The Latin scientific name of whales is derived from the Greek word "sea monster", which shows the awe that the ancients had for these behemoths that inhabited the ocean. In fact, the body shapes of cetaceans vary greatly. Small ones are only about 1 meter in length, while the largest ones can reach more than 30 meters. Most of them live in the ocean, and only a few species inhabit freshwater environments. Their body shapes are very similar to fish. They are all streamlined and suitable for swimming, so they are commonly called whales. However, this similarity is just a biological phenomenon. An evolutionary convergence phenomenon. Because cetaceans have the same characteristics as viviparous, lactating, thermostatic and pulmonary breathing, they are exactly the same as fish, so they are classified as mammals. The unique characteristic of cetaceans is that their body temperature is constant, about 35.5°C. The skin is bare, with no body hair, only a few bristles on the snout, and no sweat glands or sebaceous glands. Subcutaneous fat is thick and helps maintain body temperature and reduce the body's weight in water. The skull is well developed, but the brain is small, the face is large, and the forehead bone and maxilla are significantly extended, forming a very long snout. The neck is not obvious, the cervical vertebrae are healing, and the head is directly connected to the torso. The forelimbs are fin-shaped, the toes are not separated, and there are no claws. The joints of the elbow and wrist cannot move flexibly, so they are suitable for swimming in the water. The hind limbs have degenerated, but there are still remnants of the pelvis and femur, which are in the form of remaining bone fragments. The tail degenerates into a fin, and the skin at the end expands horizontally from left to right to form a pair of large tail lobes, but they are not supported by bones. The vertebrae gradually taper off the long and narrow tail trunk, and finally disappear before entering the tail fin. The tail fin is different from that of fish. It can move up and down and is the main organ for swimming. Some species also have dorsal fins for balance. Their bones have sponge-like tissue and there is more fat in the body cavity, which can increase the size of the body, reduce the specific gravity of the body, and increase buoyancy.
Their eyes are small, without tear glands and nictitating membranes, and their vision is poor. There is no external ear shell, and the external auditory canal is very thin, but the hearing is very sensitive, and it can feel ultrasonic waves, and rely on echolocation to find food, contact companions, or escape enemies. There are 1-2 external nostrils, located on the top of the head, commonly known as the blowholes. Generally, the farther the nostrils are located, the higher the degree of evolution. Breathe with the lungs. There are two lungs on the left and right. There are many capillaries in them. They are elastic and can help the circulation of oxygen and adapt to the gas exchange on the water surface. You need to surface for ventilation every once in a while. Can dive for longer periods of time. There are 10 to 20 pairs of ribs. The stomach is divided into 4 chambers. The kidneys are mostly tumor-like.
The ancestors of cetaceans were originally animals that walked on land on all fours. They may have been insectivores or carnivores that mainly lived in coastal areas. Later, they were attracted by fish and other food in the water. After a long period of time, they returned to the ocean from land and gradually adapted to ocean life. The earliest whales appeared around 55 million years ago; 36 million years ago in the middle Eocene Epoch, Eocetus, Eodontocetus, and Protocetus in the late Eocene Epoch. Compared with existing whales, their skulls were smaller. The nostrils are located in the front of the head and have not yet moved to the top of the head. The teeth are similar to those of ancient insectivores and carnodonts, with 44 or less teeth. The tooth shape and skull are also very similar, with only a few. They are different, but they already have a body shape similar to fish that is adapted to living in seawater.
The body shape of toothed whales varies greatly. The smallest species is only about 1 meter long, and the largest is more than 20 meters long. There are cone-shaped teeth in the mouth, but the shape and number of different types of teeth vary greatly. The least has only one single tooth, and the most has dozens of them. Some are hidden in the gums and are not exposed, so they are also carried out. One of the important basis for classification. There is only one external nostril, so it can only spray out a jet of water when breathing. The skull is asymmetrical from side to side. There are 5 fingers on the flippers. The sternum is larger. No collarbone. There is no cecum. They mainly feed on squid, fish, etc., and some can also prey on large animals such as seabirds, seals, and other whales. There are eight toothed whale families in the world, including freshwater dolphins, sperm whales, stegopods, narwhals, sharp-beaked dolphins, porpoises, dolphins and pilot whales, with about 34 genera. 72 species. Baleen whales are huge in size, with the smallest species being more than 6 meters long.
