Science, Tech, Math › Animals & Nature The 20 Biggest Mammals, Ranked by Category The blue whale is the largest mammal that ever lived, including dinosaurs Share Flipboard Email Print The phlegmatic capybara, the world's biggest rodent. Wikimedia Commons Animals & Nature Mammals Amphibians Birds Habitat Profiles Reptiles Wildlife Conservation Insects Marine Life Forestry Dinosaurs Evolution View More By Bob Strauss Science Writer B.S., Cornell University Bob Strauss is a science writer and the author of several books, including "The Big Book of What, How and Why" and "A Field Guide to the Dinosaurs of North America." our editorial process Bob Strauss Updated September 17, 2018 Whales are really big, and a hippopotamus is roughly the same size as a rhinoceros. But do you know the biggest mammals by category? Here's a list of the 20 biggest mammals, in 20 categories, starting with the biggest whale and ending with the biggest shrew: 01 of 20 Biggest Whale: Blue Whale (200 Tons) The Blue Whale, the world's biggest whale. Wikimedia Commons At 100 feet long and 200 tons, not only is the blue whale the biggest mammal in the world, but it's also the largest vertebrate animal that has ever lived. Not even the largest dinosaurs approached it in bulk. Some titanosaurs were over 100 feet long, but they didn't weigh 200 tons. Fittingly, the blue whale is also the loudest animal on earth. This cetacean can vocalize at 180 decibels, enough to render most other animals deaf. 02 of 20 Biggest Elephant: African Elephant (7 Tons) The African Elephant, the world's biggest elephant. Wikimedia Commons The largest land-dwelling mammal on earth, at seven tons, the African elephant is smaller than the blue whale for good reason: The buoyancy of water helps to counteract the blue whale's weight, and elephants are terrestrial. One reason the African elephant has enormous ears is to help dissipate its internal body heat. A warm-blooded, seven-ton mammal generates a lot of calories. 03 of 20 Biggest Dolphin: Killer Whale (6 to 7 Tons) The Killer Whale, the world's biggest dolphin. Wikimedia Commons How can the biggest dolphin be a whale? Killer whales, also known as orcas, are classified as dolphins rather than whales. At six or seven tons, male orcas are bigger than the largest sharks, which means that killer whales, rather than great white sharks, are the atop predators of the oceans. Sharks have a more fearsome reputation because very few humans have been killed by killer whales. 04 of 20 Biggest Even-Toed Ungulate: Hippopotamus (5 tons) The Hippopotamus, the world's biggest even-toed ungulate. Wikimedia Commons Even-toed ungulates, or artiodactyls, are a widespread family of plant-eating mammals that includes deer, pigs, cows, and the biggest cleft-hoofed mammal, the common hippopotamus. The pygmy hippopotamus doesn't approach its cousin's five-ton heft. You could make a case for another even-toed creature, the giraffe, which is much taller than a hippo, but they weigh only two tons. 05 of 20 Biggest Odd-Toed Ungulate: White Rhinoceros (5 tons) The White Rhinoceros, the world's biggest even-toed ungulate. Wikimedia Commons Perissodactyls, or odd-toed ungulates, aren't as diverse as their even-toed cousins. This family consists of horses, zebras, and tapirs on the one hand and rhinoceroses on the other. The biggest perissodactyl is the white rhinoceros, which at five tons rivals Pleistocene rhinoceros ancestors such as the Elasmotherium. There are two types of white rhinos, the southern white rhinoceros and the northern white Rhinoceros; it's easy to figure in what part of Africa they reside. 06 of 20 Biggest Pinniped: Southern Elephant Seal (3 to 4 Tons) The Southern Elephant Seal, the world's biggest pinniped. Wikimedia Commons At up to four tons, not only is the southern elephant seal the biggest pinniped alive, but it's also the biggest terrestrial meat-eating mammal, outweighing the largest lions, tigers, and bears. Male southern elephant seals vastly outweigh females, which top out at two tons. Like blue whales, male elephant seals are extraordinarily loud; they bellow their sexual availability from miles away. 07 of 20 Biggest Bear: Polar Bear (1 Ton) The Polar Bear, the world's biggest bear. Wikimedia Commons If you're under the illusion that polar bears, grizzly bears, and pandas are comparable in size, you're wrong. Polar bears are by far the biggest—and deadliest—ursines. The largest males can reach a height of 10 feet and weigh up to a ton. The only bear that comes close is the kodiak bear; some males can reach 1,500 pounds. 08 of 20 Biggest Sirenian: West Indian Manatee (1,300 Pounds) The West Indian Manatee, the world's biggest sirenian. Wikimedia Commons The sirenians, the family of aquatic mammals that includes manatees and dugongs, are distantly related to pinnipeds and share many characteristics. At 13 feet long and 1,300 pounds, the West Indian manatee is the biggest sirenian by an accident of history: A bigger member of this breed, Steller's sea cow, went extinct in the 18th century. Some of them weighed 10 tons. 09 of 20 Biggest Equid: Grevy's Zebra (1,000 Pounds) Grevy's Zebra, the world's biggest equid. Wikimedia Commons The genus Equus comprises not only horses but also donkeys, asses, and zebras. While some domesticated horses exceed 2,000 pounds, Grevy's zebra is the world's largest wild equid; adults reach half a ton. Like many other animals on this list, Grevy's Zebra is nearing extinction; there are probably fewer than 5,000 in scattered habitats in Kenya and Ethiopia. 