The marine fauna of our planet is very rich and diverse. Its inhabitants are living beings of various kinds and forms of existence. Some are friendly and non-threatening, while others are aggressive and dangerous. The smallest representatives of the aquatic fauna are inaccessible to ordinary human vision, but there are also real sea giants that amaze the imagination with their power and gigantic size. These include the good old hero of children's fairy tales, but in reality – a powerful and dangerous marine predator – a sperm whale.
The origin of the species and description
Sperm whales are one of the most ancient marine inhabitants of our planet. The age of the fossil remains of their distant ancestors – squalodont toothed whales – is about 25 million years. Judging by the powerful jaws with huge, highly developed teeth, these giants were active predators and fed on large prey – primarily their closest relatives – small whales.
Approximately 10 million years ago, sperm whales appeared, very close in their appearance and lifestyle to the modern species. During this time, they have not evolved significantly, and still remain at the top of the food chain of the underwater world.
Video: Sperm Whale
The sperm whale is a marine mammal, the largest member of the toothed whale family. Due to its characteristic appearance, it cannot be confused with any other cetacean species. This predator has truly gigantic dimensions – it reaches a length of 20-25 meters and weighs about 50 tons.
If the fate is that the head of these animals occupies up to a third of the total body length, then the origin of the species name becomes clear – “ sperm whale”. It is assumed that it has Portuguese roots, and is formed from the word “cachalote”, which, in turn, is a derivative of the Portuguese “cachola”, which means “big head” in translation.
Sperm whales do not live alone. They gather in large groups, the number of which reaches hundreds, and sometimes thousands of individuals. So it is more convenient for them to hunt, take care of their offspring and defend themselves from natural enemies.
In search of prey, these sea giants dive to great depths – up to 2000 meters, and are able to stay there without air for up to an hour and a half.
Appearance and Features
The appearance of the sperm whale is very characteristic and has a number of features that distinguish it from other cetaceans. The sperm whale is a real giant, the largest representative of the order of toothed whales. The length of an adult male is about 20 meters or even more. As for the weight of the sperm whale, the average value of this value is the range from 45 to 57 tons. Sometimes there are also larger individuals weighing up to 70 tons. And experts say that earlier, when the sperm whale population was more numerous, the weight of some males approached 100 tons.
The difference between the sizes of males and females is very significant. Females are almost twice as miniature. Their maximum parameters: length 13 meters, weight 15 tons. A characteristic feature of the body structure of the sperm whale is an exorbitantly huge head. In some individuals, it is up to 35% of the total body length. It is proportional to the size of the head and mouth of the whale, which allows the animal to hunt the largest prey.
An interesting fact: the sperm whale is the only marine mammal that can swallow a person whole.
The lower jaw of the sperm whale is able to open very wide outward, forming a right angle with respect to the body. The mouth is located in the lower part of the head of a mammal, as if “under the chin”, if we draw an analogy with the structure of the human head. There are more than two dozen pairs of huge and strong teeth in the mouth, they are located mainly on the lower, “working” jaw.
The eyes are located symmetrically on the sides, closer to the corners of the mouth. The diameter of the eyeball is also very significant, about 15-17 centimeters. There is only one respiratory opening and it is displaced to the anterior left side of the animal's head. This is the “working nostril”, which gives out a fountain of air when you exhale. The second, right nostril ends in a valve and a small cavity into which the sperm whale gains air before diving to a depth. The air from the right nostril cannot go out.
The skin of the sperm whale is usually gray in color. The back is dark, but the belly is much lighter, almost white. The skin is wrinkled all over the body of the animal, with the exception of the back. There are several deep folds on the neck. It is assumed that their presence helps the animal to place the largest prey in the mouth. The folds straighten out – and the internal cavity increases, accommodating a large amount of food.
But the main feature of sperm whales is the spermaceti sac located in the upper part of the head and making up 90% of its weight. It is a kind of formation inside the skull of an animal, limited by connective tissue and filled with a special substance – spermaceti. Spermaceti is a waxy substance formed from animal fat. It turns into a liquid state when the body temperature of the sperm whale rises and solidifies when cooled.
Studies have shown that the whale “adjusts” the temperature regime on its own, regulating the flow of blood to the spermaceti sac. If the temperature reaches 37 degrees, then the spermaceti melts, its density decreases and provides the sperm whale with an easy ascent. And the chilled and hardened spermaceti helps the animal dive to the depth.
The sperm sac also performs the most important function of echolocation for the sperm whale, distributing the directions of sound waves, and serves as a good shock absorber during fights with relatives or attacks by enemies.
