Monkey wiggle his thumb on his hand. Study: Human hands are more primitive than chimpanzee limbs

An amazing discovery was made by anthropologists. These workers of science were able to prove the seemingly unthinkable: in terms of anatomy, chimpanzee hands are more perfect than human hands.

This indicates that the common ancestor of chimpanzees and Homo sapiens did not bear a marked resemblance to the modern great primates that 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 writes on the website of the journal Science, the discoveries made by anthropologists after the discovery of the remains of Ardipithecus, fortunately, began to penetrate the consciousness of a large section of the scientific community, which is gradually agreeing that our common the chimpanzee ancestor was not at all like them. After all, chimpanzees are adapted to a lifestyle on high tree branches and eating fruits, and therefore can hardly be used as an example of the likely appearance of our common ancestors with them.

In practice, this statement was proved by a group of paleontologists and anthropologists, led by Sergio Almesihi from the University of D. 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 fairly accurately not only trace, but also restore the various evolutionary relationships that exist between different species of primates.

Thanks to these anatomical characteristics, paleontologists have demonstrated that it was the human hand, and not the chimpanzee hand, that was closer in structure to the hand of the 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 losing universal features, since it is precisely the aforementioned 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 excellently adapted to living on tree branches.

At the same time, chimpanzees are almost incapable of doing some of the tasks we are accustomed to, such as 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 ability to confidently solve a lot of different tasks, not being able to perform those specialized tasks that confront chimpanzees.

How many fingers does a monkey have? and got the best answer

Answer from Lali Lali[guru]
Is the question joking? Then
- On two hands! - confirmed Rukodel. - And the monkey's hands are everywhere! - Chucha remembered, - this is how many fingers? - As many as legs! - he said, as Rukodel cut off, then he thought and corrected himself ... - how many notes!
Well, seriously, almost as much as we have, but not in all species.
Their fingers and toes are very flexible, and their thumbs and feet are covered with non-slip skin, similar to humans. Most monkeys have flat nails, but monkeys have claws, a feature they share with some monkey species.
Many monkeys have thumbs and big toes that are opposable to other fingers to accommodate trees and grasp objects. However, this feature varies among varieties. Old World monkeys are usually dexterous and use their fingers to pick up fleas and parasites from each other. In contrast, New World monkeys lack such fingers, although they do have them on their feet. An interesting fact is that one group of Old World monkeys - colobuses do not have thumbs at all, but this does not cause them any inconvenience, and they, like other relatives, easily travel through trees.

Monkeys are primates. In addition to the usual ones, there are, for example, half-monkeys. These include lemurs, tupai, short-toed. Among ordinary monkeys, they are reminiscent of tarsiers. They separated in the Middle Eocene.

This is one of the eras of the Paleogene period, 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-nosed and broad-nosed primates.

tarsier monkeys

Tarsiers - species of little monkeys. They are common in southeast Asia. The primates of the genus have short forepaws, and the heel section on all limbs is elongated. In addition, the brain of tarsiers is devoid of convolutions. In other monkeys, they are developed.

Sirichta

Lives in the Philippines, is the smallest of the monkeys. The length of the animal does not exceed 16 centimeters. The primate weighs 160 grams. With these sizes, the Philippine tarsier has huge eyes. They are round, convex, yellow-green and glow in the dark.

Philippine tarsiers are brown or greyish. The fur of the animals is soft, like silk. Tarsiers take care of the coat, combing it with the claws of the second and third fingers. Other claws are deprived.

Bankan tarsier

Lives in the south of the island of Sumatra. The Bankan tarsier is also found in Borneo, in the rain forests of Indonesia. The animal also has large and round eyes. Their iris is brownish. The diameter of each eye is 1.6 centimeters. If we weigh the organs of vision of the Bankan tarsier, their mass will exceed the weight of the brain of a monkey.

The Bankan tarsier has larger and rounder ears than the Philippine tarsier. They are hairless. The rest of the body is covered with golden brown hairs.

tarsier cast

Included in rare species of monkeys, lives on the islands of Big 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 wool brush at the end of the tail.

Like other tarsiers, the cast has acquired long and thin fingers. With them, the primate wraps around the branches of trees, on which it spends most of its life. Monkeys look for insects and lizards among the foliage. Some tarsiers even encroach on birds.

broad-nosed monkeys

As the name implies, the monkeys of the group have a wide nasal septum. Another difference is 36 teeth. Other monkeys have fewer, at least 4.

