Physeter macrocephalus

Sperm Whale, with no subspecies, has the largest brain in the animal kingdom.

Sperm whales like to live in groups, often with a few male whales and a large group of female whales and calves forming a large group of more than dozens, or even two or three hundred. They migrate north and south every year for reproduction and foraging. They swim very fast, up to more than ten nautical miles per hour, and they have excellent diving ability, diving up to 2,200 meters, and can stay underwater for two hours.

Because sperm whales dive for a long time, there is little chance of seeing them on the sea surface, but their special appearance and jet make them difficult to be confused with other large whales. Between two dives, sperm whales will float or swim slowly on the sea surface, and their appearance is very similar to huge driftwood; the jet tilted to the left at about 45 degrees is low and bush-like. There are often actions of jumping up and hitting the waves or hitting the waves with the whale's tail. Sperm whales sleep on the water surface, and they sleep very deeply, often floating quietly on the water surface for several hours. Ships stop sailing at sea at night. During drifting, large whales are often found sleeping quietly beside the boat.

Long-term stable female whale groups constitute the core unit of sperm whale society. Such small groups can have up to 12 adult female whales, accompanied by their female and young male offspring. They generally swim at a speed of 5 to 3 nautical miles per hour, and can reach 7 to 12 nautical miles when frightened. Old male whales with a length of 12 to 17 meters mostly swim alone in the ocean, and it is rare to find that they communicate for more than 1 day. Entire groups of sperm whales sometimes get stranded on the beach.

Whales are warm-blooded animals with an average body temperature of 35.5℃, which is relatively low among mammals, 1.4℃ lower than human body temperature. Whales bathe in the sea for their entire lives. Although the marine environment is relatively stable, the climate changes from extreme cold to extreme heat, the sea areas are different between the equator and the poles, and the sea water has differences between the surface and deep water, so the water temperature will also change greatly. For example, the surface water temperature of tropical seas is about 28℃, and the cold sea areas near the poles are 0℃. At a depth of thousands of meters, even in the equatorial seas in midsummer, the water temperature is only 4-5℃ or even 0℃. Whales sometimes appear near the equator, sometimes migrate to the polar seas, and often dive hundreds of meters underwater, and they will also experience cold and warmth. Sometimes the water temperature is much lower than the whale's body temperature, and the heat from the whale's body can easily dissipate into the cold water. Moreover, the heat transfer speed of water is very fast, 25 times faster than that of air. In addition, whales are constantly swimming in the water, which is equivalent to water flowing through the surface of the whale's body at a certain speed, just like a cold wind passing over the body, and the heat dissipation is faster. The sperm whale has a thick layer of insulation on its body, which is the best way to maintain body temperature. However, once the animal enters the water, its hair is soaked by water, which not only loses its heat-insulating function, but also increases the resistance to movement, so the hair on the whale's body gradually disappears: it is replaced by a thick layer of subcutaneous fat. 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 layer of fat blanket on the body, forming a natural insulation barrier. Among whales, the average thickness of sperm whales is 13-18 cm. The thicker the subcutaneous fat, the stronger the thermal insulation performance.

Sperm whales mainly feed on large squid, octopus, and fish, while squid and octopus mainly eat shrimp, crabs, and other crustaceans and fish. Every day, they consume food equivalent to 3% to 3.5% of their body weight. Male whales also feed on squid, but their preferred prey is usually larger, such as giant squid. A giant squid that was still intact, 12 meters long and weighing 200 kilograms was once found in the stomach of a sperm whale. Sperm whales sometimes have scratches and round suction cup marks on their mouths and bodies, which are probably scars left by the tentacles of squid when fighting with such large prey. There have been records of suction cup marks with a diameter of up to 11 centimeters.

