The human hand turned out to be older than the monkey. From an anatomical point of view, the hand of a chimpanzee is more developed than that of a human.How many fingers does a monkey have on its feet?

Our Yoni's arm is significantly (almost twice) longer than his leg.

Of the three parts that make up the arm, the hand is the shortest, the shoulder is longer and the forearm is the longest.

When the chimpanzee is maximally erect, its arms descend well below the knees (Table B.4, Fig. 2, 1), reaching with the tips of the fingers to the middle of the tibia.

The chimpanzee's hand is covered almost along its entire length with rather thick, coarse, pitch-black hair, which, however, has different directions, length and density on different parts of the hand.

On the chimpanzee's shoulder, this hair is directed downward and is generally thicker and longer than that of the forearm and hand; on the outer back of the shoulder, they are more abundant than on the inner, where light skin is translucent; there is almost no hair in the armpit.

On the forearms, the hairs are directed upwards, and again they are longer and thicker than the hairs of the brush; on the inner side of the forearm, especially near the elbow and at the base of the hand, they are much less common than on the outer side.

On the back of the hand, the hair reaches almost to the second phalanx of the fingers, the inner side of the hand is completely devoid of hair and is covered with skin somewhat darker than the skin of the face (Table B.36, Fig. 1, 3).

Raceme very long: its length is almost three times its width; its metacarpal region is somewhat longer than its phalanx region.

The palm is long, narrow, its length is ⅓ longer than its width.

Fingers

The fingers of the hand are long, strong, high, as if inflated, somewhat narrowed towards the ends. The main phalanges of the fingers are more slender and thinner than the middle ones; terminal phalanges are much smaller, shorter, narrower and thinner than the main ones. The third toe is the longest, the first toe is the shortest. According to the degree of the descending length, the fingers can be placed in the following row: 3rd, 4th, 2nd, 5th, 1st.

Examining the fingers of the hand from the back, it should be noted that they are all covered with thick, lumpy skin, covered with hair only on the main phalanges.

On the borders of the main and middle phalanges, on four long fingers (No. 2-5), we observe strong swelling of the skin, forming, as it were, soft-callous thickenings; much smaller swellings are found between the middle and terminal phalanges. Terminal phalanges end with small shiny, slightly convex, dark brown nails bordered on the outer edge by a narrow darker stripe.

In a healthy animal, this nail border barely protrudes beyond the flesh of the terminal phalanx of the fingers and is timely nibbled when the nails grow back; only in sick animals do we usually notice overgrown nails.

Let's move on to describing the lines of the hands of our chimpanzee.

Hand lines

If we take the chimpanzee hand described by Schlaginhaufen "om, which belongs to a young female chimpanzee, as the initial comparative sample, then the development of lines on the palm of our Yoni turns out to be much more complicated. (Table 1.2, Fig. 1, (Table B.36, Fig. 3) ).

Table 1.2. Chimpanzee and human palm lines and soles

Rice. 1. Lines of the palm of the chimpanzee Yoni.
Rice. 2. Lines of the palm of a human child.
Rice. 3. Lines of the sole of the chimpanzee Yoni.
Rice. 4. Lines of the soles of a human child.

Table 1.3. Individual variation of palm and sole lines in chimpanzees

Rice. 1. Palm lines of the left hand ♂ chimpanzee (Petit) 8 years old.
Rice. 2. Palm lines of the right hand ♂ chimpanzee (Petit) 8 years old.
Rice. 3. Palm lines of the right hand ♀ chimpanzee (Mimosa) 8 years old.
Rice. 4. Lines of the sole of the left hand ♀ chimpanzee (Mimosa) 8 years old.
Rice. 5. Palm lines of the left hand ♀ chimpanzee (Mimosa) 8 years old.
Rice. 6. Lines of the sole of the right foot ♀ chimpanzee (Mimosa) 8 years old.
Rice. 7. Lines of the sole of the left foot ♀ chimpanzee (3 years old).
Rice. 8. Palm lines of the left hand ♀ chimpanzee (3 years old).
Rice. 9. Lines of the sole of the right foot ♂ chimpanzee (Petit).

