Blue Whales

Blue Whales

Marine Wildlife
  • Tuesday, 14 July 2015
  • Jaydee Media

The blue whale (Balaenoptera musculus) is the largest baleen whale and the largest animal that ever lived on Earth

Blue whales (Balaenoptera musculus) are baleen whales (Suborder Mysticeti). They are one of 76 cetacean species, and are marine mammals.

BlueWhaleNOAA Photo Library

Facts about blue whales

General Description:

  • The Blue Whale is the largest creature ever to have lived on earth.
  • Though we can’t hear them, blue whales are one of the loudest animals on the planet, communicating with each other using a series of low frequency pulses, groans, and moans. It is thought that in good conditions blue whales can hear each over distances of up to 1,600km.  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.
  • Blue whales occasionally swim in small pods but usually alone or in pairs.
  • 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.    
  • Amazingly, however, this giant of the ocean feeds on some of the smallest marine life – tiny shrimplike animals called krill. A single adult blue whale can consume 3,6000kg of krill a day.  These enormous mammals eat tiny organisms, like plankton and krill, which they sieve through baleen.
  • They mainly catch their food by diving, and descend to depths of approximately 500m.
  • 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.
  • 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 have a life expectancy of 35-40 years.



  • 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.
  • Their tongues alone can weigh as much as an elephant. Their hearts, as much as a car.

General Info:

  • The whale’s mouth has a fascinating row of plates fringed with bristles to help it filter its’ main source of food – Plankton from the water.  There is what looks like a moustache of long bristles on the end of each plate to help it hold the minute prey.  With each mouthful, the whale can hold up to 5,000kg of water and plankton.  Having forced the water out of its mouth, the whale licks these bristles with its fleshy tongue.
  • Although the blue whale is a deep-water hunter, as a mammal, it must come to the surface of the sea to breathe.  When it surfaces, it exhales air out of a blowhole in a cloud of pressurized vapour that rises vertically above the water for up to 9m.
  • They are thought to form close attachments.
    In spite of their bulk, these graceful swimmers cruise the ocean at over 8km/h, and can reach speeds of over 30km/h.

Reproduction and Calfs:

  • 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).
  • The calf is suckled in the water, drinking more than 600 litres {50-200 pounds (23-90 kg)}of milk each day and gaining about 90kg every day for its first year.
  • 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.
  • Blue whales have few predators but are known to fall victim to attacks by sharks and killer whales, and many are injured or die each year from impacts with large ships.
  • It is thought that whales feel emotions.
  • Intensive hunting in the 1900s by whalers seeking whale oil drove them to the brink of extinction. Hundreds of thousands of whales were killed. The 1966 International Whaling Commission finally gave them protection, although they have only recovered slightly since then. Blue whales are currently classified as endangered on the World Conservation Union (IUCN) Red List. It is estimated that only10,000-25,000 blue whales now swim the world's oceans.


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