How many toes does a monkey have? The human hand turned out to be more primitive than the chimpanzee hand. Yellow-cheeked crested gibbon
home Monkeys are considered primates. In addition to the usual ones, there are, for example, semi-monkeys. These include lemurs, tupayas, and short-heeled lemurs. Among ordinary monkeys
they resemble tarsiers. They separated in the Middle Eocene.
This is one of the eras of the Paleogene period, which began 56 million years ago. Two more orders of monkeys emerged in the late Eocene, about 33 million years ago. We are talking about narrow- and broad-nosed primates.
Tarsier monkeys Tarsiers - species of small monkeys
. They are common in southeast Asia. Primates of the genus have short forepaws, and the heel region on all limbs is elongated. In addition, the tarsier's brain is devoid of convolutions. In other monkeys they are developed.
Sirichta
brown or greyish. The fur of the animals is soft, like silk. Tarsiers take care of their fur coat by combing it with the claws of their second and third toes. Other claws are deprived.
Bankan tarsier
Lives in the south of the island of Sumatra. The bank tarsier is also found in Borneo, in the rain forests of Indonesia. The animal also has large and round eyes. Their irises are brownish. The diameter of each eye is 1.6 centimeters. If you weigh the visual organs of a Bankan tarsier, their mass will exceed the weight of the monkey's brain.
The Bankan tarsier has larger and more rounded ears than the Philippine tarsier. They are hairless. The rest of the body is covered with golden brown hairs.
Tarsier ghost Included in rare species monkeys
, lives on the islands of Greater Sangihi and Sulawesi. In addition to the ears, the primate has a bare tail. It is covered with scales, like a rat's. There is a woolen brush at the end of the tail. Like other tarsiers, the ghost acquired long and thin fingers. With them the primate clasps the branches of the trees on which it conducts most
life. Among the foliage, monkeys look for insects and lizards. Some tarsiers even attack birds.
Broad-nosed monkeys
Broad-nosed monkeys are divided into 3 subfamilies. These are capuchinoides, callimicos and clawedes. The latter have a second name - marmosets.
Capuchin monkeys
Otherwise called cebids. All monkeys of the family live in the New World and have a prehensile tail. It seems to replace the fifth limb for primates. Therefore, the animals of the group are also called tenacious-tailed.
Crybaby
It lives in the north of South Africa, in particular in Brazil, Rio Negro and Guiana. Crybaby enters monkey species, listed in the International Red. The name of primates is associated with the drawn-out sounds they make.
As for the name of the clan, Western European monks who wore hoods were called Capuchins. The Italians called the cassock with it “capucio”. Seeing monkeys with light faces and a dark “hood” in the New World, Europeans remembered the monks.
Crybaby is a small monkey up to 39 centimeters long. The animal's tail is 10 centimeters longer. The maximum weight of a primate is 4.5 kilograms. Females are rarely larger than 3 kilos. Females also have shorter fangs.
Favi
Otherwise called brown. Primates of the species inhabit mountainous regions South America, in particular the Andes. Mustard-brown, brown or black individuals are found in different areas.
The body length of the favi does not exceed 35 centimeters, the tail is almost 2 times longer. Males are larger than females, gaining almost 5 kilograms of mass. Occasionally there are individuals weighing 6.8 kilos.
White-breasted Capuchin
The second name is common capuchin. Like the previous ones, it lives on the lands of South America. The white patch on the primate's chest extends to the shoulders. The muzzle, as befits capuchins, is also light. The “hood” and “mantle” are brown-black.
The white-breasted capuchin's "hood" rarely extends over the monkey's forehead. The degree to which the dark fur is raised depends on the sex and age of the primate. Typically, the older the capuchin, the higher his hood is raised. Females “raise” it while still young.
Saki monk
In other capuchins, the length of the coat is uniform throughout the body. The Saki monk has longer hairs on his shoulders and head. Looking at the primates themselves and their photo, species of monkeys you begin to distinguish. Thus, the saki’s “hood” hangs over the forehead and covers the ears. The fur on the capuchin's face hardly contrasts in color with the headdress.
The Saki monk gives the impression of a melancholy animal. This is due to the downturned corners of the monkey's mouth. She looks sad and thoughtful.
