There is an urgent need for information about blue whales

● Southern Blue Whale (B.M.? intermedia？ Burmeister, 187 1) Southern blue whales are distributed in the southern hemisphere; The female body length of southern blue whale is 23 ~ 24m, the male body length is 22m, and the mature body length is 26 ~ 27m and 24 ~ 25m respectively.

● Northern blue whale (B.M.? Muscle? Linnai, 1958) Northern blue whales are distributed in the North Atlantic and the North Pacific. The female body length of northern blue whale is 2 1 ~ 23m, the male sexual maturity is 20 ~ 2 1~23m, and the body length is 25 and 24m respectively.

● Little blue whale (B.m? brevicaukta？ Shiyuan, 1966) Little blue whales are distributed in the sub-Antarctic waters of the Indian Ocean and the Southeast Atlantic Ocean. When the female body length is 19m, the male body length is slightly less than 19m, and the female body length is 22 and 2 1m respectively.

The blue whale is one of the seven species of Zombie. However, DNA sequencing analysis shows that blue whales are closer to humpback whales and gray whales than other species in their genus. There are at least 1 1 articles about adult offspring of blue whale/fin whale hybridization. Aronson and Gerberg (1983) think that the difference between blue whales and fin whales is similar to that between humans and gorillas. It is generally believed that cetaceans were separated from other families of baleen suborder as early as the middle Oligocene. But I don't know when the members of these plates separated. ?

Phylogenetic Tree of Animals Related to Blue Whale Some authorities have divided this species into three subspecies: B? m？ Muscles, including populations in the North Atlantic and the North Pacific; B? m？ Intermediate population, including Southern Ocean population; B? m？ Brevikda? (also known as pygmy blue whale), including populations in the Indian Ocean and the South Pacific. An earlier authority listed the Indian Ocean population as a subspecies called B? m？ India. But unlike the other three subspecies, the name of the last subspecies does not appear on the Red List of Endangered Species. At present, these two classification methods are still questioned by some scientists; Genetic analysis shows that there are only two subspecies. ?

The species name musculus comes from Latin, which means "strong". But it can also be understood as "little mouse". Linnai completed this kind of naming in 1758. He may know this and then use this ironic pun humorously. Blue whales have other common names, such as sulfur whales and Sibbald whales? Rorqual (a close relative of killer whales), isn't it great? Blue? Whales (big blue whales) and? Great? North? Rorqual (Great Mako Northern Whale), these names have been gradually forgotten by people in recent decades. ?

size

The blue whale is the largest species among baleen whales. The oldest whale is a female whale caught in Antarctic waters between 1904 and 1920. It is 33.58 meters long and weighs 170 tons.

The blue whale is the largest animal that has ever lived on the earth. The largest known creature in the dinosaur era is the Mesozoic Argentinean dragon, which is estimated to be 90 tons (100 short tons). The weight of the largest blue whale is uncertain. Most of the data are taken from blue whales killed in Antarctic waters in the first half of the 20th century, and the data are measured by whalers who are not proficient in standard animal measurement methods. The longest whales recorded are two females, 33.6 meters (1 10 ft 3 in) and 33.3 meters (109 ft 3 in) respectively. However, the reliability of these measurements is controversial. Scientists at the National Marine Mammal Laboratory (NMML) measured the longest whale at 29.9 meters (98 feet), which is about the length of a Boeing 737 or three double-decker buses. ?

The head of the blue whale is so big that 50 people can stand on its tongue. Its heart is as big as a car. Babies can climb through its arteries, and newborn blue whale cubs are heavier than an adult elephant. In the first seven months of life, young whales drink 400 liters (100 US gallon) of breast milk every day. Young whales grow very fast, gaining 90 kilograms (200 pounds) every 24 hours. ?

? Because the blue whale is huge, we can't weigh it directly. Most blue whales are not weighed by the whole head, and whalers will cut them into appropriate sizes before weighing them. This way underestimates the weight of the blue whale, because it will lose blood and other body fluids. Even so, it is recorded that a whale 27 meters (88 feet 6 inches) long weighs 150- 170 tons (160- 190 short tons). NMML scientists believe that whales 30 meters (98 feet) long are estimated to exceed 180 tons (200 short tons). At present, the maximum weight of blue whale accurately measured by NMML scientists is 177 tons (197 short tons). ?

Physical characteristics:

Females are bigger than males, and southern blue whales are bigger than northern blue whales. Seen from above, the kiss is wide and flat. The dorsal fin is small, about 0.4m high, and 1/4 is at the back of the body. The flippers are small, accounting for 15% of the body length. The caudal fin is 1/3 to 1/4 in length, and the trailing edge is straight. There are 55 ~ 88 puncture grooves, the longest of which can reach the navel. 270 ~ 395 whiskers per side. The back of the body is dark gray-blue, the abdomen is slightly light, and the mouth must be black.

Blue whales are different from other kinds of whales. They are short and strong, while the vertebral body of blue whales is very long and looks like it has been elongated. The head is flat and U-shaped, and the pores from the upper lip to the back have obvious ridges. There are dense baleen plates at the front of the mouth, and about 300 baleen plates (about 1 m long) hang down from the upper jaw and pass through the mouth for about half a meter. 60-90 grooves (called abdominal folds) are parallel to the body along the throat. These folds are used to discharge seawater that has been swallowed in large quantities (see the section on "predation"). ?

