- Status: Endangered
- Known as: Blue Whale.
- Estimated numbers left in the wild: 10,000 to 25,000.
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The blue whale is a spectacular ocean creature, quite probably the heaviest animal to ever exist on Earth. Its weight of at least 170 tonnes put it well ahead of the largest dinosaurs, which likely weighed 90 tonnes or so.
Blue whales are 30 meters long, dwarfing human beings and even fairly large human vehicles such as buses. A blue whale can spout water and air up to 10 meters upwards from its blow-hole when it surfaces.
Blue whales are baleen whales, meaning that they filter seawater through huge, slatted plates in their mouth, known as baleen. Large amounts of water are taken in and then squeezed out forcefully through the gaps in the baleen by the whale’s tongue.
This allows these massive creatures to harvest vast numbers of tiny animals called krill, similar to shrimp, which make up most of their diet. One adult whale needs around 3.6 tonnes of krill each day. A blue whale’s mouth can hold 90 tonnes of water, and its tongue alone weighs 2.7 tonnes.
Since whales are mammals, young whales nurse from their mother’s milk before being weaned onto krill. A young whale consumes 400 liters of milk daily.
Blue whales can move to the nutrient-poor equatorial waters to breed because they can store huge amounts of energy in their vast body.
When krill is abundant, blue whales can eat ninety times the amount of energy they use up in the process of finding, catching, and processing their food. This extreme efficiency lets the lay down massive energy reserves for the stresses of reproduction.
Blue whales, like other whales, “sing,” producing subsonic and sonic noises for up to 30 seconds at a time. These sounds echo hauntingly through the sea for many kilometers; other blue whales can likely hear them 1,600 kilometers away, though their exact purpose is still unknown.
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Blue whales are found throughout the world’s oceans. Most are concentrated in specific areas today, including the North Atlantic, the eastern North Pacific, the Indian Ocean, and the Antarctic Ocean. Blue whales can only live in deep oceanic areas, preferring the cold regions where krill are abundant except in breeding season when they move closer to the equator.
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Threats: The blue whale was largely immune to human whalers for centuries, thanks to its size, strength, and speed. It was only the introduction of the harpoon gun in the 19th century that allowed the harvesting of this giant creature.
Over 300,000 were killed before the 1966 ban, with the Soviet Union continuing illegal whaling into the 1970s and Japan continuing to hunt whales for meat under cover of science.
Blue whales are no longer commercially hunted, but the road to recovery is long and difficult. Blue whales are struck accidentally by ships, which can easily injure or kill them, and maybe endangered further by alterations in krill populations due to global warming.
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Conservation efforts for the blue whale began in 1966 with the passage of the whaling ban on this species. Attempts to conserve, restore, and study these gigantic marine mammals continue to the current day. Both nonprofit organizations and various governments of the world are involved in efforts to foster the recovery of these huge but vulnerable creatures.
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The Hebridean Whale & Dolphin Trust
The Hebridean Whale & Dolphin Trust monitors marine mammals and their habitats off the coast of Scotland. They work to protect various species through outreach and educational programs.