There are 8 species of capuchins in total. In the New World, these are the smartest and most easily trained primates. They often feed on tropical fruits, occasionally chewing rhizomes, branches, and catching insects.
Marmoset monkeys
Monkeys of the family are miniature and have claw-shaped nails. The structure of the feet is close to that of tarsiers. Therefore, species of the genus are considered transitional. Marmosets belong to the higher primates, but among them they are the most primitive.
Wistity
The second name is ordinary. The length of the animal does not exceed 35 centimeters. Females are about 10 centimeters smaller. Upon reaching maturity, primates acquire long tufts of fur near their ears. The decoration is white, the center of the muzzle is brown, and its perimeter is black.
Marmosets have elongated claws on their big toes. Primates use them to grab branches, jumping from one to another.
Pygmy marmoset
It does not exceed 15 centimeters in length. A plus is the 20-centimeter tail. The primate weighs 100-150 grams. Externally, the marmoset appears larger because it is covered with long and thick fur of a brown-golden color. The red hue and mane of hair make the monkey look like a pocket lion. This is an alternative name for the primate.
The pygmy marmoset is found in the tropics of Bolivia, Colombia, Ecuador and Peru. With sharp incisors, primates gnaw the bark of trees, releasing their juices. This is what the monkeys eat.
Black tamarin
It does not descend below 900 meters above sea level. In mountain forests, black tamarins have a twin in 78% of cases. This is how monkeys are born. Fraternal children are born only in 22% of cases.
From the name of the primate it is clear that it is dark. The length of the monkey does not exceed 23 centimeters, and weighs about 400 grams.
Crested tamarin
Otherwise called pinche monkey. On the head of the primate there is an erokeus-like crest of white, long hair. It grows from the forehead to the neck. During times of unrest, the crest stands on end. In a good-natured mood, the tamarin is smoothed.
The crested tamarin's muzzle is bare right down to the area behind the ears. The rest of the 20cm long primate is covered in long hair. It is white on the chest and front legs. The fur on the back, sides, hind legs and tail is reddish-brown.
Piebald tamarin
A rare species, lives in the tropics of Jurasia. Outwardly, the piebald tamarin is similar to the crested tamarin, but does not have the same crest. The animal has a completely bare head. The ears appear large against this background. The angular, square shape of the head is also emphasized.
Behind it, on the chest and front legs, there is long white hair. back, yuoka, hind legs and the tamarin's tail are reddish-brown.
The piebald tamarin is slightly larger than the crested tamarin, weighs about half a kilogram, and reaches a length of 28 centimeters.
All marmosets live 10-15 years. Their size and peaceful disposition make it possible to keep representatives of the genus at home.
Callimico monkeys
They were recently allocated to a separate family; previously they were classified as marmosets. DNA tests showed that Callimiko is a transitional link. There is a lot from the capuchins. Genus presented the only kind.
Marmoset
Included in the little-known, rare species of monkeys. Their names and features are only rarely described in popular science articles. The structure of the teeth and, in general, the skull of the marmoset is similar to that of the capuchin. The face looks like a tamarin's face. The structure of the paws is also marmoset.
The marmoset has thick, dark fur. On the head it is elongated, forming something like a cap. Seeing her in captivity is good luck. Marmosets are dying outside natural environment, do not give birth. As a rule, out of 20 individuals in the best zoos in the world, 5-7 survive. At home, marmosets live even less often.
Narrow-nosed monkeys
Among the narrow-nosed there are monkey species of india, Africa, Vietnam, Thailand. Representatives of the genus do not live. Therefore, narrow-nosed primates are commonly called Old World monkeys. These include 7 families.
Monkeys
The family includes small and medium-sized primates, with forelimbs and hindlimbs of approximately equal length. The first fingers of the hands and feet of apes are opposed to the remaining fingers, like those of humans.
Representatives of the family also have ischial calluses. These are hairless, worn-out areas of skin under the tail. The faces of the ape-like creatures are also bare. The rest of the body is covered with fur.
Hussar
Lives south of the Sahara. This is the limit of the marmoset's range. On the eastern borders of the Hussars' dry, grassy territories, their noses are white. U Western representatives kind of noses are black. Hence the division of hussars into 2 subspecies. Both are included in species of red monkeys, because they are colored orange-scarlet.
