Blue whales are the biggest animals in the world, and the females are larger than the males. The longest female on record measured 110 feet (34 m); the heaviest weighed 190 tons.
All three subspecies travel in pods composed of thirty to fifty individuals.
These whales, as with other members of the family Balaenopteridae, filter some six to seven tons of krill at a time with their baleen plates, "gulping" water and krill, then closing the mouth and forcing the water back out through the baleen.
Blue whales were too big and too fast for whalers before the 1864 invention of the exploding-head harpoon.
That and the indiscriminate use of factory ships have led to the species' rapid decline. Now fewer than ten thousand remain.
Name: Blue Whale (Balaenoptera musculus)
Family: Balaenopteridae (Rorquals)
Range: All major oceans of world
Habitat: Open ocean
Diet: Krill, other planktonic species, and small fish
Total Length: 79 to 89 feet (24 to 27 m); historically much larger
Weight: 220,000 to 330,000 pounds (100,000 to 150,000 kg); historically much larger
Life Cycle: Mating depends on locale; gestation 300 to 330 days, one calf born
Description: Slate to grayish blue skin; mottled with lighter spots; belly has yellowish tinge; short dorsal fin; wide upper jaw; blunt rostrum; throat grooves from chin to beyond naval
Conservation Status: Endangered
Major Threat: Pollution; hunting
The blue whale is the largest animal that ever lived on Earth. It is also the loudest animal on Earth. These enormous mammals eat tiny organisms, like plankton and krill, which they sieve through baleen. They live in pods (small groups). These gray-blue whales have 2 blowholes and a 2-14 inch (5-30 cm) thick layer of blubber.
Blue whales grow to be about 80 feet (25 m) long on average, weighing about 120 tons (109 tonnes). The largest specimen found was a female 94 feet (29 m) long weighing more 174 tons (158 tonnes). The females are larger than males, as with all baleen whales. The largest of the blue whales (150 tons) has a heart that weighs about 1,000 pounds (450 kg) and has 14,000 pounds (6,400 kg) of blood circulating in its body. The heart is about the size of a Volkswagon bug car. A human could crawl through the aorta (a major blood vessel).
Blue whales are the loudest animals on Earth! Their call reaches levels up to 188 decibels. This low-frequency whistle can be heard for hundreds of miles. The blue whale is louder than a jet, which reaches only 140 decibels! Human shouting is 70 decibels; sounds over 120 decibels are painful to human ears.
SKIN, SHAPE AND FINS
The blue whale's skin is usually blue-gray with white-gray spots. The underbelly has brown, yellow, or gray specks. During the winter in cold waters, diatoms stick to the underbelly, giving it a yellow to silver- to sulfur-colored sheen; they are sometimes called "sulfur bottom."
They have a very small, falcate (sickle-shaped) dorsal fin that is located near the flukes (tail). Blue whales have long, thin flippers 8 feet long (2.4 m) and flukes that are 25 feet (7.6 m) wide.
DIET AND BALEEN
Blue whales (like all baleen whales) are seasonal feeders and carnivores that filter feed tiny crustaceans (krill, copepods, etc.), plankton, and small fish from the water. They are gulpers, filter feeders that alternatively swim then gulp a mouthful of plankton or fish - they lunge into dense groups of small sea organisms (krill or tiny fish) with an open mouth. 50 to 70 throat pleats allow the throat to expand a great deal, forming a gular pouch. The water is then forced through the baleen plates hanging from the upper jaw. The baleen catches the food, acting like a sieve.
The blue whale has about 320 pairs of black baleen plates with dark gray bristles in the blue whale's jaws. They are about 39 inches long (1 m), 21 inches wide (53 cm), and weigh 200 pounds (90 kg). The tongue weighs 4 tons (3.8 tonnes).
An average-sized blue whale will eat 2,000-9,000 pounds (900-4100 kg) of plankton each day during the summer feeding season in cold, arctic waters ( about 120 days).
Blue whale breeding occurs mostly in the winter to early spring while near the surface and in warm waters. The gestation period is about 11-12 months and the calf is born tail first (this is normal for cetaceans) and near the surface in warm, shallow waters. The newborn instinctively swims to the surface within 10 seconds for its first breath; it is helped by its mother, using her flippers. Within 30 minutes of its birth the baby whale can swim. The newborn calf is about 25 feet long (7.6 m) and weighs about 6-8 tons (5.4-7.3 tonnes). Twins are extremely rare (about 1% of births); there is almost always one calf. The baby is nurtured with its mother's fat-laden milk (it is 40-50% fat) and is weaned in about 7-8 months. Calves drink 50-200 pounds (23-90 kg) of milk each day. The mother and calf may stay together for a year or longer, until the calf is about 45 feet long (13 m). Blue whales reach maturity at 10-15 years.
Packs of killer whales (orcas) have been known to attack and kill young blue whales. Man also hunted blue whales until the International Whaling Commission declared them to be a protected species in 1966 because of a huge decrease in their population.
It is estimated that there are about 10,000-14,000 blue whales world-wide. Blue whales are an endangered species. These whales (and many other large whales) were over-hunted for many years, since their meat, oil, and other body parts are very valuable. Since whale hunting has decreased in the last few decades, their populations are starting to recover.
- Blue whales live individually or in very small pods (groups). They frequently swim in pairs.
- Blue whales can dive for up to an hour, going to a depth of 350 feet (105 m).
- Blue whales breathe air at the surface of the water through 2 blowholes located near the top of the head. They spout (breathe) about 1-4 times per minute at rest, and 5-12 times per minutes after a deep dive. Their blow is a single stream that rises 40-50 feet (12-15 m) above the surface of the water.
- Blue whales are very fast swimmers; they normally swim 3-20 mph (4.8-32 kph), but can go up to 24-30 mph (38-48 kph) in bursts when in danger. Feeding speeds are slower, about 1-4 mph (1.6-6.2 kph).
- Blue whales emit very loud, highly structured, repetitive low-frequency sounds that can travel for many miles underwater. They are probably the loudest animals alive, louder than a jet engine. These songs may be used for locating large masses of krill (tiny crustaceans that they eat) and for communicating with other blue whales, especially in order to attract and find mates
- Blue whales live at the surface of the ocean and are found in all the oceans of the world.
- Blue whales have a life expectancy of 35-40 years.