The Blue Whale Is One of the Loudest Animals on Earth

The blue whale (Balaenoptera musculus) is the largest animal that has ever lived. Gerard Soury / Getty Images

Blue whales are the largest animals in the world. Despite their large size, blue whales manage to be fairly elusive, so there's a lot about them we don't know yet.

Here's what we do know about blue whale habitats, behaviors, lifespans and diets.

About the Blue Whale

The blue whale (Balaenoptera musculus) is a marine mammal and the largest animal that has ever lived. Blue whales are actually more gray than blue, but they appear blue underwater.

Blue Whale Anatomy

Blue whales weigh up to 330,000 pounds (149,686 kg) and are up to 110 feet (33.5 meters) long — that's longer than three school buses).

They are rorqual whales, a group of baleen whales with grooves in their throats that allow their mouths to expand so they can gulp large amounts of water.

Blue Whale Lifespan

Blue whales can live 80 to 90 years. The oldest blue whale on record was estimated to be 110 years old.

Like all marine mammals, blue whales give birth to live young. Female blue whales reach sexual maturity around 5 to 15 years, at which time they can start birthing the largest babies in the animal kingdom.

Blue Whale Diet

The blue whale's diet consists of krill, tiny crustaceans that they filter into their mouths through baleen plates. This filter-feeding makes the blue whale a baleen whale, a group that includes humpback whales and gray whales, among others.

Blue Whale Predators

Orca whales (killer whales) have been known to kill blue whales, even though orcas are only one-third the size of a blue whale.

Recent attacks could be a good thing: "As whales and large whales recover, we might see that these attacks become more common as that becomes a more frequent and available prey again," John Calambokidis, a blue whale biologist at Cascadia Research, told NPR.

Blue Whale Habitat

Blue whales live in every ocean except the Arctic Ocean. There are five distinct populations of blue whales. These subspecies of blue whales include:

Antarctic blue whales (Balaenoptera musculus intermedia) are the largest subspecies. They live in the Antarctic Ocean (Southern Ocean). In the summer, Antarctic blue whales get close to the ice edge. When winter arrives, they migrate towards the eastern tropical Pacific.
Chilean blue whales are the latest subspecies of these large whales to be discovered and have not yet been named. They migrate between the southeastern Pacific and eastern tropical Pacific.
Northern blue whales (Balaenoptera musculus musculus) live in the Northern Hemisphere. In the North Atlantic Ocean, they range from the subtropical zone to the Greenland Sea. In the Pacific Ocean, their summer feeding grounds are off the West Coast of the United States; in the winter, they migrate to Central America and Mexico.
Northern Indian Ocean blue whales (Balaenoptera musculus indica) are found off the coast of India, Somalia and Sri Lanka and around the Maldives.
Pygmy blue whales (Balaenoptera musculus brevicauda) are the smallest subspecies and some do not consider them "true" blue whales. They live in the Southern Hemisphere near Australia, Madagascar and New Zealand.

Where Can I See a Blue Whale?

Popular whale-watching spots include:

The Azores in Portugal
The Channel Islands and Monterey Bay on the California Coast, U.S.
Loreto Marine Reserve in Baja California Sur, Mexico
Mirissa in Sri Lanka
Saguenay-St. Lawrence Marine Park in Quebec, Eastern Canada
Skjalfandi Bay in Iceland

Blue Whale Behavior

Blue whales live alone, in pairs or in small groups and generally migrate from summer feeding grounds in polar waters to warmer winter breeding grounds.

Blue whales are some of the loudest animals in the world; other whales can hear their calls from up to 1,000 miles (1,609 km) away, according to the National Oceanic and Atmospheric Administration (NOAA). Blue whale calls can reach 188 decibels.

Blue Whale Conservation Status

The blue whale is on the IUCN Red List of Threatened Species as an endangered species. IUCN estimates there are 5,000 to 15,000 blue whales left.

In the early 20th century, commercial whaling significantly impacted global blue whale populations. In 1964, the International Whaling Commission banned commercial whaling, granting the blue whale worldwide protection.

The biggest threats to blue whale recovery are entanglement in fishing gear, vessel strikes, pollution and climate change. To prevent ship strikes, the NOAA recommends boaters reduce their speed to 10 knots in areas with whale activity.