Hussars have a slender, long-legged body. The muzzle is also elongated. When the monkey grins, powerful, sharp fangs are visible. A long tail primate is equal to the length of its body. The weight of the animal reaches 12.5 kilograms.
Green monkey
Representatives of the species are common in the west. From there monkeys were brought to the West Indies and Caribbean islands. Here primates blend into the greenery tropical forests, having fur with a swamp tint. It is distinct on the back, crown, and tail.
Like other monkeys, green monkeys have cheek pouches. They resemble those of hamsters. Macaques carry food supplies in their cheek pouches.
Cynomolgus macaque
Otherwise called a crabeater. The name is associated with the macaque's favorite food. His fur, like that of the green monkey, has a grassy tint. Expressive brown eyes stand out against this background.
The length of the Javan macaque reaches 65 centimeters. The monkey weighs about 4 kilograms. Females of the species are approximately 20% smaller than males.
Japanese macaque
Lives on the island of Yakushima. There is a harsh climate, but there are hot ones, thermal springs. The snow melts next to them and primates live. They bask in hot waters. The leaders of the packs have the first right to them. The lower “links” of the hierarchy are freezing on the shore.
Among the Japanese, the largest is the others. However, impressions are deceiving. If you cut off the thick, long fur of a steel-gray tone, the primate will be of medium size.
Reproduction of all monkeys is associated with sexual skin. It is located in the area of the ischial callus and swells and turns red during ovulation. For males, this is a signal to mate.
Gibbons
They are distinguished by elongated forelimbs, bare palms, feet, ears and face. On the other body, the fur, on the contrary, is thick and long. Like macaques, there are ischial calluses, but less pronounced. But gibbons do not have a tail.
Silver gibbon
It is endemic to the island of Java and is not found outside its borders. The animal is named after the color of its fur. She is grey-silver. The bare skin on the face, hands and feet is black.
Silver is medium in size, does not exceed 64 centimeters in length. Females often stretch only 45. The weight of the primate is 5-8 kilograms.
Yellow-cheeked crested gibbon
You cannot tell from the females of the species that they are yellow-cheeked. More precisely, females are completely orange. On black males, golden cheeks are striking. It is interesting that representatives of the species are born light, then darken together. But during puberty, females return to basics, so to speak.
Yellow-cheeked crested gibbons live in the lands of Cambodia, Vietnam, and Laos. Primates live there in families. This is a feature of all gibbons. They form monogamous couples and live together with children.
Eastern hoolock
The middle name is the singing monkey. It lives in India, China, and Bangladesh. The males of the species have stripes of white fur above their eyes. On a black background they look like gray eyebrows.
Average weight a monkey is equal to 8 kilograms. The primate reaches 80 centimeters in length. There is also a western hoolock. He has no eyebrows and is a little larger, weighing about 9 kilos.
Siamang compound-toed
IN great monkey species not included, but is the largest among gibbons, gaining 13 kilograms of mass. The primate is covered with long, shaggy black hair. It fades to gray near the monkey's mouth and chin.
There is a throat pouch on the siamang's neck. With its help, primates of the species amplify sound. Gibbons have a habit of calling each other between families. This is why monkeys develop their voice.
Pygmy gibbon
It cannot be heavier than 6 kilograms. Males and females are similar in size and color. At all ages, monkeys of the species are black.
Once on the ground, dwarf gibbons move with their arms behind their backs. Otherwise, long limbs drag along the ground. Sometimes primates raise their arms up, using them as balancers.
All gibbons move through trees by alternating their forelimbs. The manner is called brachiation.
Orangutans
Always massive. Male orangutans are larger than females, with hooked fingers, fatty growths on the cheeks, and a small guttural pouch, like gibbons.
Sumatran orangutan
Belongs to the red monkeys, has a fiery coat color. Representatives of the species are found on the islands of Sumatra and Kalimantan.
Sumatran is included in species of apes. In the language of the inhabitants of the island of Sumatra, the primate’s name means “forest man.” Therefore, it is incorrect to write "orangutaeng". The letter "b" at the end changes the meaning of the word. In the Sumatran language, this is already a “debtor”, and not a forest person.
Bornean orangutan
It can weigh up to 180 kilos with a maximum height of 140 centimeters. Monkeys of the species are like sumo wrestlers, covered with fat. The Bornean orangutan also owes its large weight to its short legs against the backdrop of its large body. Lower limbs By the way, the monkey has curves.