Sperm whales reproduce slowly. Female whales mature at the age of 9, while male whales mature longer. Adult female whales only conceive once every 4-6 years, with one calf per litter, and twins are rare. Their lactation period is as long as two years. The breeding grounds are generally in tropical and subtropical waters between 40 degrees north and south latitude. Although some mating occurs in mid-winter to mid-summer, most occur in spring: in the northern hemisphere, the mating period may be from January to July, with a peak from March to May; the mating period of sperm whales in the southern hemisphere is between August and December, concentrated in October. The gestation period is at least 1 year, and may be as long as 18 months. The female whale breastfeeds for at least 2 years, sometimes longer. The lifespan is about 70 years, and the longest can reach more than 100 years. Only one calf is born per litter, and occasionally two calves are seen. The calf is 4 to 5 meters long, with a lactation period of 1 to 2 years, and the longest lifespan can reach 70 years. Sperm whales are one male and multiple females. After the baby sperm whale is born, it generally begins to mature at around 10 years old.

Commercial hunting of sperm whales began in the early 18th century, and over the next two centuries, it expanded into a global industry. At its peak in the 1830s, about 5,000 sperm whales were killed each year worldwide. From the second half of the 19th century, the hunting of sperm whales decreased as oil production reduced the demand for sperm whale oil and the sperm whale population declined. After World War II, 20th-century whalers, equipped with sonar and new whaling guns, resumed the hunt for sperm whales. As many as 30,000 were killed each year, causing some populations to shrink significantly. Commercial hunting stopped after the International Whaling Commission implemented a moratorium on whaling in 1988. There are no precise estimates of the number of sperm whales in existence worldwide, but based on estimates of sperm whale numbers in a few regions, a rough estimate is that the total population may be between 200,000 and 1.5 million. Sperm whales are not currently hunted in large numbers and appear to be relatively safe in the short to medium term. Without being actively hunted, sperm whales have very little interaction with humans: most of their habitat is far from land, and their food sources (mainly deep-water squid) are few and far between. Some populations, such as those in the western North Atlantic, which are virtually unaffected by modern whaling, appear to be healthy, with fairly high population densities and satisfactory reproduction (National Marine Fisheries Service 2000).

Listed in the IUCN Red List of Threatened Species in 2008, ver3.1 - Vulnerable (VU).

Listed in Appendix I, Appendix II and Appendix III of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) 2019 Edition.

Listed in China's "National Key Protected Wildlife List" (February 5, 2021) Level 1.

Protect wildlife and eliminate game.

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Sperm whales are widely distributed in ice-free waters around the world. Their footprints can be found from the equator to the poles. They mainly live in the seas between 70 degrees north and south latitude. The deep and productive seas are the most abundant. There is a significant difference in the distribution of adult male and female whales. Female whales usually live in waters with a depth of more than 1,000 meters and within 40 degrees latitude, but in the North Pacific Ocean, they can reach about 50 degrees north latitude. Male whales live with their mothers in tropical waters when they are young. After growing up, they will leave the group and gradually move to higher latitudes. The larger and older the male whales are, the higher the latitudes they are distributed, and they may even be close to the polar ice zones. Female whales and juvenile sperm whales usually stay in an area 1,000 kilometers wide for at least 10 years, while adult male whales move much more widely.

The male sperm whale is 11-20 meters long, the female is 8.2-18 meters long, and the adult weight is 25-45 tons; the juvenile is 4 meters long and weighs 500 kilograms at birth. Compared with the body, the sperm whale's head is disproportionately heavy and large, with the largest brain in the animal kingdom, while the tail is light and small, which makes the sperm whale's body look like a big tadpole. The head of an adult male whale is particularly prominent, usually accounting for four to one-third of the total length of the body, and the appearance is roughly square. Its nostrils are located on both sides of the left front of the top of this huge rectangular body. The abnormal thing is that although the sperm whale has two nostrils, only the left nostril is unobstructed and used for breathing, while the right nostril is naturally blocked, which causes the sperm whale to always lean to the right when it surfaces to breathe, and the water mist column sprays to the left front