Sperm whale (scientific name: physeter macrocephalus): The head is huge, the lower jaw is small, and only the lower jaw has teeth. Mainly eats squid. With a body length of up to 18 meters and a weight of more than 50 tons, it is the largest toothed whale, with a head that can occupy 1/3 of the body, no dorsal fin; it has strong diving ability, and is the deepest diving and longest diving mammal. It is fish-like in size and breathes with its lungs. The neck is short, the head seems to be connected to the trunk; the cervical spine is healed; the nostrils are nozzles, located at the end of the snout, the forelimbs are finned, the forearms degenerate, the palms become longer, the number of toes increases, but the toes and claws are not visible from the outside; the hind limbs are degenerate; the tail resembles a fish, with a horizontal tail fin, swimming by the tail swing.
Sperm whales are 11–20 m long for males and 8.2–18 m for females with an adult weight of 25–45 tonnes; juveniles are 4 m long at birth and weigh up to 500 kg. Compared to the body, the sperm whale's head appears disproportionately heavy and large, with the largest brain in the animal kingdom, while the tail appears both light and small, which makes the sperm whale's body resemble a large tadpole. The head of an adult male whale is particularly prominent, generally accounting for four to one-third of the total length of the body, and the appearance is roughly square. Its nostrils are located on either side of the front left of the top of this huge box. Unusually, although the sperm whale has two nostrils, only the left nostril is unblocked for breathing, while the right nostril is naturally blocked, which causes the sperm whale to always be on the right side of the body when it surfaces to breathe, and the water mist column is sprayed at an angle of about 45 ° to the left front. The lower jaw of the sperm whale is short and narrow, rod-like, and shorter than the upper jaw of the head, which is very disproportionate and difficult to distinguish when viewed from the side. Its jaw is small but its bones are strong and powerful. Several conical teeth grow on the mandibular maxillofacial surface, which are more than 20 cm long around the lower jaw. The sperm whale's upper jaw, on the other hand, has no teeth, only small cone-shaped holes pierced by the teeth of the lower jaw.
The body is streamlined and does not need to be in the mouth, all have teeth, and are non-exchangeable teeth, single roots, single pointed, and homomorphic. The snout is very long, the nasal bone, frontal bone, and parietal bone move in the direction of the back, and the skull is asymmetrical to the left and right, especially in the nostril area. One of the outer nostrils, located on the top of the head, is commonly known as the air vent. The anterior ribs are bicephalic ribs. No clavicle. The forelimbs are fin-shaped and suitable for swimming. The belt and hind limbs are degenerate, and the caudal fin is horizontal. The respiratory tract and digestive tract are completely separated. Bicornal uterus, a pair of mammary glands, located in the groin. The penis can be completely indented into the body wall, and the testicle nine is located in the abdominal cavity. [3] The surface of the skin in the posterior segment of the body usually has many horizontal folds, which, unlike the smooth and firm skin of other cetaceans, the skin folds in obese individuals are usually less pronounced. The vent hole is located in front of the head and to the left, as the sperm whale's skull is extremely heavily skewed to the left during development. The dorsal area has a low bulge relative to the dorsal fin, followed by a series of smaller ridges that extend all the way to the caudal fin, with a thick caudal stalk. The pectoral fin is short and broad, with a rounded tip and a triangular caudal fin with straight edges. Sperm whales vary greatly in sex and body size, with adult males usually one-third longer than females and weighing up to twice as much as females. The lower jaw has twenty to twenty-six pairs of large, conical teeth, and the teeth in the upper jaw are small and buried in the gums, or have only alveolars.
The back of the sperm whale has a dark grey to dark skin tone that appears tan in bright sunlight. The abdomen is silvery gray and white. The upper lip and jaw are white near the tongue. There are usually irregular white patches in the flanks.