The arms of the Bornean orangutan, as well as others, hang below the knees. But the fatty cheeks of representatives of the species are especially fleshy, significantly expanding the face.
Kalimantan orangutan
It is endemic to Kalimantan. The monkey is slightly taller than the Bornean orangutan, but weighs 2 times less. The fur of primates is brownish-red. Bornean individuals have a distinctly fiery fur coat.
Among monkeys, orangutans of Kalimantan are long-lived. The age of some ends in the 7th decade.
All orangutans have a concave skull at the front. The general outlines of the head are elongated. All orangutans also have a powerful lower jaw and large teeth. The chewing surface is clearly raised, as if wrinkled.
Gorillas
Like orangutans, they are hominids. Previously, scientists used this name only for humans and their ape-like ancestors. However, gorillas, orangutans and chimpanzees have relations with people common ancestor. Therefore, the classification was revised.
Coast gorilla
Lives in equatorial Africa. The primate is approximately 170 centimeters tall and weighs up to 170 kilograms, but often around 100.
Males of the species have a silver stripe running down their back. Females are completely black. Representatives of both sexes have a characteristic red marking on the forehead.
Lowland gorilla
Found in Cameroon, Central African Republic and Congo. There, the lowland settles in mangroves. They are dying out. Along with them, the gorilla species is disappearing.
The dimensions of the lowland gorilla are comparable to those of the coastal gorilla. But the color of the coat is different. Lowland individuals have brown-gray fur.
Mountain gorilla
The rarest, listed in the International Red Book. There are less than 200 individuals left. Living in remote mountainous areas, the species was discovered at the beginning of the last century.
Unlike other gorillas, the mountain gorillas have a narrower skull and thick and long hair. The forelimbs of the monkey are much shorter than the hind limbs.
Chimpanzee
All live in Africa, in the Niger and Congo river basins. Monkeys of the family are not taller than 150 centimeters and weigh no more than 50 kilograms. In addition, in chipanzees, males and females differ little; there is no occipital carina, and the supraorbital carina is less developed.
Bonobos
Considered the smartest monkey in the world. In terms of brain activity and DNA, bonobos are 99.4% close to humans. Working with chimpanzees, scientists taught some individuals to recognize 3 thousand words. Five hundred of them were consumed by primates in oral speech.
Height does not exceed 115 centimeters. The standard weight of a chimpanzee is 35 kilograms. The wool is dyed black. The skin is also dark, but the bonobo's lips are pink.
common chimpanzee
Finding out how many species of monkeys belong to chimpanzees, you recognize only 2. In addition to bonobos, the common one belongs to the family. He's bigger. Individual individuals weigh 80 kilograms. Maximum height is 160 centimeters.
There are white hairs on the coccyx and near the mouth of the common one. The rest of the fur is brown-black. White hairs fall out during puberty. Before this, older primates consider children to be marked and treat them condescendingly.
Compared to gorillas and orangutans, all chimpanzees have a straighter forehead. At the same time, the brain part of the skull is larger. Like other hominids, primates walk only on their feet. Accordingly, the chimpanzee's body position is vertical.
The big toes are no longer opposed to the others. The length of the leg exceeds the length of the palm.
So we figured it out, what types of monkeys are there. Although they are related to humans, the latter are not averse to feasting on their younger brothers. Many aboriginal peoples eat monkeys. The meat of prosimians is considered especially tasty. Animal skins are also used to make bags, clothes, and belts.
How did this erroneous figure come about? First, only those regions of DNA that encode proteins were compared. and this is only a tiny part (about 3%) of the total DNA. In other words, the comparison simply ignored the remaining 97% of the DNA volume! So much for the objectivity of the approach! Why were they initially ignored? The fact is that evolutionists considered non-coding sections of DNA to be “junk”, that is, "useless remnants of past evolution". And this is where the evolutionary approach failed. Behind last years science has discovered important role non-coding DNA: she regulates the work of genes encoding proteins, “turning on” and “turning off” them. (Cm. )
The myth of 98-99% genetic similarity between humans and chimpanzees is still widespread these days.