The dorsal fin of the blue whale is so small that it can only be seen briefly when diving. The shape of dorsal fin varies from individual to individual; Some fins have only one protrusion just visible, while others are very eye-catching and sickle-shaped. The dorsal fin is located about three-quarters of the body length. When reaching the surface to breathe, blue whales lift their shoulders and stomata off the water to a greater extent than other large whales (such as fin whales and pomfret). This can usually be used as a useful clue to identify marine species. ? When breathing, if it is calm, the spectacular vertical water column (up to 12 m, usually 9 m) ejected by the blue whale can be seen thousands of meters away. The vital capacity of the blue whale is 5000 liters.

The fin foot of a blue whale is 3-4 meters long. The top is gray and the narrow side is white. The bottom is all white. The head and caudal fin are generally gray. But the back and sometimes flippers are usually variegated. The degree of variegated color varies from person to person, and the difference is obvious. Some may be gray all over, while others are dark blue. Gray and black are quite mixed together. ?

When blue whales interact with other whales, they can sprint at a speed of 50 km/h (30 mph), but usually swim at a speed of 20 km/h (12 mph). When eating, the speed drops to 5km/h(3? Miles per hour). Blue whales in the North Atlantic and the North Pacific lift their tail fins when diving, but most other blue whales don't. ?

Living habits:

Blue whales feed on plankton, mainly krill. A blue whale consumes 2 ~ 4t food every day. The swimming speed is 2 ~ 6 km/h when feeding, 5 ~ 33 km when migrating, and the maximum forced speed is 20 ~ 48 km per hour. General 10 ~ 20 dive is followed by a deep dive. Shallow dive interval 12 ~ 20 seconds, deep dive sustainable 10 ~ 30 minutes. The spray column is narrow and straight, with a height of 6 ~ 12m. The blue whale is sexually mature at the age of 10. Northern blue whales breed and mate in late autumn and early winter. The southern hemisphere mates in the south in winter, with the peak in July. The reproductive period between the northern and southern hemispheres is half a year apart. The gestation period is 10 ~ 1 1 month. The calf is 6 ~ 7 meters long and weighs about 6 tons. The lactation period is half a year, and the weaning time can reach 16m. The highest age is estimated to be between 30 and 80-90.

Predation:

Blue whales only prey on krill, and the plankton eaten by blue whales belong to different species according to different marine areas. In the North Atlantic, northern krill, Thysanoessa? Lacey? Thysanoessa？ Inermis and Thysanoessa? The long tail is the main food of blue whales. Krill in the North Pacific? Paphia? Thysanoessa？ inermis，？ Thysanoessa？ Long feet? Thysanoessa？ Spinifera and Nyctiphanes? Symplex is the main food; In Antarctica, Antarctic krill, krill? Lens loss? And then what? Euphausia？ Vallentni is the main food of blue whales. ?

? Blue whales usually prey on the densest krill they can find, which means that blue whales need to feed in deep water (100 meters or more) during the day and can only feed on the surface at night. The diving time of blue whales foraging is generally 10 minute. It is not unusual to dive for 20 minutes, and the longest diving time is 36 minutes (Sears, 1998). In the process of hunting, blue whales swallow a large group of krill at a time and a lot of seawater at the same time. Then squeeze the abdominal cavity and tongue, and squeeze the seawater out through the baleen. When the seawater in the mouth is completely discharged, the blue whale will swallow the remaining krill that cannot pass through the baleen whale board. ?

Life cycle:

Blue whales begin to mate after autumn and continue until the end of winter. We know nothing about mating behavior and breeding grounds. Females give birth every 2-3 years, usually in the early winter after 10- 12 months of pregnancy. This calf weighs about 2.5 tons and is about 7 meters long. About six months later, the calf was weaned and its length doubled. Blue whales generally reach sexual maturity at the age of 8- 10, when the males are at least 20 meters long (longer in the southern hemisphere). The female is relatively large and sexually mature at about 5 years old. At this time, the body length is about 2 1 m. ?

Scientists estimate that the life span of blue whales is at least 80 years; However, since individual records cannot be traced back to the whaling era, it will take many years to determine the exact life span of whales. The longest recorded research on a single individual was conducted in the Northeast Pacific for 34 years (Sears 1998 report). The natural enemy of the blue whale is the killer whale. Calambokidis et al. (1990) found that 25% of adult blue whales have scars left by killer whale attacks. However, there is no exact data on the death rate caused by the attack. ?

It is rare for a blue whale to run aground. Because of its special group structure, we have never heard of the stranding of blue whales. But when the grounding does happen, it will attract much attention. 1920, a blue whale ran aground on the beach of Lewis Island, Hebrides Island outside Scotland. It was hit on the head by a whaling ship, but the harpoon didn't explode. Like other animals, blue whales instinctively keep breathing at all costs. Stranding can keep it from being bored to death. Two whale bones standing on the roadside of Luis Island attracted a large number of tourists. ?

Vocal music:

The blue whale is the loudest animal in the world. Cummings and Thompson (197 1 year) and Richardson et al. (1995) said that the sound of the blue whale can reach 1 55-/kloc-0 at the sound source by measuring the reference pressure at the distance from the blue whale1meter. Even considering the different impedances and standard reference pressures of water and air, the equivalent range in air is still 89- 122 dB. In contrast, the sound of a pneumatic drill is about 100 decibel. But humans may not realize that the blue whale is the loudest animal. The fundamental frequency of all blue whale populations is 10-40 Hz, and the lowest frequency that humans can detect is 20 Hz. The sound duration of the blue whale is 10-30 seconds. According to records, the sound of blue whales off the coast of Sri Lanka repeatedly sings a four-note "song", which lasts for two minutes at a time, reminding people of the song of humpback whales. The researchers believe that because this phenomenon does not appear in other people, it may be B.M.? The Brevicauda subspecies is unique.