Mountain gorillas live in herds, including adult males, females and young.

About 40% of gorilla groups include more than one silverback male, and therefore it is hardly appropriate to talk about a harem organization of social systems in this species.

On average there are 15-20 animals in the herd. One of the older males (with a silvery back) is the leader of the herd: he directs its movement, protects it, and stops intra-herd clashes. Most animals group around him. The young follow him more and stay closer to him than to their mothers. There may be one or several silverback males (over 13 years old) in a herd. In the latter case, only one of them is the leader, and the rest occupy a peripheral position. But neither they nor the younger, although adult, black-backed males (from 8 to 13 years old) are excluded from mating. Therefore, a herd of gorillas can hardly be called a harem. Rather, it can be defined as a multi-male herd. However, only the leader of the herd mates with all the females, so if not all, then probably most of the black-backed males are descendants of the leader of the herd. A new herd usually begins as a harem when a lone silverback male leads one or more females from a herd, or they themselves leave the herd and join the lone male.

In a growing herd, its leader maintains long-term and strong relationships with several older females. Therefore, we can consider that such a harem-like association constitutes the core of the herd.

A feature of gorilla herds compared to chimpanzee communities (at least forest ones) is the greater stability of their composition and a clearer structure. Therefore, cubs and young animals form long-term associations with their parents, siblings, just one-year-olds and other members of the herd. The presence of these associations leads to rapidly progressing independence of cubs, especially males, after reaching the age of two. In herds where the calf does not have siblings or yearlings, it stays with its mother longer. There are known cases when, after the death of the mother, the father, the leader of the herd, began to take care of the cub (taking it to his nest at night, etc.).

Increasing independence does not lead to a severance of ties with parents. They are preserved not only with the mother, but, apparently, with the father, even in adult animals. This is facilitated by the significant external resemblance of the offspring to their fathers. Not a single case has been recorded in which a father killed one of his cubs. At the same time, the killing of other people's cubs (from other herds) by silverback males is a common occurrence.

The greater stability of gorilla herds compared to ordinary chimpanzees does not exclude the animals from moving to another herd. Mostly adult females who have not yet given birth migrate. Over 900 hours of observations, A. Harcourt recorded up to seven transitions from herd to herd or to a single male in some females. The scientist observed only voluntary transitions of females and doubts that they could be different. In contrast to his opinion, D. Fossey writes about the capture or “abduction” of females by lonely males.

Males never move to another herd. If they leave the herd, they become lonely for a longer or shorter period. Then the male is joined by a female, who has also left the herd, and a a new group. In both chimpanzees and gorillas, the movement of males and females from one herd to another, or the mating of individuals from different herds at the boundaries of their territories, serves as one mechanism for preventing inbreeding. They lead to the exchange of genetic material and to the spread of “protocultural traditions” that arose in one of them in many herds.

Inbreeding is limited not only by the departure of males or females from the natal herd, the mating of members of different herds on the borders of their territories, but also by long-term family ties with siblings and the mother, and, according to some data, also with the father.

As for orangutans, as already noted, their social structure differs from the social structure of other anthropoids. In both subspecies - Bornean (Pongo pygmaeus pyguraeus) and Sumatran (P. r. abelei) the main social link is formed by adult females with one or two cubs. Males lead a solitary lifestyle and have certain territory. Males' home ranges can overlap: they defend the territory from individuals of their own sex. A male's territory may contain several areas of females. In turn, females' territories may overlap, and they, like males, are intolerant of the presence of other adult females. Nowadays, the social organization of orangutans is sometimes defined as a "dispersed harem", or single-male group, since one male typically interacts with several females.

Such a social structure is a manifestation of behavioral specialization and most likely arose in the recent past. Orangutans have retained the ability to maintain constant integrating social contacts between representatives of different sex and age groups. The fact that the ancestors of orangutans led a herd lifestyle is evidenced, from our point of view, by data on the behavior of a group of orangutans in captivity, on an artificial island. Orangutans discover developed abilities to a variety of social contacts with each other in play, grooming, friendly interactions, spatial proximity. At present, it remains unclear whether a female mates during a single estrus period with one or more males, because a female's home range often overlaps with the home ranges of several males.

At the same time, it has been proven that mature males play the main reproductive role in orangutan communities. They are the ones who become involved in long-term “marital” relationships with frequent and intense sexual interactions. Females have a clear preference for males with pronounced secondary sexual characteristics and do not show interest in young individuals. The latter circumstance (selectivity of females) explains the pronounced sexual dimorphism in representatives of this species. The assumption that secondary sexual characteristics develop as a result of severe intermale competition also has real grounds, since it is now obvious that in male orangutans a high level of agonistic behavior and high rank precede the achievement of high reproductive success.

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