It is now known that differences in gene regulation (which are often difficult to even quantify) are as important a factor in determining the differences between humans and apes as the sequence of nucleotides in genes itself. It is not surprising that large genetic differences between humans and chimpanzees continue to be found in initially ignored non-coding DNA. If we take it into account (i.e. the remaining 97%), then the difference between us and chimpanzees increases to 5–8%, and perhaps 10–12% (research in this area is still ongoing).
Secondly, the original work did not directly compare DNA base sequences, but a rather crude and imprecise technique was used, called DNA hybridization: individual sections of human DNA were combined with sections of chimpanzee DNA. However, in addition to similarity, other factors also influence the degree of hybridization.
Third, in the initial comparison, the researchers only took into account base substitutions in DNA, and did not take into account inserts, which contribute greatly to genetic variation. In one comparison of a given section of chimpanzee and human DNA, taking into account insertions, a difference of 13.3% was found
The bias of evolutionists and the belief in a common ancestor played a significant role in obtaining this false figure, which significantly slowed down the receipt of a real answer to the question of why humans and apes are so different.
Therefore evolutionists forced believe that for some unknown reasons, hyperfast evolution occurred on the branch of transformation of ancient apes into humans: random mutations and selection supposedly created for a limited number of generations complex brain, special foot and hand, intricate speech apparatus and other unique human properties (note that the genetic difference in the corresponding sections of DNA is much greater than the overall 5%, see examples below). And this is while we know from actual living fossils, .
So, there was stagnation in thousands of branches (this is an observed fact!), and in the human family tree there was an explosive hyper-fast evolution (never observed)? This is simply unrealistic fantasy! The evolutionary belief is untrue and contradicts everything science knows about mutations and genetics.
- The human Y chromosome is as different from the chimpanzee Y chromosome as it is from the chicken chromosome. In a recent comprehensive study, scientists compared the human Y chromosome with the chimpanzee Y chromosome and found that they "surprisingly different". One class of sequences within the chimpanzee Y chromosome differed by more than 90% from a similar class of sequences within the human Y chromosome, and vice versa. And one class of sequences in the human Y chromosome in general "had no counterpart in the chimpanzee Y chromosome". Evolutionary researchers expected the Y chromosome structures to be similar in both species.
- Chimpanzees and gorillas have 48 chromosomes, while we only have 46. Interestingly, potatoes have even more chromosomes.
- Human chromosomes contain genes that are completely absent in chimpanzees. Where did these genes come from and their genetic information? For example, chimpanzees lack three important genes that are associated with development inflammatory process when a person reacts to illness. This fact reflects the difference that exists between the immune systems of humans and chimpanzees.
- In 2003, scientists calculated a difference of 13.3% between the areas responsible for immune systems. 19 The FOXP2 gene in chimpanzees is not speech at all, but performs completely different functions, exerting different effects on the functioning of the same genes.
- The section of human DNA that determines the shape of the hand is very different from the DNA of chimpanzees. Interestingly, differences were found in non-coding DNA. The irony is that evolutionists, guided by their belief in evolution, considered such sections of DNA to be “junk” - “useless” remnants of evolution. Science continues to discover their important role.
- At the end of each chromosome is a strand of repeated DNA sequence called a telomere. In chimpanzees and other primates there are about 23 kb. (1 kb is equal to 1000 base pairs nucleic acid) repeating elements. Humans are unique among all primates in that their telomeres are much shorter, only 10 kb long. This point is often silent in evolutionary propaganda when discussing the genetic similarities between apes and humans.
@Jeff Johnson, www.mbbnet.umn.edu/icons/chromosome.html
In a recent comprehensive study, scientists compared the human Y chromosome with the chimpanzee Y chromosome and found they were “surprisingly different.” One class of sequences within the chimpanzee Y chromosome was less than 10% similar to a similar class of sequences within the human Y chromosome, and vice versa. And one class of sequences on the human Y chromosome “had no analogue on the chimpanzee Y chromosome.” And in order to explain where all these differences between humans and chimpanzees come from, proponents of large-scale evolution are forced to invent stories about rapid, complete rearrangements and the rapid formation of DNA containing new genes, as well as regulatory DNA. But since each corresponding Y chromosome is unique and completely dependent on the host organism, it is most logical to assume that humans and chimpanzees were created in a special way - separately, as completely different creatures.