Broad-nosed monkeys are divided into 3 subfamilies. These are capuchin-shaped, callimico and clawed. 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 of primates. Therefore, the animals of the group are also called chaintails.

Crybaby

It lives in the north of South, 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 lingering sounds they make.

As for the name of the family, Western European monks who wore hoods were called Capuchins. The Italians called the cassock with him "capuchio". Seeing in the New World monkeys with light muzzles and a dark "hood", the Europeans remembered the monks.

Crybaby is a small monkey up to 39 centimeters long. The tail of the animal is 10 centimeters longer. The maximum weight of a primate is 4.5 kilograms. Females are rarely more than 3 kilos. Even in females, fangs are shorter.

favi

Otherwise referred to as brown. Primates of the species inhabit the mountainous regions of 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-kilogram weight. Occasionally there are individuals weighing 6.8 kilos.

white-breasted capuchin

The second name is an ordinary capuchin. Like the previous ones, it lives on the lands of South America. The white spot on the primate's chest extends over the shoulders. The muzzle, as befits the capuchins, is also light. The "hood" and "mantle" are brown-black.

The "hood" of the white-breasted capuchin rarely descends on the monkey's forehead. The degree of dark coat furryness depends on the sex and age of the primate. Usually, the older the capuchin, the higher his hood is raised. Females "raise" it even in their youth.

Saki Monk

In other capuchins, the length of the coat is uniform throughout the body. The saki monk has longer hairs on the shoulders and head. Looking at the primates themselves and their photo, types of monkeys you begin to discern. So, the "hood" of saki hangs on the forehead, covers the ears. The fur on the face of a capuchin almost does not contrast in color with the headdress.

Saki-monk gives the impression of a melancholic animal. This is due to the lowered corners of the monkey's mouth. She looks sad and thoughtful.

There are 8 types of capuchins in total. In the New World, these are the most intelligent and easily trained primates. They often feed on tropical fruits, occasionally chewing rhizomes, branches, catching insects.

Marmoset broad-nosed monkeys

Monkeys of the family are miniature and have claw-like nails. The structure of the feet is close to that of the tarsiers. Therefore, species of the genus are considered transitional. Marmosets belong to the higher primates, but among them the most primitive.

wistity

The second name is ordinary. In length, the animal does not exceed 35 centimeters. Females are about 10 centimeters smaller. Reaching maturity, primates acquire long brushes of fur near the ears. The decoration is white, the center of the muzzle is brown, and its perimeter is black.

On the big toes of marmosets - oblong claws. With them, primates grab onto branches, jumping from one to another.

pygmy marmoset

The length does not exceed 15 centimeters. A plus is a 20-centimeter tail. The primate weighs 100-150 grams. Outwardly, the marmoset seems larger, because it is covered with a long and thick coat of brown-golden color. The red hue and mane of hair make the monkey look like a pocket lion. This is an alternative name for a primate.

The pygmy marmoset is found in the tropics of Bolivia, Colombia, Ecuador and Peru. With sharp incisors, primates gnaw at the bark of trees, releasing their juices. The monkeys eat them.

black tamarin

Below 900 meters above sea level does not descend. In mountain forests, black tamarins in 78% of cases have a twin. This is how monkeys are born. Fraternal children are brought only in 22% of cases.

From the name of the primate it is clear that it is dark. In length, the monkey does not exceed 23 centimeters, and weighs about 400 grams.

crested tamarin

Otherwise called monkey pinche. On the head of the primate is an erokez-like crest of white, long wool. It grows from forehead to neck. During the unrest, the tuft stands on end. In a good-natured mood, the tamarin is smoothed.

The muzzle of the crested tamarin is bare down to the area behind the ears. The rest of the 20 cm primate is covered with long hair. It is white on the chest and front legs. On the back, sides, hind limbs and tail, the fur is reddish-brown.

piebald tamarin

A rare species, lives in the tropics of Eurasia. Outwardly, the piebald tamarin has a resemblance to the crested one, but there is no that same crest. The animal has a completely bare head. Ears against this background seem large. The angular, square shape of the head is also emphasized.

Behind her, on the chest and front paws - white, long hair. The back, yuoka, hind legs and tail of the tamarin are reddish-brown.

The piebald tamarin is slightly larger than the crested one, weighs about half a kilogram, and reaches a length of 28 centimeters.

