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.

Animal Facts

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

What Can I Do?: Visit The Whale and Dolphin Conservation Society and The Ocean Conservancy for information on how you can help.