The first horizontal line (1st, or aa 1) is sharply expressed in Ioni and has the same position and shape as in the diagram, but it is somewhat complicated by additional branches; soon after its departure from the ulnar part of the hand (just at the point of intersection of it with the vertical line V, located opposite the 5th toe), it gives a sharp spur (1a), heading towards the base of the inner edge of the phalanx of the second finger, resting on the first transverse line at its foundations.

The second horizontal line (2nd, or bb 1), located in its original part one centimeter proximal to the previous one, begins with a small fork from the vertical V line; this fork soon (at the point of its intersection with the vertical IV line) joins into one branch, which at the point of its meeting with the vertical III line makes a sharp slope towards the horizontal 1st line at the point of its intersection with the vertical II line (dd 1) located opposite the axis of the index finger.

The third horizontal line (3rd or cc 1), located in its original part of centimeters 5 proximal to the previous line of the 2nd, starts from the very edge of the ulnar part of the hand and tends to go upwards along its entire length, at the points of intersection with V and IV vertical sludge is already only a centimeter from the 2nd line, and at the meeting point with the vertical III it completely merges with the previous (2nd) line. Incidentally, it should be mentioned that the third line at the beginning of its path at the ulnar edge of the hand takes a short horizontal branch, and in the middle of its path (in the center of the palm) it is torn and horizontal line 10 should be considered its continuation (a detailed description of which given below).

Of the other larger, transversely running lines of the palm, the following should be mentioned.

The fourth line (4th, or gg 1) begins on the ulnar edge of the palm at the point of origin of the 3rd horizontal line and goes in an oblique position straight down to the 1st line (or FF 1), crosses this last and gives three small branches , of which two (4a, 4b) fork-like diverge at the bottom of the tubercle of the thumb, and one (4c) goes down to the 7th and 8th wrist lines (ii 1).

Almost next to the initial segment of the 4th line, there is a groove parallel to it - the 5th horizontal line, which (at the meeting point of the 5th horizontal with V vertical) obliquely goes down, crosses the III vertical line and reaches almost to the first spur (1a) the first vertical line I.

The sixth horizontal line (6th) begins one centimeter lower than the previous one, going in a straight, almost horizontal, slightly rising line, ending shortly after its intersection (at the meeting point of the 6th with line VII) with two weak branches 6a and 6a.

The seventh horizontal line (7th, or hh 1) - at the base of the hand with 2 small branches directed obliquely and upward along the lowest part of the pinky tubercle.

The eighth horizontal line (8th, or ii 1) is short, weak, almost adjacent to the previous one, only located lower and more radially.

The horizontal 9th ​​weakly expressed short line runs in the very center of the palm 1 cm proximal to the 10th horizontal segment.

The tenth horizontal line (10th), located at the top and in the middle of the palm, parallel to the 2nd horizontal line (bb 1) in its middle section (located between IV and II vertical lines), spaced from the previous one at a distance of 1 cm, represents on my view is an excerpt from line 3 (cc 1).

Referring to the lines cutting through the palm in vertical and oblique positions, we should mention the following: I vertical line (FF 1) starts at the top at the first transverse line (I, or on aa 1) at a distance of 1 cm from the radial edge of the hand and, wide arc bordering the elevation of the thumb, goes down almost to the line of the wrist (7, hh 1).

On its way towards the central part of the brush, this I vertical line gives off several branches: the first branch from it, according to our designation 1a, departs at the level of the end of the segment of its upper third, almost against the weak transverse (9th) line, goes obliquely inward to the medial part of the palm, crossing the 4th and 6th horizontal lines of the hands; the second branch (1b) I of the vertical line departs from it 2 mm lower than the previous one (1a) and has almost the same direction as it, but ends slightly lower than the previous one, reaching the 7th and 8th wrist lines (hh 1, ii 1 ) and, as it were, cutting them.

Inside from the 1st vertical line, just from the depression near the thumb, there is a sharp groove VII, the most prominent of all the available lines of the hand; this line, with a steep arc enveloping the top of the thumb tubercle, crosses slightly below the middle of the Ia and Ib lines (FF 1) and continues downward in an oblique direction, reaching the wrist lines (7th), cutting line 4 (gg 1 ) and lb.

