Why do giraffes have spotted skin? Why does a giraffe need spots Why does a giraffe have a long neck

Giraffes are one of the most colorful and unusual animals on our planet.

Their appearance is so unique that it is simply impossible to confuse brightly spotted giraffes with their long necks with other artiodactyls.

The spotted coloring on a giraffe's skin has many important functions for their survival.

Half a century ago, biologists suggested that the pattern is individual for each giraffe, like human fingerprints, and is inherited.

Recently, scientists from Pennsylvania State University (USA) confirmed this hypothesis using modern computer image processing methods. Moreover, these were observations of a large number of animals of different generations.

The individual pattern on a giraffe's coat consists of dark spots that stand out against the background of a lighter base color, and it does not change throughout the animal's life..

This makes it possible for specialists studying giraffe behavior to distinguish individuals from each other, regardless of their age.

Computer image analysis and statistical methods analysis complex drawings allowed us to explain why giraffes need this bright spotted skin:

Experts have confirmed a long-standing hypothesis - the giraffe pattern is passed down through the maternal line , Phys.org reports. This concerns at least two parameters: how close each individual spot is to a circle and how smooth and continuous the contours of the spot are.

It was also discovered amazing fact: the larger the spots in a newborn and the more irregular shape, the greater the baby’s chances of survival. Most likely, irregular large spots provide better camouflage from predators. Although, despite the camouflage and devoted protection of the mother, only 25–50% of young giraffes reach adulthood.

Several years ago, scientists proved that giraffes do not belong to one species of the “giraffidae” family, as was previously thought - a genetic analysis of 200 artiodactyls proved that there are four different subspecies of giraffes, which almost never mix with each other.

The researchers who carried out the analysis said that giraffes different types genetically different from each other in the same way as brown bears from whites.

Instead of just one species, Giraffa camelopardalis, scientists have proposed the following names for the new species. Animals living in South Africa, Namibia and Botswana, dignify southern giraffes Giraffa giraffa; living in Tanzania, Kenya and Zambia - Maasai giraffes G. tippelskirchi; in Somalia and Southern Ethiopia - reticulated G. reticulata and, finally, living in scattered groups in the center and east of the African continent - northern giraffes G. camelopardalis. The northern giraffe also has a subspecies that lives in Ethiopia and South Sudan.

It is interesting to remember that the height of the male reaches 5.5-6.0 m (with about 1/3 of the length being the neck), and the weight sometimes exceeds one ton. Females tend to be shorter and lighter.

Giraffes can see their tall relatives at a distance of up to a kilometer.

These animals run well: in case of urgent need, they develop speed like racehorse– up to 55-60 km/h, although they prefer to stroll slowly. In addition, giraffes jump very well and overcome barriers up to 1.5 meters!

Did you know that the scientific name of the giraffe is camelopardalis? It comes from the Latin cameleopard (camel+leopard). In ancient Rome they were given this name because the animals were large, like a camel, and with spots like a leopard.

We have already written about these animals earlier, now it’s time to tell you why a giraffe needs a spotted color.

Giraffe spotting challenge for a long time was unclear to scientists. Back in the middle of the last century, biologists suggested that spots could hide young animals from predators, help thermoregulation, and intraspecific communications.

Thus, in 1968, the legendary Canadian animal researcher Anne Innis Dagg showed that the pattern of spots in giraffes is inherited. But it was difficult to conduct a full-fledged study that would accurately tell about the “rules” of the heritage.

The fact is that the skin of giraffes has even pigmentation, but the spots can be of very different sizes, locations and shapes - from almost round to “blobs” with sharp corners. Therefore, it was not even possible to track its inheritance and variability among different generations.

In a new study, experts connected artificial intelligence (AI) to solving this problem, which helped reveal the secret of giraffe spots.

In this work, we analyzed animal survival data and photographs of Masai giraffe spots. "We showed that spot patterns influence survival and are inherited from mother to child," explained Penn State University professor Derek Lee.

Thirty-one pairs of females and their calves were analyzed, as were records of 258 giraffes under four months of age.

Scientists, together with AI, assessed the color patterns of animals using 11 characteristics that took into account the size, shape and color of spots. The neural network showed that two of the 11 color characteristics (the degree of roundness of spots and the clarity of their boundaries) coincided in females and their offspring, indicating the direct inheritance of these properties.

The study also found that the survival rate of newborn giraffes during the first months of life is associated with the number and location of spots on their fur: the larger they are and the more randomly located, the lower the mortality rate. Thus, survival rate increased by 7.5%.

The main cause of mortality in newborn Masai giraffes is predators: so survival figures support the hypothesis that the coloring of these animals plays the role of camouflage - at least for the young, experts concluded.

There is historical evidence that in those days when the Sahara was still covered with a plant carpet and inhabited by all the current inhabitants of the savannah, the ancient Egyptians caught wild giraffes in it and brought them to their cities.

Story

For the first time in Ancient Rome The giraffe was brought by Julius Caesar in 46 BC. The inhabitants of Rome called this cute creature a camelopard, mistakenly assuming that it was a cross between a camel (“camelus”) and a leopard (“pardus”). The word “giraffe” is of Arabic origin, and has been used in the Russian language for centuries in both the masculine and feminine genders. IN modern language the norm is to use this word only in masculine.

Modern Europe The giraffe was introduced only in the century before last, when in 1826, the Viceroy of Egypt Pasha Mehmet presented one young giraffe to the kings of France and Great Britain.

Body structure

The giraffe's body has an amazing anatomical structure. His body is short and dense, his back is sloping, his head is very small with surprisingly large light eyes, large soft and extremely mobile ears and two strange growths on his forehead. These growths are called “ossicones” or “horns”. A newborn giraffe already has ossicones. They are formed in the embryonic stage separately from the frontal bones.