Where does the sperm whale live?
The habitat of sperm whales can safely be called the entire oceans, with the exception of polar waters. These giant animals are thermophilic, their largest number is observed in the tropics. When summer comes in one of the hemispheres, the range of sperm whales expands. In winter, when the ocean waters get colder, the animals return closer to the equator.
Sperm whales are deep sea mammals. They practically do not occur near the coast, they prefer to be many kilometers from the coastline – where the depth of the seabed exceeds 200-300 m. Their movements in the waters of the World Ocean depend not only on the season, but also on the migration of cephalopods, which are their main food. Meeting with sperm whales is possible wherever large squids are found.
It is noted that males occupy larger territories, while the range of females is limited to waters, the temperature of which during the year does not fall below 15 degrees. The researchers suggest that such herds are also joined by lone males who have not managed to collect a harem for themselves. These giants are also found in our waters. For example, in the Barents and Okhotsk Seas there is enough food for them, so a few herds live there quite comfortably, as in the seas of the Pacific basin.
What does the sperm whale eat?
The sperm whale is the largest predator among marine mammals. It feeds mainly on cephalopods and fish. Moreover, fish in the food absorbed by the whale is only five percent. Usually these are katrans and other types of medium-sized sharks. Among cephalopods, the sperm whale prefers squids, while octopuses make up a very small part of its prey.
The sperm whale hunts at a depth of at least 300-400 meters – where most of the mollusks and fish that they eat live, and where it has practically no food competitors. Despite the fact that a whale can stay under water for quite a long time, he has to make several dives to get enough. For proper nutrition, the animal needs about a ton of food per day.
The sperm whale does not chew food, but swallows it whole. Only the largest specimens can be torn apart. Judging by the sucker marks left by squid in the whale's stomach, cephalopods remain alive there for some time.
An interesting fact: a case is known when a sperm whale swallowed a squid so huge that it did not fit in the whale's belly, and its tentacles stuck to the outside of the whale's snout.
Females are less voracious than males, and almost do not eat fish, preferring to eat cephalopods. Among the sperm whales found by whalers with an empty stomach, a larger percentage are females, which indicates the difficulties of subsistence for them during periods of caring for offspring.
The method of obtaining food by the sperm whale does not exclude accidental prey or unusual objects from entering its stomach. Sometimes these are seabirds that the whale never intentionally hunts, and sometimes they are rubber boots, fishing tackle, glass and plastic bottles and other underwater debris.
The sperm whale is the only giant-sized marine mammal that can dive to considerable depths and stay there for a long time. This is due to the anatomical features of his body, consisting of a large amount of fatty tissues and liquids, almost not subject to compression under the pressure of the water column, as well as due to the whole system of oxygen accumulation necessary for underwater breathing. The whale makes a supply of air in the voluminous bag of the right nasal passage. A significant amount of oxygen accumulates in the adipose tissue and muscles of the animal.
Usually sperm whales dive to a depth of 400 to 1200 meters – where most of their food lives. But studies have shown that these giants can dive much deeper – up to 3000 and even up to 4000 meters from the surface of the water. Sperm whales do not hunt alone, but in packs of several dozen individuals. Acting in concert, they drive the prey into tight groups to make it easier to absorb it. Such a hunting strategy determines the herd lifestyle of sperm whales.
And sperm whales hunt almost constantly. One after another, they make dives lasting an average of 30-40 minutes, and then rest at the surface of the water for some time. Moreover, the sleep period in these animals is rather short, and is only about 7% of the time during the day, that is, less than two hours. Sperm whales sleep, sticking their huge snout out of the water, hanging motionless in complete stupor.
An interesting fact: during sleep, both hemispheres of the brain cease to be active in sperm whales at once.
Due to the presence of a spermaceti sac, the sperm whale is endowed with the ability to effectively use high-frequency and ultrasonic echolocation. With its help, he tracks down prey and navigates in space, because he hunts where sunlight does not penetrate at all.
Scientists also suggest that echolocation can be used by sperm whales as a weapon. It is possible that the ultrasonic signals emitted by them have an effect on large cephalopods, leading them into confusion, disorientation in space and making them easy prey.
Social structure and reproduction
Males have a more active social life than females. The main function of females is to reproduce offspring, feeding and caring for them. While males are much more concerned about their status among relatives, often proving their right to superiority in fierce fights, sometimes leading to injuries and injuries.