Of the other more or less prominently expressed vertically directed lines of the hand, four more should be mentioned. A short (II) line (corresponding to ee 1 according to Schlaginhaufen "y), located in the upper quarter of the hand, going just in the direction of the axis of the second toe, starts almost from the gap between the 2nd and 3rd fingers and goes straight down, merging with its the lower end with line I (FF 1) (just in the place where the segment of the 10th horizontal line approaches it).

Line III is one of the longer lines on the palm (corresponding to dd 1 according to Schlaginhaufen "y).

It begins at the top with a weakly pronounced groove directly opposite the axis of the middle finger, slightly cutting the process from the transverse line of the 1st (aa 1), with a sharp line it crosses line 1 and line 2 (at the point where the latter merges with the 3rd line), crosses line 9, 10 and, deviating towards the ulnar part of the hand, passes exactly at the point where the lines of the 4th and 6th crosses and goes further even lower, crossing the end of the 5th line and branches from the 7th horizontal, reaching the very line of the wrist (7 th).

IV vertical line (kk 1 in the terminology of Schlaginhaufen "a), located opposite the axis of the 4th toe, begins as a weak groove (visible only under certain illumination) extending from the gap between the 3rd and 4th digits and going straight down ; this line becomes more pronounced just above the line 2. Going down below, this IV vertical line successively intersects the 3 and 9 horizontal lines and imperceptibly vanishes, slightly not reaching the 5th horizontal line.

V vertical line, the longest of all vertical lines of the hand, is placed against the axis of the 5th finger and starts from the transverse line at its base, goes down, sequentially cutting the transverse lines 1, 2, 3, 4, 5, 6 and, as it were, meeting oblique lines extending from the 7th line located on the wrist.

In good light, in the upper part of the hand, above line 1 (aa 1), a small horizontal bridge x is visible between the vertical lines IV and V.

Of the other more noticeable brush lines, mention should be made of the long oblique line VI, cutting through the lower part of the brush, starting from the lower branch of the 2nd line and going obliquely downward to the points of its intersection with three lines la, lb and 6th horizontal and further down to the place of its confluence with 1c, heading towards the wrist line (7th).

We now turn to describing the lines at the base of the fingers.

At the base of the thumb we find two obliquely diverging lines that meet in the notch of the hand: VII and VIII; from the lower of these lines - VIII, enveloping the thumb, there are four radially diverging downward smaller lines, intersected in the middle of the thumb tubercle with a thin transverse fold; the upper of these lines, VII, has already been described.

At the base of the index and little fingers, we find three lines, separated from each other at the outer edges of the fingers and converging at the inner corners between the fingers. Slightly above the base of the middle and ring fingers, we find single transverse lines.

In addition to these lines, we find three additional arcuate lines connecting pairwise different fingers: 2nd with 3rd (a), 4th with 5th (b), 3rd with 4th (c).

1. From the outer edge of the second toe, an arcuate line (a) extends towards the inner edge of the third toe, matching the transverse line at its base.
2. From the outer edge of the fifth toe (namely from the median transverse line of the base) there is an arcuate line (b) going to the inner edge of the fourth toe, matching the transverse line of the base of this latter.
3. An arcuate line (c) connects the bases of the third and fourth fingers, extending from the corner between the 2nd and 3rd fingers, heading towards the angle between the fourth and fifth toes (namely, to the transverse line at the base of the ring finger).

We also find double parallel lines at the base of the second phalanges of the fingers (from the 2nd to the 5th).

At the base of all nail phalanges of the fingers (1-5), we again have single transverse lines.

Thus, the palm of our Yoni, especially in its central part, is furrowed with a thin binding of 8 vertically directed and 10 horizontally directed lines, which can be deciphered only after an unusually minute and careful analysis.