There are no teeth in the mouth, and only degenerated teeth can be seen during embryonic development. However, there are 150-400 horny whiskers arranged in a comb-like arrangement from the palate to the pharynx on the left and right sides of the maxilla. The color, shape and number of whiskers vary from species to species and are one of the important basis for classification. There are two external nostrils located on the top of the head, which can spray out two jets of water when breathing. The skull is very large, up to 1/3 of the body length in some species, and is symmetrical. Cervical vertebrae heal or separate. The sternum is small, only 1?/FONTgt; 2 pairs of ribs are connected to the sternum, and the thorax is incomplete. No collarbone. The flippers generally have 4 fingers. There is a cecum in the digestive tract. They mainly feed on small crustaceans such as krill, but some species also eat small schooling fish, as well as bottom-dwelling fish and shellfish. There are three families of baleen whales in the world: right whales, gray whales and fin whales, with approximately 6 genera and 11 species. Due to their great economic value, whales have been hunted by humans since ancient times. However, in the past, due to backward hunting methods, the hunting volume was small, which was not enough to affect the number of whales. In modern times, people switched to using ships and artillery to hunt whales, which greatly increased their lethality, causing the number of whales to plummet and many species to be on the verge of extinction. Now that countries around the world have imposed strict limits on the number of whales caught each year, whaling has gradually become less of a major concern for scientists who monitor the numbers and survival of whales. However, throughout the world, unprecedented marine pollution caused by human economic development has posed a great threat to cetaceans. The degree of threat is far greater than hunting. In addition, the rapid development of industrial fishing has also greatly affected whales. It affects the food source of marine mammals such as whales and is another major factor affecting their survival. In the past, people always imagined the ocean as a symbol of a vast free world and a place for adventurous activities. Therefore, while unscrupulously plundering ocean resources, not only due to the large amount of ocean noise generated by the shipping industry and the large amount of ballast water discharged every year , and a large amount of garbage is dumped into the ocean. About 100,000 chemicals also reach the ocean through sewage discharge and air. Organic chlorides that are difficult to decompose increase the content of organic matter in the ocean, making ocean pollution more and more serious, and brought serious consequences. Modern scientific research results show that the ocean is a giant container for storing waste carbon dioxide. The hot and cold ocean current system has a great impact on the earth's climate. In the deep sea, which has been rarely studied, there are many unknown animals and plants that are beneficial to human beings. These include many potential sources of food and medicine for humans and are of great value. Increasing levels of ocean pollution will destroy these precious resources. Due to the destruction of the ozone layer, the population density of krill living in the waters around Antarctica has decreased sharply. The number of krill per 1,000 cubic meters of seawater has dropped sharply from 177.8 before 1982 to 1983 to 1984 to 1985. 41.2 tail. Krill is a kind of crustacean in the ocean. It is an important food for marine fish, whales and other marine mammals. It plays an extremely important position in the marine biological chain, and it is the largest protein resource left on the earth. It also received great attention from people. Since marine mammals such as whales are at the end of the food chain, marine pollution, especially heavy metal pollution and other irritating substances, has seriously weakened their immune systems, making them extremely vulnerable to viruses and bacteria. my country is very rich in cetacean resources. So far, 9 families, 26 genera, and 38 species have been discovered in our waters. Among them, there are blue whales with a body length of more than 30 meters and finless porpoises with a body length of only about 1 meter. , especially the specialty freshwater cetacean - the white-tip dolphin, which is a rare species among cetaceans. Except for two species of cetaceans in my country, the white-tip dolphin and the Chinese white dolphin, which are listed as national Level I protected animals, all other species are listed as Level II protected animals. The largest on earth - blue whale
Size
7 meters at birth and 24-27 meters as adults; baby blue whales are 6 meters at birth and 21-22 meters as adults.
Weight
The birth weight is about 2.5 tons, and the adult weight is 100-120 tons.
Morphological characteristics
It has a large body, blue-gray body color, mottled body surface, small, short and blunt dorsal fin, located toward the back, and a broad, flat, U-shaped head. The fumarole front is huge, the tail trunk is very thick, and the jet reaches 9 meters. When diving, the tail fin may be displayed, the body is streamlined, there are many wrinkles under the throat, the baleen plate is medium-long, and the upper jaw is horizontal when viewed from the side.