All marmosets live 10-15 years. The size and peaceful disposition make it possible to keep representatives of the genus at home.

callimico monkeys

Separated into a separate family recently, before that they belonged to marmosets. DNA tests have shown that callimico is a transitional link. There are many things from capuchins. The genus is represented by a single species.

marmoset

Included in the little-known, rare types of monkeys. Their names and features are only occasionally described in popular science articles. The structure of the teeth and, in general, the skull of a marmoset, like that of a capuchin. The face at the same time looks like the muzzle of a tamarin. The structure of the paws is also marmoset.

The marmoset has thick, dark fur. On the head, it is elongated, forming a kind of cap. To see her in captivity is good luck. Marmosets die outside the natural environment, do not give offspring. As a rule, out of 20 individuals in the best zoos in the world, 5-7 survive. At home, marmosets are healthy even less often.

narrow-nosed monkeys

Among the narrow-nosed there are monkey species in india, Africa, Vietnam, Thailand. Representatives of the genus do not live. Therefore, narrow-nosed primates are commonly called Old World monkeys. They include 7 families.

Monkey

The family includes primates of small to medium size, with approximately the same length of the fore and hind limbs. The first fingers of the hands and feet of monkeys are opposed to the rest of the fingers, like in humans.

Even members of the family have ischial calluses. These are hairless, strained areas of skin under the tail. The muzzles of marmosets are also bare. The rest of the body is covered with hair.

Hussar

Lives south of the Sahara. This is the limit of the range of monkeys. On the eastern borders of the arid, grassy territories of the hussars, their noses are white. Western representatives of the species have black noses. Hence the division of the hussars into 2 subspecies. Both are included in species of red monkeys, because they are colored in orange-scarlet.

Hussars have a slender, long-legged body. The muzzle is also elongated. When the monkey grins, powerful, sharp fangs are visible. The long tail of a primate is equal to the length of its body. The mass 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 the Caribbean. Here, primates merge with the greenery of the tropical forests, possessing wool with a swampy sheen. It is distinct on the back, crown, tail.

Like other monkeys, green ones have cheek pouches. They resemble those of hamsters. Macaques carry food supplies in their cheek pouches.

Javanese macaque

Otherwise called a crabeater. The name is associated with the macaque's favorite food. His fur, like that of a green monkey, casts grassy. Against this background, expressive, brown eyes stand out.

The length of the Javanese macaque reaches 65 centimeters. The monkey weighs about 4 kilograms. The females of the species are about 20% smaller than the males.

Japanese macaque

Lives on Yakushima Island. There is a harsh climate, but there are hot, thermal springs. Near them the snow melts 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 freeze on the shore.

Among the Japanese is larger than others. However, the impression is deceiving. If you cut off the thick, long hair of a steel-gray tone, the primate will be of medium size.

The reproduction of all monkeys is associated with genital skin. It is located in the area of ​​the ischial callus, swells and turns red during ovulation. For males, this is a mating signal.

Gibbon

They are distinguished by elongated forelimbs, bare palms, feet, ears and face. On the rest of the body, the coat, on the contrary, is thick and long. Like macaques, there are ischial calluses, but less pronounced. But gibbons have no tail.

silver gibbon

It is endemic to the island of Java, it does not occur outside of it. The animal is named after the color of its coat. She is gray and silver. The bare skin on the muzzle, hands and feet is black.

Silver of medium size, in length does not exceed 64 centimeters. Females often stretch only 45. The mass of the primate is 5-8 kilograms.

Yellow-cheeked crested gibbon

You cannot tell by the females of the species that they are yellow-cheeked. More precisely, the females are completely orange. On black males, golden cheeks are striking. Interestingly, representatives of the species are born light, then darken together. But during puberty, females, so to speak, return to their roots.

Yellow-cheeked crested gibbons live on the lands of Cambodia, Vietnam, Laos. There primates live in families. This is a feature of all gibbons. They form monogamous couples and live with children.

Eastern hulok

The second name is the singing monkey. She lives in India, China, Bangladesh. Males of the species have bands of white wool above their eyes. On a black background, they look like gray eyebrows.

The average weight of a monkey is 8 kilograms. In length, the primate reaches 80 centimeters. There is also a Western hulok. He is devoid of eyebrows and a little larger, already weighing under 9 kilos.