The relief of our Yoni's palm is much more complex, not only when compared with the hand of a chimpanzee proposed by Schlaginhaufen, which belongs to a young female, in which we see at most 10 main lines, but also when compared with other sketches of the hands of young chimpanzees at my disposal: a young chimpanzee who has lived since 1913 in the Moscow Zoo (judging by its appearance somewhat younger than Ioni) (Table 1.3, Fig. 8), an 8-year-old female chimpanzee nicknamed “ Mimosa "(Table 1.3, Fig. 3 and 5) and the 8-year-old chimpanzee Petit (Table 1.3, Fig. 1, 2) kept (in 1931) in the Moscow Zoo.

In all these cases, as the figures show, the total number of main lines does not exceed 10.

Even the most cursory examination of all the presented hands shows that despite the large variation in the relief of the palms, the loss of some lines and the displaced position of others, despite the difference in the drawings on the right and left hand of the same individual (Fig. 1 and 2, Fig. 3 and 5 - Table 1.3), - yet we can easily decipher the names of all lines by analogy.

On all five handprints, the most indisputable and constant position is the horizontal transverse line 1 (aa 1), the 2 nd horizontal line merges with the first in its final stage (as is the case in Fig. 8, 1), then it goes completely independently (as in the Schlaginhaufen diagram "a) in Fig. 3 and 5, it gives only a branch to the first horizontal (as is the case in the case of Fig. 2).

The 3rd horizontal line (cc 1) varies more than the previous ones, both in magnitude (cf. Fig. 8, 5 with all others) and in location: while in Fig. 1, 3, 5, 8 it has a completely isolated position (and in the latter case gives only a weak twig upward), in Fig. 2 (as in Ioni), it falls into the second horizontal line, completely merging with it in the radial part of the hand.

The 4th horizontal line, clearly pronounced in Yoni, is also definitely revealed in Fig. 5; in fig. 8 and 2, we analogize it only approximately, judging by the direction from the tubercle of the little finger to the bottom of the tubercle of the thumb and by the triple branching (it is possible that we mix it with the 5th or 6th horizontal). This last transverse line 6 is indisputably precisely localized only in Fig. 1 and 5, having exactly the same position and direction as Joni, and in fig. 2 and 3, we tend to fix only its initial segment, located on the tubercle of the little finger, heading from bottom to top.

Of the rest of the horizontal lines presented in the attached figures, mention should be made of the lines at the base of the wrist, presented either in larger (as in Fig. 8), then in smaller numbers (as in Table 1.3, Fig. 1, 2, 3) , and line 9, passing in the middle of the palm, available in one and only one of all 5 cases (namely in Fig. 3).

Turning to the vertical lines of the hands, we must say that they are all easily determined by analogy, on the basis of the topographic position and mutual relation with the lines of the hands already described, although in details they reveal some deviations from what Joni has.

The most constant position of the line I (as we see in Fig. 8, 2, 1); in fig. 5, 3 we see how this line is shortened and tends to approach (Fig. 5), and perhaps to merge with line VII (Fig. 3).

Of the other vertical lines, III (present in all 5 figures and only sometimes deviates somewhat from its usual position against the axis of the third finger) and V, going to the little finger, are well pronounced.

In contrast to what Yoni has, this last V line in three cases does not retain its position until the end (against the axis of the 5th finger), but goes, in the direction of VI, as if merging with this last line, taking in the segments all other vertical lines (IV, III, II, I), as is especially noticeable in Fig. 8, 3 and partly in Fig. 1. In two cases (Fig. 2 and 5) this V line is completely absent.

IV vertical line with a single exception (Fig. 1) is present, but varies greatly in size and shape. It is very short (as in case 8 and 1), then it is interrupted and long (Fig. 5), then it is sharply deviated from the usual position against the axis of the 4th finger (Fig. 3). Line II, going to the index finger, is observed only in one case (Fig. 3).

] The view is supported by the diagram and description of Schlaginhaufen "a, who believes that the line cc 1 consists of 2 parts.

It should be emphasized that the difficulties of this analysis increase when operating with a hand cast from a dead animal in the form of a wax dummy, where the relief of the lines changes sharply depending on the lighting conditions. That is why, for the correct orientation and when noting the lines, it was necessary to trace each line under all-round illumination, looking through it from all possible points of view and only in this way establishing the true path of its following: starting and ending points, as well as all possible connections with the nearest contacting linear components.