Behavior and Natural History
There are three different subspecies, the intermediate blue whale that lives in the southern hemisphere, the smaller blue whale that lives in the northern hemisphere, and the smaller blue whale that lives in the southern hemisphere. A tropical subspecies of the little blue whale. Adult whales rarely jump out of the water. They usually jump out at an elevation angle of 45 degrees, and then fall back on the side of their abdomen. In some areas, feeding activity seems to occur in the evening or early morning, with group sizes of 1-2, with sometimes larger groups in good feeding areas.
Distribution
Mainly in cold waters and oceans, and at the edges of continental shelves. Extant
About 6,000-14,000.
Habits
Blue whales are also called "razor whales". Mammalia, Cetacea, Cyprinidae. Widely distributed, found in oceans from the Arctic to Antarctica.
The blue whale is currently the largest animal on the earth. An adult blue whale can grow to more than twice the weight of the largest dinosaur that ever lived on the earth, the Gibosaurus, and 30 times the weight of the African bull elephant. About times. The blue whale is a real sea monster, with an average length of about 26 meters, the highest record is 33.5 meters, and an average weight of 150 tons. Such a giant beast needs a lot of food. An adult blue whale consumes about 1 million calories a day, which is equivalent to 1 ton of krill. Krill is its bulk food. Blue whales swim into the shallows and swallow mouthfuls of water and krill. The krill are filtered out by the tongue, which acts as a piston and forces the water out through large sieve-like structures of baleen suspended on either side of the upper jaw. A blue whale's tongue is more than 3 meters thick and weighs more than an elephant.
Blue whales are mammals that breathe with lungs, so they need to come out of the water to breathe every 10-15 minutes. When a blue whale emerges from the water, it expels carbon dioxide from its lungs through its nostrils before inhaling. The hot and powerful carbon dioxide exhaust gas expelled from the nostrils, accompanied by loud screams, also swept the nearby seawater out of the water, reaching a height of about 10 meters, and a spectacular white fog column appeared on the sea.
Blue whales once roamed all the world's oceans. According to statistics, there were 250,000 of these giant beasts in the Southern Ocean alone. But in recent years, the ruthless whaling industry has reduced the number of blue whales to less than 1 of the total. Determining the number of blue whales is difficult, but current estimates range from a few hundred to 11,000 in the Antarctic. Whether this number is correct or not, it is dangerously low compared to what it once was. Although whaling has been restricted for the past 50 years, with a ban imposed in 1967, commercial hunting of blue whales continues under the guise of scientific research.
Blue whales migrate long distances. In summer, they live in polar waters and feed on large amounts of krill near the edges of ice floes. , especially addicted to eating krill. When the blue whale eats, it opens its huge mouth to let seawater and zooplankton pour in, like a confluence of rivers. Then it closes its mouth, and the seawater is discharged from the slits in its baleen, and the filtered small animals can be swallowed. Enter the belly. When winter comes, they migrate to warm equatorial waters, traveling thousands of kilometers. It is reported that a blue whale travels more than 3,000 kilometers in only 47 days. Such a long journey takes them far away from their feeding base, and they do not eat for up to 4 months. Live off your savings.
Blue whales that are old enough to swim the world's oceans alone or in pairs can live up to 120 years old. Despite their solitary lifestyle, they have advanced methods of communicating over long distances, producing a low-frequency, high-intensity sound. The recorded sound frequency reaches 180 decibels, which is the largest known noise produced by motion, exceeding the noise produced by a jet aircraft in flight. The sound lasts for 30 seconds and can be heard by other blue whales up to 1,610 kilometers away.
The blue whale is also a unique strongman in the animal world.
A blue whale moving at a speed of 28 kilometers per hour can generate 1,250 kilowatts of power, which is equivalent to the pulling force of a medium-sized locomotive. A blue whale once towed a 27-meter-long whaling speedboat for 8 and a half hours at an average speed of 9 kilometers per hour. At that time, the speedboat was going backwards at full power, but it was still being pulled forward by it. Traveled 74 kilometers.
Ventriloquist" - Beluga
Size
1.5-1.6 meters at birth, about 3-5 meters in adulthood
Weight
Birth weight is 80 kilograms, and adult weight is 0.4-1.5 tons. Morphological characteristics
The body color is very light, showing a unique white color, with a small head, a round forehead, and a slender back. The dorsal fin, beak is very short, and the lips are broad. It usually swims slowly, is very easy to approach, often peeks, and is not good at aerial stunts.