Most often, fights occur during the rutting season, when males become aggressive and, in an effort to create their own harem, fight for the attention of females. About 10-15 females usually keep near one male. 13-14 months after conception, females give birth to offspring. Usually one cub is born. A newborn sperm whale reaches a length of 5 meters and weighs about 1 ton. Until the age of two, the baby is breastfed and under the care of the mother.
An interesting fact: the mammary glands of a nursing female sperm whale can hold up to 45-50 liters of milk.
At about 10 years of age, sperm whale cubs become completely independent. Young males gather in so-called bachelor groups. They stay out of the herd, by themselves, and do not get into fights unless absolutely necessary. By the age of 8-10, sperm whales become sexually mature, capable of producing offspring.
Natural enemies of sperm whales
Given its formidable appearance and great power , with which nature has awarded sperm whales, there are not so many enemies that threaten their lives in natural nature. But they are.
First of all, these are the famous killer whales, the legendary marine predators – killer whales. Endowed with remarkable intelligence, killer whales are famous for their fighting strategies, allowing them to prey on mammals that are much larger than them. Using group tactics, killer whales attack female sperm whales and their cubs. Trying to protect offspring, the female is doubly vulnerable and often becomes prey herself.
Juveniles that have strayed from the herd also sometimes get lunch with killer whales. However, if sperm whales catch signals of an attack on their relatives, they rush to the rescue, ready to engage in a fierce battle and fight not for life, but for death. Such battles most often leave killer whales without prey. Dealing with angry adult male sperm whales is an almost impossible task.
The sperm whale has no other large enemies. But harm to his health can also be caused by small underwater inhabitants – endoparasites that settle in the body of an animal. The most dangerous is the roundworm placentonema, which lives and develops in the placenta of females.
An interesting fact: the parasitic roundworm placentonema can reach a length of 8.5 meters.
On the surface of the body of the sperm whale, the penella parasitizes, and on the teeth – barnacle cancer. In addition, during the life of the animal's skin is overgrown with numerous mollusks and crustaceans, but they do not cause any damage to the life and health of the sperm whale.
Population and species status
The sperm whale is a very attractive object whaling. Whale oil, spermaceti, teeth and meat are highly valued by humans, so for a long time the population was subjected to ruthless destruction for industrial purposes.
The result was a rapid decrease in the number of sperm whales, and in the 60s of the last century, due to the threat of the complete extermination of the species, a strict restriction on its prey was introduced. And in 1985, a complete ban on fishing came into force. Now only Japan has a limited quota for sperm whales for scientific and research purposes.
Thanks to these measures, the sperm whale population is currently maintained at a fairly high level, although accurate data on the number of individuals of this species are not available or vary greatly. Different experts call figures from 350 thousand to one and a half million individuals. But everyone unanimously argues that there are no exact figures for the number of sperm whales in the wild. This is due, first of all, to the difficulty of marking and tracking animals, since they live at very great depths.
Today, the sperm whale population has the status of “vulnerable”, i.e. there is no increase in livestock or it is very small. This is primarily due to the long cycle of reproduction of offspring.
Sperm whale protection
The sperm whale population is subject to many dangers. Despite their impressive size and natural power, these sea giants also suffer from adverse external conditions, like other marine life.
Here are some factors that prevent animals from living and developing freely in their natural environment, increasing the population of the species:
- Anthropogenic factor in the form of pollution and noise present in areas of oil and gas development;
- Noise from passing ships that interferes with natural echolocation;
- Accumulation persistent chemical pollutants in coastal waters;
- Ship collisions;
- Getting into fishing gear and entanglement in underwater electrical cables.
These and other phenomena adversely affect the number of sperm whales in their natural habitat. Although at present experts note some increase in the number of these animals, but it does not exceed 1% per year of the total population.
This trend is very fragile, which is why the sperm whale still has the status of a protected animal. To prevent the extinction of the species, Russian and international experts have developed special conservation programs in relation to the conservation of the number of sperm whales and its growth. Constant monitoring is carried out to prevent poaching of animals. To date, the sperm whale is listed in the Red Book of Russia and in many conservation lists of other countries.
Sperm whales are unique marine mammals, hardy and powerful predators. In the past, when they were actively hunted, they gained a reputation for aggressive and brutal killers. On their account, indeed, there are many sunken whaling boats and even ships, dozens of lives of whalers. But the manifestation of aggression was only a response to the excessive greed of a person who is eager to get such valuable whale products.
Today, when hunting for sperm whales is prohibited almost everywhere, such bloody stories are no longer heard. The sperm whale lives and finds its own food without causing the slightest damage to people. And in order to preserve the natural balance, we should do the same.