🐘 Mammals

Mammals have hair or fur (a whale has a few whiskers), breathe air, and feed their babies milk. Most are born alive rather than hatching. People are mammals too.

The biggest and the smallest here: the blue whale and the little brown bat

🧒 our measuring child, 4 ft1.2 m🐋 Blue whale, 110 ft33.5 m long🦇 Little brown bat, 10 in26 cm long🔍 Pip the pangolin zoomed in 50 times on the little brown bat

⚖️ Compare them

What makes a mammal?

Hair or fur on their bodies, even if only a few whiskers.
They breathe air with lungs, even the ones that live in the sea.
Mothers feed their babies milk.
Most are born alive instead of hatching from an egg.

52 animals here

Record holders here

Fastest: the cheetah, 60 to 70 mph96 to 112 km/h1
Heaviest: the blue whale, 165 tons150 tonnes2
Lives longest: the beluga whale, 90 years90 years3

Mammals for kids, A to Z

🐘 African elephant: The biggest land animal, with a trunk for smelling, drinking and hugging.
🦬 American bison: The biggest land animal in North America, and it can run fast.
🦊 Arctic fox: An Arctic fox turns from brown to white when winter comes.
🐘 Asian elephant: Asia's elephant: smaller ears than the African one, the same clever trunk.
🐋 Beluga whale: The white whale nicknamed the canary of the sea for its chirps.
🐋 Blue whale: The biggest animal that has ever lived, bigger than any dinosaur.
🦧 Bornean orangutan: Orangutan means "person of the forest" in the Malay language.
🐬 Bottlenose dolphin: Each dolphin has its own whistle that works like a name.
🦭 California sea lion: It barks loudly and can walk on land using its big front flippers.
🐹 Capybara: The biggest rodent in the world, and a very good swimmer.
🐱 Cat: A soft, quiet pet that purrs, naps and pounces on toys.
🐆 Cheetah: The fastest runner on land, built light and long like a greyhound.
🐒 Chimpanzee: A clever ape that uses sticks as tools to fish for termites.
🐺 Coyote: A clever wild dog whose yips and howls fill the night.
🐶 Dog: Our oldest animal friend, in every size from tiny to giant.
🐿️ Eastern gray squirrel: Squirrels help plant trees by forgetting where they buried nuts.
🦊 Fennec fox: The smallest fox, with giant ears that help it stay cool.
🐼 Giant panda: A bear with a special wrist bone that works like a thumb.
🦒 Giraffe: The tallest animal alive: it eats leaves from the tops of trees.
🐺 Gray wolf: A wild cousin of the dog that lives and travels in a pack.
🦓 Grévy's zebra: The biggest kind of zebra, with thin stripes and big round ears.
🐻 Grizzly bear: A big brown bear with a shoulder hump, strong enough to dig.
🦭 Harbor seal: A seal whose whiskers can feel where a fish has just swum.
🐴 Horse: A big, strong animal that gallops, carries riders and pulls carts.
🐋 Humpback whale: Male humpbacks sing long songs that other whales learn and copy.
🐆 Jaguar: The biggest cat in the Americas, and it loves to swim.
🐨 Koala: Koalas have fingerprints that look a lot like yours.
🦁 Lion: The only big cat that lives in a family group, called a pride.
🦇 Little brown bat: A bat is the only mammal that really flies, and it eats mosquitoes.
🦡 Meerkat: One meerkat stands guard on its back legs while the family eats.
🦌 Moose: The biggest deer in the world, and a surprisingly good swimmer.
🦬 Musk ox: A shaggy Arctic animal with hair that nearly reaches the ground.
🐋 Narwhal: A narwhal's long twisty tusk is really a tooth, not a horn.
🦫 North American beaver: Beavers build dams of sticks and mud to make their own ponds.
🦦 North American river otter: A playful swimmer that slides down muddy banks and snowy hills.
🐳 Orca: Orcas live in close families that are often led by a grandmother.
🐻‍❄️ Polar bear: The biggest bear, at home on the frozen Arctic sea ice.
🦌 Pronghorn: The fastest land animal in North America, and not a real antelope.
🐰 Rabbit: A pet with long ears and a fluffy tail that hops.
🦝 Raccoon: A raccoon feels its food with sensitive hands, often dunking it in water.
🦊 Red fox: A red fox can hear a mouse squeaking under deep snow.
🦘 Red kangaroo: The biggest animal that hops, carrying its baby in a pouch.
🦌 Reindeer (caribou): Both male and female reindeer grow antlers, which they shed each year.
🦦 Sea otter: Sea otters hold hands while they sleep so they don't drift apart.
🐋 Sperm whale: The biggest toothed whale, and one of the deepest divers of all.
🦥 Three-toed sloth: The slowest mammal, hanging upside down in the rainforest trees.
🐅 Tiger: The biggest wild cat, with stripes that hide it in tall grass.
🦭 Walrus: A walrus uses its tusks like ice picks to climb onto the ice.
🐋 West Indian manatee: A gentle plant-eater of warm water, and a cousin of the elephant.
🦍 Western gorilla: A gentle giant that builds a new leafy bed every night.
🦏 White rhinoceros: A huge grass-eater with horns made of the same stuff as fingernails.
🦌 White-tailed deer: A white-tailed deer flashes its white tail to warn other deer.

Smithsonian's National Zoo, Cheetah, checked 30 October 2026.
NOAA Fisheries, checked 30 October 2026.
NOAA Fisheries, checked 30 October 2026.