Siamang

AT species of great apes not included, but among the gibbons is large, gaining 13-kilogram mass. The primate is covered with long, shaggy black hair. It fades to gray near the mouth and on the chin of the monkey.

On the neck of the Siamang is a throat pouch. With its help, the primates of the species amplify the sound. Gibbons have a habit of calling to each other between families. For this, monkeys develop their voice.

pygmy gibbon

There is no heavier than 6 kilograms. Males and females are similar in size and coloration. 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 a balancer.

All gibbons move through the trees, alternately rearranging their front limbs. The manner is called brachiation.

orangutans

Always massive. Male orangutans are larger than females, with hooked fingers, fatty growths on the cheeks in a small guttural sac, like in gibbons.

Sumatran orangutan

Refers to red monkeys, has a fiery coat color. Representatives of the species are found on the island of Sumatra and Kalimantan.

Sumatran is included in types of great apes. In the language of the inhabitants of the island of Sumatra, the name of the primate means "forest man". Therefore, it is incorrect to write "orangutaeng". The letter "b" at the end changes the meaning of the word. In the language of the Sumatrans, 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. Monkey species - a sort of sumo wrestlers, covered in fat. The Bornean orangutan also "owes" its heavy weight to short legs against the background of a large body. The lower limbs of the monkey, by the way, are crooked.

The arms of the Bornean orangutan, as well as others, hang below the knees. But the fatty cheeks of the representatives of the species are especially fleshy, significantly expanding the face.

kalimantan orangutan

It is endemic to Kalimantan. The growth of the monkey is slightly higher than the Bornean orangutan, but it weighs 2 times less. The coat of primates is brown-red. In Bornean individuals, the fur coat is pronounced fiery.

Among the monkeys, the orangutans of Kalimantan are long-lived. The age of some ends in the 7th decade.

All orangutans have a concave skull in the front. The general outline of the head is elongated. All orangutans also have a powerful lower jaw and large teeth. The chewing surface is pronounced relief, as if wrinkled.

Gorillas

Like orangutans, they are hominids. Previously, scientists called so only man and his ape-like ancestors. However, gorillas, orangutans, and even chimpanzees share a common ancestor with humans. Therefore, the classification was revised.

coast gorilla

Lives in equatorial Africa. The growth of the primate is about 170 centimeters, weighs up to 170 kilograms, but often about 100.

The males of the species have a silver stripe running down their backs. The females are completely black. On the forehead of both sexes there is a characteristic redhead.

lowland gorilla

It is found in Cameroon, the Central African Republic and the Congo. There, the plain settles in the mangroves. They are dying out. Together with them, the gorillas of the species also disappear.

The size of the lowland gorilla is commensurate with the parameters of the coast. But the coat color is different. Plains individuals have brown-gray fur.

mountain gorilla

The rarest, listed in the International Red Book. Less than 200 left. Living in remote mountainous areas, the species was discovered at the beginning of the last century.

Unlike other gorillas, the mountain gorilla has a narrower skull, thick and long hair. The forelimbs of the monkey are much shorter than the hind limbs.

Chimpanzee

All live in Africa, in the basins of the Niger and Congo rivers. There are no monkeys of the family above 150 centimeters and weigh no more than 50 kilograms. In addition, males and females differ slightly in shipanzee, there is no occipital ridge, and the supraorbital is less developed.

Bonobo

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 have taught some individuals to recognize 3,000 words. Five hundred of them were used by primates in oral speech.

Growth 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 lips of the bonobo are pink.

common chimpanzee

Finding out how many kinds of monkeys belong to chimpanzees, you will recognize only 2. In addition to the bonobos, the ordinary belongs to the family. He's bigger. Individual individuals weigh 80 kilograms. The maximum height is 160 centimeters.

There are white hairs on the coccyx and near the mouth of the common. The rest of the coat is brown-black. White hairs fall out during puberty. Prior to this, older primates consider marked children, 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 position of the chimpanzee's body is vertical.

The big toes are no longer opposed to the rest. The length of the leg exceeds the length of the palm.

Here we figured it out what are the types of monkeys. Although they have a relationship with people, the latter are not averse to feasting on their younger brothers. Many aboriginal peoples eat monkeys. Particularly tasty is the meat of semi-monkeys. Animal skins are also used, using the material for sewing bags, clothes, belts.

A pygmy chimpanzee shows off its paw.