Behavior and natural history
On white waves and ice floes. It is not easy to recognize them in the sea. You must pay attention to the white objects that will appear, grow in size, shrink and then disappear. They spend most of their time on or near the sea surface, and occasionally move their heads in gentle undulating movements. It rises out of the water. On calm days, its puffing sound can still be heard hundreds of meters away. The size of the group is 5-20. In summer, hundreds or even thousands may gather near the river mouth.
Distribution
In seasonal ice-covered waters of the Arctic and sub-Arctic
Extant
50,000-70,000
Habits
Beluga whales are authentic summer travelers. Every July, thousands of beluga whales set out from the Arctic region to begin their summer journeys. They range from a few to tens of thousands. , swimming majestically toward the resort. They played leisurely and kept performing, and the usually deserted bays, estuaries, and deltas suddenly became extremely lively.
Beluga whales are a kingdom of whales. The best "ventriloquist" experts in the world, they can make hundreds of sounds, and the sounds they make are so varied that it is amazing to be able to listen to the singing voice of the beluga in person.
In order to understand the sounds of beluga whales, scientists conducted on-site underwater recordings at the beluga whale resort in the estuary delta. The results were beyond people's imagination. They actually heard the roar of beasts, the lowing of cows, and the grunting of pigs. The neighing of horses, the squeaking of birds, the screams of women, the moans of patients, the cries of babies... there are so many strange things. Belugas can also make the sound of hinges, bells, steamboats, etc.
Beluga whales keep "singing", which is actually to entertain themselves, and it is also a kind of communication between their companions. This is an important part of their summer vacation. The beluga whales were very excited when they entered the estuary. Although they have traveled a long distance, they don't seem to feel tired at all. In addition to constantly "communicating" with different singing voices, they also use their wide tail lobes to play in the water, and their bodies are half exposed out of the water. It is so beautiful that tourists rush to snap this precious shot. Beluga whales can also use various "toys" to play with. They can use a piece of wood, a piece of seaweed, or a stone as their game object. The long seaweed swims for a while, then floats up, and keeps making cheerful sounds in its mouth. Sometimes they are fascinated by a stone the size of a basin. What's even more amazing is that they will put rocks on their heads and perform on the water like acrobats.
Beluga whales are not only elegant, but also very clean. When many beluga whales first swam to the estuary delta, they had many parasites attached to their bodies and looked very dirty in appearance and color. They themselves seemed extremely uncomfortable. At this time, they dived into the water one after another, rolled around under the river, and kept turning over. There are also some beluga whales that rub themselves on the gravel or gravel in the delta and shallow beaches. They turned around like this every day, for several hours a day. A few days later, all the old skin on the beluga whale shed off and was replaced with clean and beautiful new white skin. The body color took on a new look and was extremely beautiful.
Beluga whales are social animals, and most of their vacation spots are concentrated in northern latitudes.
However, some naughty beluga whales seem to have a tendency to wander independently from the group. Sometimes a beluga goes south alone and swims hundreds of kilometers gracefully, revealing its majestic appearance at the mouth of the Heilongjiang River or the Estuary of the Forth River in Scotland, bringing unexpected surprises to people. Sometimes a white whale wanders along the Rheinland Road, visiting Cologne and then Bonn, staying for more than a month. Tens of thousands of people watch it from boats and on the shore, which becomes a sensational local news. The blue whale is one of the seven species in the genus Aegocetus. But DNA sequencing analysis shows that blue whales are genetically closer to humpback whales and gray whales than other species in their genus. There are at least 11 documented records of adult offspring of blue whale/fin whale hybrids. Aronson and Gelberg (1983) suggested that the difference between blue whales and fin whales is similar to the difference between humans and gorillas. It is generally believed that the cetaceans separated from other families of the baleen whale suborder as early as the mid-Oligocene. But it is unknown when members of these families separated from each other.