The sperm whale skeleton is characterized by a huge skull, about 1/3 of the total length of the skeleton. The crest of the skull forms a huge depression, the wing bone is developed, the occipital bone heals, and there is no tear bone; the left and right sides of the skull are obviously asymmetrical, and the left bone nostrils are larger than the right; the left nasal bone is developed, and the right nasal bone is degenerated; the left front jaw is shorter, reaching only the nostrils backwards, and the right anterior maxilla extends beyond the nostrils to reach the posterior wall of the cranial concave. Atlantoaxial free, the other 6 cervical vertebrae healed; the shoulder blades are taller than wide, the 11th pair of ribs are underdeveloped, flat, straight, short, and the most special of cetacean bones.
Sperm whales are widely distributed in the ice-free waters of the world, and their footprints can be found from the equator all the way to the poles, mainly in the sea between 70 latitudes. Among them, the deep and productive sea area is the most important. The distribution of adult males and females is significantly different, females usually inhabit water depths above 1,000 meters and latitudes below 40 degrees, but in the North Pacific Ocean up to about 50 degrees north latitude; males follow their mothers in tropical waters when they are young, and will gradually move to higher latitudes after growing up, and the larger and older the male whales, the higher the range of distribution, and even close to the polar ice floes. Females and juvenile sperm whales usually stay in an area of 1,000 km wide for at least 10 years, with adult males moving much more widely.
activity
Sperm whales like to live in groups, often by a small number of male whales and large groups of female whales, baby whales into dozens of large groups, or even two or three hundred, every year due to reproduction and foraging for north and south migration, its swimming speed is very fast, up to more than ten nautical miles per hour, and sperm whales have excellent diving ability, diving up to 2200 meters deep, and can stay underwater for two hours.
Because sperm whales have a long dive time, they have little chance of seeing them on the surface of the sea, but their special shape and jets make them less likely to be confused with other large cetaceans. The interval sperm whales that dive twice float or swim slowly on the surface of the sea resemble giant driftwood; the jets that tilt to the left of about 45 degrees are low and bush-like. There are often jumping waves or whale tails. Sperm whales float on the surface of the water to sleep, sleep is very heavy, often floating on the surface of the water for several hours. Ships are stopped at sea at night. During rafting, large whales are often found sleeping quietly next to the boat.
Long-term stable female whale populations form the core unit of sperm whale society, such small groups of up to 12 adult females, accompanied by their female and young male offspring, generally swimming speed of 5 to 3 nautical miles per hour, up to 7-12 nautical miles when frightened. Elderly male whales, 12 to 17 meters long, swim alone in the ocean, rarely finding communication that lasts more than 1 day. Whole schools of sperm whales sometimes run aground on the beach.
body temperature
Whales are thermostatic animals with an average body temperature of 35.5 °C, and in mammals its body temperature is low, 1.4 °C lower than that of humans. Whales bathe the sea for life. Although the marine environment is relatively stable, the climate has changed with severe cold and heat, the sea area has the difference between the equatorial poles, the sea has the difference between the surface and the deep water, and the water temperature will also change greatly. For example, the surface water temperature of the tropical sea is about 28 ° C, the cold sea near the poles is 0 ° C, and at a depth of 1,000 meters, even in the equatorial sea in the middle of summer, the water temperature is only 4-5 ° C or even 0 ° C. Whales sometimes haunt near the equator, sometimes migrate to polar seas, and from time to time dive thousands of meters underwater, and also bathe in cold and warm. Sometimes the water temperature is unevenly lower than the body temperature of the whale, and the heat of the whale's body easily escapes into the cold water. And the heat transfer speed of water is very fast, 25 times faster than air, and the whale is swimming non-stop in the water, which is equivalent to water flowing through the surface of the whale body at a certain speed, just like the cold wind skimming the body, the heat dissipation is faster.
