Blue Whale Facts: Size, Weight, Diet & More

The blue whale (Balaenoptera musculus) is the largest animal ever known to have lived on Earth, reaching lengths of up to 100 feet and weights of up to 200 tons. To put this in perspective, that's heavier than even the largest dinosaurs that ever lived, including the Argentinosaurus.

Physical Characteristics

Blue whales are truly giants of the ocean. Their heart alone can weigh as much as a small car (about 400 pounds), and their tongue can weigh as much as an elephant (around 2.7 tons). A blue whale's arteries are so large that a human child could theoretically swim through them. Their enormous size is supported by the buoyancy of water. On land, such a massive creature would collapse under its own weight.

Diet and Feeding

Despite their enormous size, blue whales feed primarily on tiny shrimp like creatures called krill, consuming up to 4 tons of them per day during feeding season. They are filter feeders, using baleen plates instead of teeth to strain krill from the water. During feeding season (typically 120 days), a blue whale can consume up to 40 million krill in a single day.

Communication and Vocalization

Blue whales are among the loudest animals on Earth. Their calls can reach 188 decibels (louder than a jet engine) and can be heard by other whales from hundreds of miles away. These low frequency sounds travel vast distances through the ocean, allowing blue whales to communicate across entire ocean basins. Scientists believe they use these calls to navigate, find food, and locate potential mates.

Migration and Habitat

Blue whales are found in all the world's oceans except the Arctic. They undertake long migrations between feeding grounds in polar waters during summer and breeding grounds in tropical or subtropical waters during winter. Some populations travel over 10,000 miles annually.

Reproduction

Female blue whales give birth to a single calf after a gestation period of 10 to 12 months. Newborn calves are already massive, measuring about 23 feet long and weighing around 3 tons. They gain approximately 200 pounds per day while nursing on their mother's extremely rich milk (35 to 50% fat content).

Conservation Status

Blue whales were hunted nearly to extinction during the 20th century whaling era. At their lowest point, fewer than 1,000 individuals remained. Today, thanks to international protection, the population has recovered to about 10,000 to 25,000, but they remain endangered. Threats include ship strikes, entanglement in fishing gear, ocean noise pollution, and climate change affecting krill populations.