All sketches of hands at my suggestion and with my complicity were made from nature by the thin artist. VA Vatagin, in the 2nd case - from the dead, in the 3rd and 4th - from live specimens.

I take this opportunity to gratefully acknowledge the assistance rendered to us (artist Vatagin and me) in sketching by M. A. Velichkovsky, who helped us in handling live chimpanzees when sketching their arms and legs.

Often the opinion is imposed on us that man descended from a monkey. And that science has discovered such a similarity in human DNA with chimpanzees, which leaves no doubt about their origin from a common ancestor. Is it true? Are humans really just evolved apes? Consider the differences between a monkey and a person.

It is noteworthy that human DNA allows us to do complex calculations, write poetry, build cathedrals, walk on the moon, while chimpanzees catch and eat fleas from each other. As information accumulates, the gap between humans and apes becomes more and more evident. Listed below are just a few of the differences that cannot be explained by minor internal changes, rare mutations, or survival of the fittest.

1 Tails - where did they go? There is no intermediate state between the presence of a tail and its absence.

2 Our newborns are different from baby animals. Their senses are quite developed, the weight of the brain and body is much greater than that of monkeys, but with all this, our babies are helpless and more dependent on their parents. Baby gorillas can stand up to 20 weeks after birth, and human babies only 43 weeks after birth. During the first year of life, a person develops functions that young animals have even before birth. Is this progress?

3 Many primates and most mammals produce vitamin C on their own. As the "strongest" we have obviously lost this ability "somewhere in the path of survival."

4 The feet of the monkeys are similar to their hands - their big toe is mobile, directed to the side and opposed to the rest of the fingers, resembling a thumb. In humans, the big toe is directed forward and is not opposed to the rest, otherwise we could, having thrown off our shoes, easily lift objects with the help of the big toe, or even begin to write with our foot.

5 Monkeys have no arch in their feet! When walking, our foot, thanks to the arch, absorbs all loads, shocks and impacts. If a person descended from ancient monkeys, then the vault should have appeared in his foot “from scratch”. However, the spring vault is not just a small detail, but a complex mechanism. Without him, our life would be completely different. Just imagine a world without bipedal locomotion, sports, games and long walks!

6 A person does not have a solid hairline: if a person shares a common ancestor with monkeys, where did the thick hair from the monkey body go? Our body is relatively hairless (lack) and completely devoid of tactile hair. No other intermediate, partially hairy species are known anymore.

7 Human skin is rigidly attached to the muscle frame, which is characteristic only of marine mammals.

8 Humans are the only terrestrial creatures capable of consciously holding their breath. This, at first glance, "insignificant detail" is very important, since an essential condition for the ability to speak is a high degree of conscious control of breathing, which in our country is not similar to any other animal living on land. Desperate to find the land's "missing link" and based on these unique human properties, some evolutionists have seriously suggested that we are descended from aquatic animals!

9 Among primates, only humans have blue eyes and curly hair.

10 We have a unique speech apparatus that provides the finest articulation and articulate speech.

11 In humans, the larynx occupies a much lower position in relation to the mouth than in monkeys. Due to this, our pharynx and mouth form a common "tube", which plays an important role as a speech resonator. This ensures better resonance - a prerequisite for pronouncing vowel sounds. Interestingly, a drooping larynx is a disadvantage: unlike other primates, humans cannot eat or drink and breathe at the same time without choking.

12 The thumb of our hand is well developed, strongly opposed to the rest and very mobile. Monkeys have hook-shaped hands with a short and weak thumb. No cultural element would have emerged without our unique thumb! Was it a coincidence or a design?

13 Only man is inherent in true upright posture. Sometimes, when the monkeys are carrying food, they can walk or run on two legs. However, the distance they travel in this way is rather limited. In addition, the way monkeys move on two limbs is completely different from people walking on two legs. This particular human approach requires a complex combination of many of the skeletal and muscular features of our thighs, legs and feet.