But the giraffe has an extremely long neck and legs, making it the longest and relatively the shortest mammal on the planet. Thus, its head is about 5-6 meters above the ground, while the body height does not exceed 4 meters.

Since the head of this wonderful beast is two meters above the level of its heart, the latter has to pump up an unusually high column of blood. It’s not for nothing that the thickness of the wall of the giraffe’s carotid artery is 12 millimeters, which allows it to withstand colossal arterial pressure, which is twice as much in a giraffe as in a human.

There may be a misconception that such a length of the neck is achieved due to the huge number of vertebrae, but this is not at all the case. All mammals, including humans, have seven cervical vertebrae, but they are of different sizes. So, small rodents have tiny vertebrae, while a giraffe has very large ones.

Why does a giraffe have a long neck?

So why does a giraffe need this? Long neck? The answer is very simple - with its help, he plucks leaves and shoots from the tops of trees. In African savannas it has many herbivorous neighbors - antelopes, zebras and many others. And each of them has to dine on his own “floor.” It is inconvenient for a giraffe to pluck low-growing grass, but it can easily reach the very tops of trees, and at such a height it has no competitors.

Why does a giraffe need horns?

Horns because it is a cloven-hoofed ruminant.

Males and females have a pair of short, blunt horns covered with skin on the top of their heads. In males they are more massive and longer - up to 23 cm. Sometimes there is a third horn, on the forehead, approximately between the eyes; in males it is more common and more developed. Two bony outgrowths in the upper part of the back of the head, to which the neck muscles and ligaments are attached, can also grow greatly, resembling the shape of horns, which are called posterior, or occipital. In some individuals, usually old males, both three true horns and two posterior ones are well developed; they are called "five-horned" giraffes. Sometimes in old males other bony outgrowths are observed on the skull.

Although the baby giraffe is born without horns, the place of their future appearance is marked by tufts of black hair, under which there is cartilage. Gradually, the cartilaginous tissue ossifies, turning into small horns, which then begin to grow. Tufts of black fur remain with the giraffe for several years, then they wear off and disappear.

If, nevertheless, there is a need to find out the seniority in the herd, a kind of duel takes place between the largest males. It begins with a challenge: the applicant for the highest rank goes towards the enemy with an arched neck and lowered head, threatening him with his horns. These, in general, harmless horns, together with a heavy head, constitute the giraffe’s main weapon in the fight for primacy.

Why does a giraffe need spots?

Masking coloring. The pattern and color of the giraffe are amazingly beautiful - on a light yellow background there are various dark spots that vary greatly. It is impossible to find two completely identically colored giraffes. Just like a human fingerprint, the spotted pattern of each individual giraffe is unique.

The giraffe's variegated coloring seems too bright, but in reality it perfectly camouflages the animals. It should be taken into account that animals are more often found in a group of umbrella acacias against the background of burnt foliage of bushes. And under the sheer rays of the sun, a mosaic of shadows and sun spots is created on the trees and animals, which combines with the spotted pattern of the giraffe and, as it were, softens its outline among the bright highlights of the foliage.

Active protection. In order to live in African savannah, its inhabitants require excellent vision and keen hearing, the ability to run quickly and actively defend themselves. All this can be attributed to giraffes, which are perfectly equipped for life in the savannah - they are not only provided with camouflage colors and patterns, but also see far and hear well. Yes and natural enemies giraffes have few, since among the predators only lions can attack them, and even then only in a group. But the giraffe is successfully defended against a single enemy by its enormous height, durable skin, powerful force hoof strike. However, the main enemy of this beautiful animal was, and still remains, the human hunter.

In the group of herbivores, giraffes, due to their high growth, excellent vision and behavioral characteristics, play the role of a “sentinel”. They are able to see from a distance a predator from the cat family silently sneaking in the tall grass.

Sometimes giraffes take flight and can reach speeds above 50 km/h. And then their nearby relatives follow their example. But more often, having warned other animals about the danger with a few swings of their tail, giraffes fearlessly go out to meet the predator.

Giraffe tongue

Many herbivores are known to use their tongues to capture food, but none of them do it as masterfully as the giraffe. Its tongue is very long and flexible, reaching a length of about half a meter. Slowly and lazily, the giraffe picks the topmost young shoots from the tops of mimosas, which are his favorite delicacy. At the same time, his lips do not suffer from mimosa thorns, just as the lips of a camel do not suffer from thorns. The tip of its muzzle is covered with special hairs - vibrissae, which sense the approach of thorns.

The giraffe rarely nibbles steppe grass, preferring only succulent shoots that are rich in moisture. Getting all the necessary liquid from food, giraffes can be quite far from water sources. However, during the dry season they go in search of a reservoir.

To drink water, the giraffe has to take strange poses. Sometimes he spreads his front legs wide and tilts the front of his body and neck forward, other times he has to bend his legs or put one of them forward and the other back.

Giraffe Dream

Giraffes sleep in an equally interesting position. Lying first on their chest, during sleep they turn over on their side, tuck one or both front legs to their stomach, throw their neck back and place their head on the back thigh. Giraffes' sleep is very light and short-lived. They can go without sleep for several days and simply rest while standing.

Giraffe running and dynamics

A giraffe's speed at a gallop can reach 56 kilometers per hour, while its movements seem smooth, as if in slow motion. The neck serves as a balancer and controls the rhythm of its movements. At a slow pace, a giraffe can only move at an amble, only in this case can it long legs don't touch each other.

Unfortunately, few of the giraffes brought to our latitudes endure captivity for long. Many of them quickly die from a specific bone disease called “giraffe disease.” Most likely, it is caused by lack of exercise and inappropriate food. However, in Lately the situation has improved slightly, which is apparently due to a more competent approach to creating conditions for keeping these animals.