Covering the body with a very thick insulator is the best way to maintain body temperature, but as soon as the animal arrives in the water, the hair is soaked by the water, which not only loses the insulation effect, but also increases the resistance to movement, so the hair of the whale gradually disappears: and replaces it with a very thick subcutaneous fat layer. Fat is a poor conductor of heat, and its thermal conductivity is much lower than that of water. The subcutaneous fat of the whale is equivalent to a fat quilt on the body, forming a natural insulation barrier. In cetaceans, sperm whales are on average 13-18 cm thick. The thicker the subcutaneous fat, the stronger the thermal insulation.
If the skin of cetaceans is 1 cm thick, for every 1 °C decrease in temperature, every square centimeter of area, heat dissipation is 0.5 per second. 0005 card. By this standard, cetaceans lose more heat per hour than they can produce in the same amount of time. therefore. Whales in cold water, must continue to exercise all day long, improve metabolic rate, produce heat, maintain its body temperature, even sleep inches are not completely stationary, and sleep time is short.
On the whale's caudal fin, dorsal fin and flipper limbs, the structure of the circulatory system is very special. Its arteries are divided into countless parallel arterioles, and each arteriole is surrounded by many longitudinal venous vessels, forming a bundle of blood vessels. This is a trans heat exchange system, which is a structure that regulates body temperature. Because the fins are thinner, they are easily affected by the outside water temperature and become cold. According to the measurement, that is, the high temperature of the arterial blood is precooled by the vein before reaching the surface of the fin, and the venous blood with low temperature is preheated by the artery before returning to the heart, in other words, the arterial blood flowing to the surface of the fin is first transferred to the venous blood on the way back to the body, thereby reducing the loss of heat.
Whales also produce too much heat in their bodies after a long period of intense exercise or in warm waters, but there are no sweat glands on its skin, and there is a thick layer of fat under the skin that acts as an insulating barrier, and it is impossible to expel excess heat through this route. Its excess heat is dissipated through the upper part of the fin. The temperature reaches the flipper, dissipating too much heat, and no longer transfers some of the heat to the vein in the middle of the way. This network of blood vessels that regulates body temperature is not only on the fins, but also on the skin of the whole body. When animals dive, due to the low temperature in the deep water, the blood on the surface of the body decreases, thereby inhibiting the loss of heat; on the contrary, when the body temperature rises, the blood on the surface of the body increases, accelerating the release of heat. Blood circulation on the surface of the body may be dominated by water temperature, that is, when the water temperature is high or the temperature in the body rises, the blood on the surface of the body increases, accelerating heat dissipation; conversely, blood flow is reduced, inhibiting heat dissipation.
Feeding habits
The main diet is large squid, octopus, and fish, while squid and octopus mainly eat shrimp, crabs, crustaceans and fish. Consume foods the equivalent of 3 to 3.5 percent of body weight per day.
Male whales also feed on gun squid , although prey preferences are usually larger , such as the king squid . A 12-meter-long, 200-kilogram king squid was once found in the stomach of a sperm whale. Scratches and circular suction cup marks are sometimes found on the mouth and body of sperm whales, which may be scarred by the tentacles of gun squid when fighting such large prey, and there have been records of suction cup marks up to 11 cm in diameter.
Sperm whales reproduce slowly, with females not maturing until they are 9 years old, while males mature longer. Adult females are conceived only once every 4-6 years, one baby per baby, and rarely twins, and their lactation period is as long as two years. Breeding grounds are generally in tropical and subtropical waters between 40 degrees north and south latitudes, and although some mating occurs between mid-winter and summer, mostly in spring: in the Northern Hemisphere, mating periods may run from January to July, with a peak of March to May; sperm whale mating periods in the Southern Hemisphere are between August and December, concentrated in October. The gestation period is at least 1 year or more, and may be up to 18 months. Females breastfeed for at least 2 years, sometimes longer. The lifespan is about 70 years, up to more than 100 years. Each litter produces only 1 litter, occasionally 2 litters, the cubs are 4 to 5 meters long, the lactation period is 1 to 2 years, and the maximum life span can reach 70 years. Sperm whales are male and female, and baby sperm whales generally begin to mature around the age of 10 after birth.