Balaenoptera musculus

• The blue whale can reach speeds of up to 37 km/h over short distances, and in exceptional cases up to 48 km/h. It cannot maintain this speed for long, as it is too stressful for its body.
• A blue whale embryo reaches a length of more than half a meter by the end of the first month. By the end of the second month, its length exceeds 80 cm.
• The name "blue whale" is related to the Latin word "musculus," meaning "muscular." It is believed that Linnaeus meant this, not "mouse.
• Blue whale calls can be heard up to 1600 km away. Scientists recorded a blue whale call with an intensity of 189 decibels at a distance of 200 km, but other researchers reported detecting calls from blue whales at distances of 400 and even 1600 km.
• The lifespan of the blue whale is not fully known, but it is estimated to be 80–110 years. The oldest known individual was 110 years old.
• The blue whale's heart is the largest in the world, weighing close to a ton. However, the heart of the baleen whale is relatively much smaller than that of toothed whales.
• The blue whale is the largest whale and the heaviest animal ever to have existed on Earth. Its weight can exceed 150 tons.
• Blue whales produce infrasound calls with an intensity almost no lower than 60 decibels. At a frequency of about 1 Hz, their calls reach the highest intensity. These signals last 8–18 seconds.
• Blue whale mother's milk contains up to 50 % fat and protein. Fat and protein together make up to 50 % by mass.
• The blue whale's lower jaw is the widest relative to the head width among other baleen whales. It curves outward and extends forward beyond the tip of the snout by 15–30 cm.
• The blue whale's dorsal fin is the smallest among baleen whales. Its length is about 1 % of body length, maximum 35 cm. The fin edges, especially the rear ones, are covered with scratches forming an individual pattern.
• The blue whale's lower jaw can weigh so much that it is difficult for the whale to close its mouth. Measurements of a 150-ton blue whale 29 m long showed its mouth could hold 32.6 m³ of water.
• Fat accumulated by the blue whale during intense feeding allows it to go almost without food for several months. Its large body mass helps it consume a lot of food when it is available in high concentration.
• The blue whale strongly bends its body, lowering its head, to dive deeply. The highest point at this time becomes the part of the back with the fin, when the head and front part of the back are already underwater.
• The throat ridges of the blue whale allow the mouth to stretch very strongly, and the movable joint of the lower jaw enhances this property. The throat ridges and the lower jaw bone joint ensure a sharp increase in mouth volume.
• The blue whale's blubber layer strongly slows down body cooling. Due to high thermal insulation, the body of a killed whale quickly starts to heat up from inside, and after 20 hours the meat was already boiled.
• A blue whale calf is born 6–8.8 m long and weighs 2–3 t. In the vast majority of cases, only one calf is born, usually weighing 2700–3600 kg.
• Blue whales can exchange signals up to 33 km away. Studies conducted near Antarctica showed that this distance is achieved using infrasound signals.
• A blue whale exhales a water spout up to 10 m high. The spout has the shape of a narrow cone or column that widens upward.
• The fat content of the blue whale varies from 1.39 % in a lean male to 8 % in a severely obese pregnant female. Fat content is higher in females, especially if they are pregnant.
• Fat in the blue whale accounts for up to 31 t of its total body mass of 108.6 t. The thickness of the fat layer reaches 30 cm, more than in other baleen whales.
• The blue whale has well-developed hearing and touch. The blue whale’s tongue weighs up to 4 t.
• The blue whale has longitudinal stripes on the lower part of the head and on the belly, which help the throat stretch greatly when swallowing water with food. The blue whale usually has 55–68 and even 80–90 such stripes.
• A blue whale can stay underwater for up to 50 minutes when pursued by whalers. A blue whale being chased by whalers dives much longer than usual.
• A blue whale calf gains up to 23 tons in mass over 7 months. It consumes up to 90 liters of milk per day and gains an average of 44 kg in mass.
• A single large baleen plate in a blue whale can weigh up to 90 kg, more than in other baleen whales. However, it is less than in the bowhead whale.
• Toxic chemicals such as polychlorinated biphenyls accumulate in the blubber of blue whales. These substances enter the ocean and are passed to calves while still in the womb of pregnant females.
• Female blue whales migrate north in winter to protect calves from cold, despite food availability in Antarctica. Newborns have underdeveloped blubber, making them especially vulnerable.
• Female blue whales develop multiple embryos, and extra ones are reabsorbed at later stages of pregnancy. The maximum recorded number of embryos in a blue whale female is 7.
• Blue whale pairs maintain long-term bonds; males do not leave females under any circumstances. This is known to occur in adult individuals that stay together for long periods.
• Blue whale meat, like that of other baleen whales, is edible, unlike the meat of toothed whales, such as sperm whales, which has a strong unpleasant odor. Meat of young blue whales is soft and tender, pinkish-red in color.
• Each side of the upper jaw of a blue whale has between 260 and 400 plates, totaling 540–790 plates, sometimes over 800. It has the most plates of any whale, with a record of 800.
• The blue whale consumes up to 8 tons of krill daily, which includes up to 40 million individual crustaceans. It requires about 3–4 % of its body weight in food per day.
• Young blue whales breathe much more frequently than adults — after surfacing from a deep dive, an 18-meter whale makes 5–10 breaths in 2 minutes, while a 22.5-meter adult does so 7–11 times in 12.5 minutes.
• After a long and deep dive, the blue whale makes a series of 6–15 short surfacings and shallow dives. Each surfacing takes 6–7 seconds, and each shallow dive takes 15–40 seconds.
• The fringes on the blue whale’s baleen plates are quite rough and rigid, adapted for feeding on large crustaceans. Smooth whales, which feed on small planktonic crustaceans, have fine and elastic fringes.
• The blue whale gives birth to twins in 1 out of 100 cases. Knowledge of twin births became known relatively recently.
• The blue whale did not hunt for centuries, but its size could bring whalers significant profit. The blue whale’s size has always attracted whalers’ attention.
• An injured blue whale posed a serious threat to whaling ships, which in displacement were comparable to the whale. Ships weighed 150–300 tons, making them roughly the same size as the whale itself.
• The volume of the blue whale’s lungs is about 2.5 % of its body weight. This is three times less than in humans, where it equals 7.1 %.
• In the northern part of the Pacific Ocean, there may be up to 5 blue whale populations. American cetologists suggest that more than one population exists there.
• The increase in blue whale reproduction may be linked to the rise in krill quantity. This happened due to the decrease in large whales that ate krill.
• The blue whale's stomach can hold up to 1.5 tons of food. A tightly filled blue whale stomach can hold up to 1 ton of food and even up to 1.5 tons.
• The breathing frequency of the blue whale depends on age and diving depth. Non-diving young whales breathe 2–4 times per minute, while adults breathe 0.7–2 times per minute.
• The blue whale usually lives alone, unlike other cetaceans. It does not form groups, preferring solitary existence, although it sometimes appears in groups of 2–3 individuals.
• The blue whale is a typical planktivore, and its diet mainly consists of small crustaceans from the order Euphausiacea, not exceeding 6 cm in length. These crustaceans form large aggregations known as krill.
• Pygmy blue whales are more heavily infested with barnacles than other whales, both on their body and on their baleen plates. This occurs much more strongly than in other baleen whales.