Photo: Wikimedia Commons

Anthropologists from the George Washington University found that, according to some morphological features, the structure of the hand Homosapiens closer to the common ancestor of chimpanzees and humans than the hand of the chimpanzees themselves, that is, the human hand is more primitive than that of the 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 humans and other apes. In addition, they used for comparison several already extinct species of monkeys, 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 the direct ancestor of the genus Homo.

To analyze the resulting proportions, the researchers used phylogenesis-adjusted morphometric analysis and sophisticated statistical methods, such as testing several models of alternative evolutionary scenarios. Together, these methods made it possible not only to estimate the magnitude of the 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 fingers, which is very similar to the existing ratio of finger sizes in Homosapiens. Thus, humans retained a more conservative variant, inherited directly from their great ancestor, while chimpanzees and orangutans continued to evolve towards shortening the thumb and lengthening the other four fingers, which made it possible to grasp tree branches more efficiently and move between them. In other words, the structure of the human hand is evolutionarily primitive than that of other great apes (with the exception of gorillas, which, due to their terrestrial lifestyle, have finger proportions similar to humans).

Humans and chimpanzees diverged from a common ancestor seven million years ago. Among the many other differences between the genera, one of the main ones is considered to be the set aside and long thumb in humans, which allows you to touch the phalanges of any of the other four fingers and make precise and subtle grasping movements. At the same time, the fingers of a chimpanzee are longer, while the thumb is short and close to the palm. For a long time it was believed that the structure of the human hand is a rather late aromorphosis (progressive change in structure), which became one of the factors in the development of tool activity and, as a result, influenced the increase in the brain in human ancestors. The new study contradicts this hypothesis.

Indirectly, the conclusions of scientists are confirmed by the structure of the hand of the Ardipithecus, who lived 4.4 million years ago, which is much closer to the human one. As well as a study by the same group of anthropologists, published in 2010, which substantiates the ability of their immediate predecessors, orrorins ( Orrorin), to make precise grasping movements and manipulations already 6 million years ago, that is, after a relatively short time after the separation of chimpanzees and humans.

Primate hand

In most other mammals, the grasping organs are a pair of jaws with teeth, or two forepaws that press against each other. And only in primates, the thumb on the hand is clearly opposed to other fingers, which makes the hand a very convenient grasping device in which the remaining fingers act as a single whole. Here is a demonstration of this fact for you, but before proceeding to a practical experiment, read the following warning:

During the exercise described below, bending the index finger, DO NOT HOLD the middle finger with the other hand, otherwise you can damage the tendon of the forearm.

After reading the warning, place one palm on a flat surface with the back side down. Bend the little finger, trying to touch it to the palm. Pay attention to the fact that along with the little finger, the ring finger also rose, and its movement occurs automatically, regardless of your will. And in the same way, if you bend your index finger, then the middle one will move after it. This is due to the fact that the hand in the process of evolution has adapted to gripping, and it is possible to grab something with minimal effort and with maximum speed 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 in turn so that they touch the palm of your hand, then it is much more convenient to start with the little finger and end with the index finger, and not vice versa.

These fingers are opposed by the thumb. In the animal kingdom, this is not uncommon, but in a few groups this feature extends to all members of the group. Opposite fingers are present in birds of the order Passeriformes, although in some species it is one finger out of four, and in others two fingers oppose another two fingers. Some reptiles, such as the branch-walking chameleon, also have opposable toes. In invertebrates, the prehensile organs take many forms, most notably the claws of crabs and scorpions, and 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 opposes other fingers only on the hands; in other primates, this feature extends to all limbs. Humans lost the opposing toe when 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 easily touch the tip of the thumb with the tips of all other fingers, because it is relatively long. The thumb of a chimpanzee is considerably 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 the rest of their fingers into a hook and grab onto a branch with them. The thumb does not take part in the formation of this "hook". The chimpanzee grasps a branch with all his fingers only when walking slowly along it or standing on top of it, but even then, like most great apes, he does not so much grasp the branch as rests on the knuckles of his fingers, as when walking on the ground.

Chimpanzee hand and human hand.

Primates have another evolutionary tool for manipulation on their hands. In most of their species, the claws have evolved into flat nails. Thus, the fingertips are protected from damage, but the fingertips retain sensitivity. With these pads, primates can press on objects, grab them, and feel any surface, even the smoothest, without scratching it. To increase friction, the skin in this area is covered with fine wrinkles. That is why we leave fingerprints.