Science, Tech, Math › Animals & Nature Blue Whale Facts Photos and information about the world's largest animal Share Flipboard Email Print NOAA Photo Library / Wikimedia Commons / Public Domain Animals & Nature Marine Life Marine Life Profiles Marine Habitat Profiles Sharks Key Terms Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Forestry Dinosaurs Evolution View More By Jennifer Kennedy Marine Science Expert M.S., Resource Administration and Management, University of New Hampshire B.S., Natural Resources, Cornell University Jennifer Kennedy, M.S., is an environmental educator specializing in marine life. She serves as the executive director of the Blue Ocean Society for Marine Conservation. our editorial process Jennifer Kennedy Updated January 29, 2020 The blue whale is the largest animal on Earth. Learn how big these whales get and more facts about these huge marine mammals. Blue Whales Are Mammals Doug Perrine / Photolibrary / Getty Images Blue whales are mammals. We are mammals, too, so both humans and blue whales are endothermic (commonly called "warm-blooded"), give birth to live young and nurse their young. Whales even have hair. Because blue whales are mammals, they breathe air through lungs, just like we do. When blue whales exhale, the air rises more than 20 feet and can be seen from quite a distance. This is called the whale's blow or spout. Blue Whales Are Cetaceans Dan Shapiro / NOAA Photo Library / Wikimedia Commons / CC BY 2.0 All whales, including blue whales, are cetaceans. The word cetacean comes from the Latin word cetus, which means "a large sea animal," and the Greek word ketos, which means "sea monster." Cetaceans propel themselves but undulating their tail up and down. They have blubber to help insulate their bodies. They also have excellent hearing, and adaptations for surviving in deep water, including collapsible rib cages, flexible skeletons, and a high tolerance for carbon dioxide in their blood. Blue Whales Are the Largest Animals on Earth NMFS Northeast Fisheries Science Center (NOAA) / Wikimedia Commons / Public Domain Blue whales are the largest animal on Earth today and are thought to be the largest animal that has ever lived on Earth. Swimming in this ocean right now, there are blue whales who can grow to more than 90 feet in length and over 200 tons (400,000 lbs) in weight. Imagine a creature the size of 2 1/2 school buses laid end-to-end and you'll get a sense of the size of the blue whale. The maximum weight of one blue whale is the same weight as about 40 African elephants. A blue whale's heart alone is about the size of a small car and weighs about 1,000 pounds. Their mandibles are the largest single bones on Earth. Blue Whales Eat Some of the Smallest Organisms on Earth Sophie Webb / NOAA / Wikimedia Commons / CC0 1.0 Blue whales eat krill, which average about 2 inches in length. They also eat other small organisms, such as copepods. Blue whales can consume 4 tons of prey per day. They can eat huge amounts of prey at once thanks to their baleen - 500-800 fringed plates made of keratin that allow the whale to gulp their food, but filter seawater out. Blue whales are part of the group of cetaceans called the rorquals, which means they are related to fin whales, humpback whales, sei whales, and minke whales. Rorquals have grooves (the blue whale has 55-88 of these grooves) that run from their chin to behind their flippers. These grooves allow the rorquals to expand their throat while feeding to accommodate huge amounts of prey and seawater before the water is filtered back into the ocean via the whale's baleen. A Blue Whale's Tongue Weighs About 4 Tons Dr. Mirko Junge / Wikimedia Commons / CC BY-SA 4.0 Their tongue is about 18 feet long and can weigh up to 8,000 pounds (the weight of an adult female African elephant). A 2010 study estimated that when feeding, a blue whale's mouth opens so wide, and is so large, that another blue whale could swim into it. Blue Whale Calves Are 25 Feet Long When Born CoreyFord / Getty Images Blue whales give birth to a single calf, every 2-3 years after a gestation period of 10-11 months. The calf is about 20-25 feet long and weighs about 6,000 pounds at birth. Blue Whale Calves Gain 100-200 Pounds Per Day While Nursing tane-mahuta / Getty Images Blue whale calves nurse for about 7 months. During this time, they drink about 100 gallons of milk and gain 100-200 pounds per day. When they are weaned at 7 months, they are about 50 feet long. Blue Whales Are One of he Loudest Animals in the World NOAA / Wikimedia Commons / Public Domain A blue whale's sound repertoire includes pulses, buzzes, and rasps. Their sounds are likely used for communication and navigation. They have very loud voices - their sounds can be over 180 decibels (louder than a jet engine) and at 15-40 Hz, are usually below our hearing range. Like humpback whales, male blue whales sing songs. Blue Whales May Live Over 100 Years Patricia Curcio / Wikimedia Commons / CC BY-SA 3.0 We don't know the true life span of blue whales, but the average life span is estimated around 80-90 years. A way to tell a whale's age is to look at growth layers in their earplug. The oldest whale estimated using this method was 110 years. Blue Whales Were Hunted Nearly to Extinction Dutch National Archives / Wikimedia Commons / CC0 1.0 Blue whales don't have many natural predators, although they may be attacked by sharks and orcas. Their main enemy in the 1800-1900s was humans, who killed 29,410 blue whales from 1930-31 alone. It is estimated that there were more than 200,000 blue whales worldwide before whaling, and now there are about 5,000. References and Further Reading American Cetacean Society. Blue Whale.Discovery of Sound in the Sea (DOSITS). Blue Whale.Gill, Victoria. Blue Whale's Gigantic Mouthful Measured. BBC News. Dec. 9, 2010.National Geographic. Blue Whale.NOAA Fisheries: Office of Protected Resources. Blue Whale (Balaenoptera musculus)Seymour Marine Discovery Center at Long Marine Laboratory. Ms. Blue's Measurements.Stafford, K. Blue Whale (B. musculus). Society for Marine Mammalogy.