10 of 20 Biggest Pig: Giant Forest Hog (600 Pounds) The Giant Forest Hog, the world's biggest pig. Wikimedia Commons How big is the giant forest hog? This 600-pound pig has been known to chase African hyenas from their kill, though it's sometimes preyed on by the largest African leopards. Despite its size, the giant forest hog is relatively gentle. It is easily tamed, if not outright domesticated, and can live alongside humans. It's mostly a herbivore, scavenging meals only when it's especially hungry. 11 of 20 Biggest Cat: Siberian Tiger (500 to 600 Pounds) The Siberian Tiger, the world's biggest cat. Wikimedia Commons Male Siberian tigers weigh a whopping 500 to 600 pounds; females reach 300 to 400 pounds. Only 500 or so Siberian tigers still live in eastern Russia, and continuing ecological pressure may strip this big cat of its title. Some naturalists claim that Bengal tigers have surpassed their Siberian relatives, since they're not as endangered and are better fed. There may be as many as 2,000 Bengal tigers in India and Bangladesh. 12 of 20 Biggest Primate: Eastern Lowland Gorilla (400 Pounds) The Eastern Lowland Gorilla, the world's biggest primate. Ehlers / iStockphoto. There are two contestants for world's largest primate: the eastern lowland gorilla and the western lowland gorilla. Both live in the Congo, and by most accounts, the 400-pound eastern variety has the edge on its 350-pound western cousin, though western lowland gorillas outnumber the eastern variety by a 20-to-1 ratio. 13 of 20 Biggest Canid: Gray Wolf (200 Pounds) The Gray Wolf, the world's biggest canid. Wikimedia Commons Although some domesticated dog breeds grow larger, the consistently beefiest species of genus Canis is the gray wolf. Full-grown wolves often reach 200 pounds. Gray wolves mate for life. 14 of 20 Biggest Marsupial: Red Kangaroo (200 Pounds) The Red Kangaroo, the world's biggest marsupial. Wikimedia Commons The red kangaroo of Australia reaches five and a half feet tall and 200 pounds, making it the largest marsupial. That's not saying much considering the enormous sizes of its ancestors. The giant short-faced kangaroo weighed 500 pounds, and the giant wombat reached two tons. Male red kangaroos are much bigger than females and can cover almost 30 feet in a single leap. 15 of 20 Biggest Rodent: Capybara (150 Pounds) The Capybara, the world's biggest rodent. Wikimedia Commons A full-grown capybara, a South American rodent closely related to guinea pigs, can reach 150 pounds. But the capybara isn't the largest rodent that ever lived. The hippopotamus-size Josephoartigasia weighed a whopping two tons. 16 of 20 Biggest Armadillo: Giant Armadillo (100 Pounds) The Giant Armadillo, the world's biggest armadillo. Wikimedia Commons During the Pleistocene epoch, armadillos were the size of Volkswagen Beetles. Abandoned shells of the one-ton Glyptodon were used by early humans as shelter. Today, this comical-looking breed is represented in the record books by the 100-pound giant armadillo of South America. 17 of 20 Biggest Lagomorph: European Hare (15 Pounds) The European Hare, the world's biggest lagomorph. Wikimedia Commons The 15-pound European hare is by far the world's biggest lagomorph,a family that includes rabbits, hares, and pikas. European hares put their heft to good use: In the spring, females can be seen rearing back on their hind legs and swatting males in the face, either to refuse an invitation to mate or to see what kind of stuff their prospective mates are made of. 18 of 20 Biggest Hedgehog: Greater Moonrat (5 Pounds) The Greater Moonrat, the world's biggest hedgehog. Wikimedia Commons The five-pound greater moonrat, native to Indonesia, emits a strong, ammonia-like odor, hisses menacingly to keep enemies at bay, and prefers to live alone, except during mating season. The greater moonrat isn't much smaller than the Deinogalerix, a giant hedgehog of the Pleistocene epoch. 19 of 20 Biggest Bat: Golden-Capped Fruit Bat (3 Pounds) The Golden-Capped Fruit Bat, the world's biggest bat. Wikimedia Commons "Megabat" is the term naturalists use to describe any bat weighing more than a few ounces, and no megabat is larger than the golden-capped fruit bat of the Philippines, also known as the giant golden-capped flying fox. Fortunately for humans, fruit bats are strictly herbivorous, and they also lack the common bat's ability to echolocate, or to find distant prey by emitting sound waves reflected back to them. 20 of 20 Biggest Shrew: Hispaniolan Solenodon (2 Pounds) The Hispaniolan Solenodon, the world's biggest shrew. Wikimedia Commons The Hispaniolan solenodon, which lives on Hispaniola, the island shared by Haiti and the Dominican Republic, can reach two pounds, which may not sound like much until you realize that the vast majority of shrews weigh only a few ounces. Fortunately for the Solenodon, Hispaniola has few predators that could make it lunch.