It is important to remember that different species of organisms differ in more than just their DNA sequence. As evolutionary geneticist Steve Jones said: “50% of human DNA is similar to bananas, but this does not mean that we are half bananas, either from head to waist or from waist to toe.”.
That is, the evidence indicates that DNA is not everything. For example, mitochondria, ribosomes, endoplasmic reticulum and cytosol are passed unchanged from parents to offspring (protection against possible mutations in mitochondrial DNA). And even gene expression itself is controlled by the cell. Some animals have undergone incredibly strong genetic changes, and yet their phenotype remains virtually unchanged.
This evidence provides tremendous support for reproduction “after its own kind” (Genesis 1:24–25).
Differences in behavior
To introduce you to the many abilities we often take for granted,
An amazing discovery was made by anthropologists. These workers of science were able to prove the seemingly unthinkable: from an anatomical point of view, chimpanzee hands are more perfect than human hands.
This indicates that the common ancestor of chimpanzees and Homo sapiens did not bear noticeable similarities to modern great apes, which are both humans and chimpanzees. In any case, this is exactly what the scientists themselves said on the pages of the Nature Communications publication.
As Owen Lovejoy, an anatomist from the University of Kent, argues on the Science website, the discoveries made by anthropologists since the discovery of the remains of Ardipithecus have fortunately begun to penetrate the consciousness of large sections of the scientific community, which is gradually accepting that we have in common with The chimpanzee ancestor was not at all like them. After all, chimpanzees are adapted to living on high tree branches and eating fruit and therefore can hardly be used as an example of the probable appearance of our common ancestors.
In practice, this statement was proven by a group of paleontologists and anthropologists, led by Sergio Almesihi from the University of Washington. To do this, it was necessary to compare the structure of the hands of Australopithecus sediba, Ardipithecus, humans and chimpanzees, as well as some other modern monkeys and ancient primates.
First of all, scientists were interested in the ratio of length and a number of other anatomical features of the thumb and other parts of the hand. This made it possible to quite accurately not only trace, but also restore various evolutionary connections existing between various types primates.
Thanks to these anatomical characteristics, paleontologists demonstrated that it was the human hand, and not the chimpanzee hand, that was closer in structure to the hand of Ardipithecus, Australopithecus and other ancient anthropoids. Therefore, anatomically, our hands are more primitive than the hands of chimpanzees.
As scientists emphasize, this conclusion not only does not refute Darwin’s theory of evolution, but, on the contrary, further confirms it. This is explained by the fact that with sufficient prosperity, many species of living beings begin to specialize in a certain ecological niche, acquiring, as a result, highly specialized adaptations and at the same time losing universal features, since it is the above-mentioned highly specialized adaptations that help them survive in specific conditions.
Chimpanzees are a good example of this mechanism, in particular their short thumbs and long hands, which are superbly adapted for life on tree branches.
At the same time, chimpanzees are almost incapable of efficiently performing some tasks that are familiar to us, for example, accurately throwing stones.
At the same time, it is the human hand, although it is more primitive and, accordingly, more universal, that gives him the opportunity to confidently solve a lot of different problems, without being capable of performing those specialized tasks that chimpanzees face.
In most other mammals, the grasping organs are a pair of jaws with teeth or two front paws that press together. And only in primates thumb on the hand is distinctly opposed to the other fingers, which makes the hand a very convenient grasping device in which the other fingers act as a single unit. Here is a demonstration of this fact, but before proceeding with the practical experiment, read the following warning:
While performing the exercise below, bend your index finger and DO NOT HOLD middle finger with the other hand, otherwise you may damage the forearm tendon.
After reading the warning, place one palm on a flat surface, back side down. Bend your little finger, trying to touch it to your palm. Please note that, together with the little finger, it rose and ring finger, and its movement occurs automatically, regardless of your will. And in the same way, if you bend your index finger, then your middle finger will follow it. This happens because the hand, in the process of evolution, has adapted to grasp, and to grab something with minimal effort and with maximum speed possible if the fingers are connected to the same mechanism. In our hand, the gripping mechanism is “headed” by the little finger. If you set yourself the task of quickly squeezing your fingers one by one so that they touch your palm, then it is much more convenient to start with the little finger and finish index finger, and not vice versa.