14 People are able to keep their weight on their feet while walking because our hips converge to the knees, forming a unique 9-degree bearing angle with the tibia (in other words, we have "inverted knees"). Conversely, chimpanzees and gorillas have widely spaced, straight legs with an almost zero bearing angle. These animals, while walking, distribute their body weight on the feet, rocking the body from side to side and moving with the help of the familiar “monkey gait”.

15 In its complexity, the human brain is far superior to that of monkeys. It is approximately 2.5 times larger than the brain of higher monkeys in volume and 3-4 times in mass. A person has a highly developed cerebral cortex, in which the most important centers of the psyche and speech are located. Unlike monkeys, only man has a complete Sylvian furrow, consisting of anterior horizontal, anterior ascending and posterior branches.

Based on site materials

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

While doing the exercise described below, bend your index finger, DO NOT KEEP the middle finger with the other hand, otherwise the tendon of the forearm could be damaged.

After reading the warning, place one palm with the back of your hand down on a flat surface. Bend your little finger, trying to touch it to the palm. Pay attention to the fact that along with the little finger, the ring finger also raised, and its movement occurs automatically, regardless of your will. And in the same way, if you bend the 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 grip, and it is possible to grip something with minimal effort and 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 one by one so that they touch the palm, 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 few groups this feature applies to all members of the group. Opposing fingers are found in birds from the order of passerines, although in some species this is one finger out of four, while in others two fingers are opposed to the other two fingers. Some reptiles, such as a chameleon moving along branches, also have opposing fingers. In invertebrates, grasping organs take on various forms - the claws of crabs and scorpions, as well as the front limbs of insects such as the praying mantis, come to mind. All these organs are used to manipulate objects (the word "manipulation" comes from the Latin manus, which means "hand").

Our thumb is opposed to other fingers only on the hands; in other primates, this feature extends to all limbs. Humans lost their 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 lightly 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 grab it. They simply fold the rest of their fingers with a hook and grab a branch with them. The thumb does not take part in the formation of this "hook". The chimpanzee grasps the branch with all its fingers only when it slowly moves along it or stands on top of it, but even then, like most apes, it does not so much grasp the branch as rests on the knuckles of the fingers, as when walking on the ground.

Chimpanzee palm and human palm.

The primates have another evolutionary manipulation device on their hands. In most of their species, the claws have turned into flat nails. Thus, the tips of the fingers are protected from damage, but the pads of the fingers remain sensitive. With these pads, primates can press on objects, grab them and touch 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.

Hand of primates

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

While doing the exercise described below, bend your index finger, DO NOT KEEP the middle finger with the other hand, otherwise the tendon of the forearm could be damaged.

After reading the warning, place one palm with the back of your hand down on a flat surface. Bend your little finger, trying to touch it to the palm. Pay attention to the fact that along with the little finger, the ring finger also raised, and its movement occurs automatically, regardless of your will. And in the same way, if you bend the 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 grip, and it is possible to grip something with minimal effort and 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 one by one so that they touch the palm, 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 few groups this feature applies to all members of the group. Opposing fingers are found in birds from the order of passerines, although in some species this is one finger out of four, while in others two fingers are opposed to the other two fingers. Some reptiles, such as a chameleon moving along branches, also have opposing fingers. In invertebrates, grasping organs take on various forms - the claws of crabs and scorpions, as well as the front limbs of insects such as the praying mantis, come to mind. All these organs are used to manipulate objects (the word "manipulation" comes from the Latin manus, which means "hand").

Our thumb is opposed to other fingers only on the hands; in other primates, this feature extends to all limbs. Humans lost their 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 lightly 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 grab it. They simply fold the rest of their fingers with a hook and grab a branch with them. The thumb does not take part in the formation of this "hook". The chimpanzee grasps the branch with all its fingers only when it slowly moves along it or stands on top of it, but even then, like most apes, it does not so much grasp the branch as rests on the knuckles of the fingers, as when walking on the ground.

Chimpanzee palm and human palm.

The primates have another evolutionary manipulation device on their hands. In most of their species, the claws have turned into flat nails. Thus, the tips of the fingers are protected from damage, but the pads of the fingers remain sensitive. With these pads, primates can press on objects, grab them and touch 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.