The species name musculus comes from Latin and means "strong", but it can also be understood as "little mouse". Linnaeus, who named the species in his seminal work of 1758, may have known this and used the ironic pun humorously. Blue whales are also known by other common names, such as Sulfur-bottom, Sibbald's Rorqual, Great Blue Whale and Great Northern Rorqual, in recent decades. These names are gradually forgotten by people. The blue whale is the largest type of baleen whale. The longest one is a female whale caught in Antarctic waters from 1904 to 1920. It is 33.58m long and weighs 170 tons. The female is larger than the male, and the southern blue whale is larger than the northern blue whale. Viewed from above, the muzzle is broad and flat. The dorsal fin is small, about 0.4m high, located in the rear 1/4 of the body. The flippers are smaller, accounting for 15% of the body length. The width of the caudal fin is 1/3 to 1/4 of the body length, and the trailing edge is linear. There are 55 to 88 sting grooves, the longest of which reaches the umbilicus. There are 270 to 395 whisker plates on each side. The back of the body is dark gray-blue, the belly is slightly lighter, and the mouth and whiskers are black.
Blue whales are different from other species of whales. While other species appear short and stocky, blue whales have long vertebrae-like bodies that look like they are elongated. The head is flat and U-shaped, with obvious ridge-shaped protrusions from the upper lip to the blowhole on the back. The baleen plates are densely packed at the front of the mouth. About 300 baleen plates (about 1 meter long) hang on the upper jaw, about half a meter deep into the mouth. 60-90 grooves (called ventral folds) run along the throat parallel to the body. These folds are used to expel seawater after swallowing large quantities (see the section "Predation").
The blue whale’s dorsal fin is small and can only be seen briefly during the dive. The shape of the dorsal fin varies among individuals; some have just a barely visible ridge, while others have a striking, sickle-shaped fin. The dorsal fin is approximately three-quarters of the body length. When surfacing to breathe, blue whales lift their shoulders and blowhole areas out of the water to a much greater degree than other large whales, such as fin whales and pomfret whales. This often serves as a useful clue for identifying marine species. When breathing, if the sea is calm, the blue whale sprays a spectacular vertical water column (up to 12 meters, usually 9 meters) that can be seen thousands of meters away. The blue whale's lung capacity is 5,000 liters.
The blue whale’s flippers are 3-4 meters long. The upper part is gray and the narrow edge is white. All white underneath. The head and tail fin are generally gray. But the back and sometimes the flippers are usually variegated. The degree of variegation varies significantly among individuals. Some may be entirely gray, while others may be dark blue, with a fair amount of gray and dark blue mixed together (grey-blue).
Blue whales can sprint up to 50km/h (30mph) when interacting with other whales, but their normal swimming speed is 20km/h (12mph). When eating, the speed drops to 5km/h (3 mph). Blue whales in the North Atlantic and North Pacific raise their tail fins when diving, but most other blue whales do not. Living habits:
Blue whales feed on plankton and their staple food is krill. A blue whale consumes 2 to 4 tons of food every day.
The swimming speed is 2~6km/h when feeding, 5~33km during migration, and the maximum speed per hour is 20~48km. Generally, 10 to 20 small dives are followed by a deep dive. The interval between shallow dives is 12 to 20 seconds, and the deep dive can last for 10 to 30 minutes. The spray mist column is narrow and straight, 6 to 12 meters high. Blue whales reach sexual maturity at about 10 years old. Northern blue whales give birth and mate in late autumn and early winter. In the southern hemisphere, they mate in the southern winter, with July being the peak season. The breeding season differs between the northern and southern hemispheres by half a year. During the gestation period of 10 to 11 months, the calf is 6 to 7 meters long and weighs about 6 tons. The lactation period lasts for half a year, and the weaning length can reach 16m. Estimates of the maximum age range from 30 years to 80 to 90 years. It is distributed worldwide, with the largest concentration in Antarctic waters, mainly in temperate and frigid waters with water temperatures of 5 to 20°C. A few whales have visited the Yellow Sea and Taiwan waters. Blue whales are one of the most important economic species and have a lot of fat. International regulations use the oil production of blue whales as the conversion unit, that is, 1 blue whale = 2 fin whales = 2.5 humpback whales = 6 baleen whales. Since the beginning of modern whaling, blue whales have been hunted excessively. At its peak in 1930-31, nearly 30,000 blue whales were killed worldwide in one year. In 1966, the International Whaling Commission declared blue whales a protected object prohibited from hunting. Before development, there were at least more than 200,000 blue whales, and now it is estimated that there are up to 13,000. According to a statistical report published by the International Whaling Commission in 1989, there are currently only 200 to 453 blue whale survivors. This is based on eight years of surveys in the southern hemisphere and is already on the verge of extinction.