Opposite these fingers is the thumb. This is not uncommon in the animal kingdom, but in few groups this feature extends to all members of the group. Birds of the order Passeriformes have opposable digits, although in some species it is one digit out of four, and in others two digits are opposed to the other two digits. Some reptiles, such as the branch-walking chameleon, also have opposable toes. In invertebrates, grasping organs take various shapes– the claws of crabs and scorpions come to mind first, as well as the forelimbs of insects such as the praying mantis. All these organs are used to manipulate objects (the word "manipulation" comes from the Latin manus, which means "hand").
Our thumb is opposed to the other fingers only on our hands; in other primates this feature extends to all limbs. Humans lost the opposable toe as they descended from the trees to the ground, but the size of the big toe still indicates its special role in the past.
Compared to all monkeys, man has the most dexterous hand. We can easily touch the tip of our thumb with the tips of all our other fingers because it is relatively long. The chimpanzee's thumb is much shorter; they can also manipulate objects, but to a lesser extent. When monkeys hang and swing from a branch, their thumb usually does not wrap around it. They simply fold their remaining fingers into a hook and grab the branch with them. The thumb does not take part in the formation of this “hook”. A chimpanzee only wraps all its fingers around a branch when walking slowly along it or standing on top of it, but even then, like most great apes, she does not so much grab a branch as rely on her knuckles, as when walking on the ground.
Chimpanzee palm and human palm.
Primates have another evolutionary adaptation for manipulation on their hands. In most of their species, the claws have turned into flat nails. Thus, the fingertips are protected from damage, but the fingertips retain sensitivity. With these pads, primates can press on objects, grasp them and feel any surface, even the smoothest, without scratching it. To increase friction, the skin in this area is covered with fine wrinkles. This is why we leave fingerprints.
A pygmy chimpanzee shows off its paw.
Photo: Wikimedia Commons
Anthropologists from George Washington University have found that according to some morphological features hand structure Homosapiens closer to the common ancestor of chimpanzees and humans than the hand of chimpanzees themselves, that is, human hand structure is more primitive than that of its closest living relatives. The work was published in the journal NatureCcommunications.
Scientists have measured the proportions of the thumb in relation to the other four fingers in a variety of living primates, including modern man and other monkeys. In addition, they used several already extinct species of monkeys for comparison, for example, proconsuls ( Proconsul), Neanderthals, as well as Ardipithecus ( Ardipithecus ramidus), close in structure to the common ancestor of chimpanzees and humans, and Australopithecus sediba ( Australopithecus sediba), which some anthropologists consider to be the direct predecessor of the genus Homo.
To analyze the resulting proportions, the researchers used morphometric analysis taking into account phylogeny and complex statistical methods, such as testing several models of alternative evolutionary options. Taken together, these methods made it possible not only to estimate the magnitude of variability in the length and position of the fingers, but also made it possible to determine the direction of their evolution.
It turned out that the common ancestor of chimpanzees and humans had a relatively long thumb and rather short other fingers, which is very similar to the existing ratio of finger sizes in Homosapiens. Thus, humans retained a more conservative variant inherited directly from an ancestor, while chimpanzees and orangutans continued to evolve toward a shortening of the thumb and lengthening of the other four fingers, which made it possible to more effectively grasp and move between tree branches. In other words, the structure of the hand of humans is evolutionarily more primitive than that of other apes (with the exception of gorillas, which, due to their terrestrial lifestyle, have finger proportions similar to humans).
Humans and chimpanzees split from a common ancestor seven million years ago. Among many other differences between the genera, one of the main ones is the setback and long thumb in humans, which allows them to touch the phalanges of any of the other four fingers and make precise and subtle grasping movements. At the same time, chimpanzees' fingers are longer, while the thumb is short and pressed against the palm. For a long time It was believed that the structure of the human hand is a rather late aromorphosis (a progressive change in structure), which became one of the factors in the development of tool activity and, as a consequence, influenced the enlargement of the brain in human ancestors. A new study contradicts this hypothesis.
The scientists’ conclusions are indirectly confirmed by the structure of the hand of Ardipithecus, who lived 4.4 million years ago, which is much closer to that of humans. And also a study by the same group of anthropologists, published in 2010, which substantiates the ability of their closest predecessors, the Orrorin ( Orrorin), making precise grasping movements and manipulations already 6 million years ago, that is, a relatively short time after the separation of chimpanzees and humans.