Animal Group

Mammal Facts For Kids

From tiny shrews to giant whales, mammals are warm-blooded animals that breathe air, grow hair or fur, and feed their babies milk. Meet the three groups of mammals and learn what makes each one special!

Quick Mammal Facts

How many kinds?
Over 6,400 known species of mammals
Body covering
Hair or fur (even whales have a little hair!)
Body temperature
Warm-blooded, stays the same in hot or cold weather
Baby food
Mothers feed their babies milk
Breathing
Lungs (mammals breathe air, even ocean mammals)
Smallest
Bumblebee bat, about the size of a thumb
Largest
Blue whale, longer than three school buses

Monotremes: The Egg-Laying Mammals

Monotremes are the rarest kind of mammal, and the only mammals that lay eggs instead of having live babies! Only five species of monotremes live on Earth today, and they all live in Australia or New Guinea. After their babies hatch, mother monotremes still feed them milk, just like other mammals. Monotremes have special features that no other mammals have, like duck-like bills and webbed feet.

Featured animals: Platypuses, Echidnas

Marsupials: The Pouch Mammals

Marsupials are mammals that carry their babies in pouches! Most marsupials live in Australia, but a few live in the Americas. Marsupial babies are born very tiny and helpless. They climb into mom's pouch and stay there for weeks or months, drinking milk and growing strong. Once they are big enough, they peek out of the pouch and start exploring the world.

Featured animals: Kangaroos, Koalas, Opossums, Tasmanian Devils

Placental Mammals: The Largest Group

Most mammals are placental mammals! Their babies grow inside mom's body until they are ready to be born. Placental mammals live almost everywhere on Earth: in oceans, forests, deserts, jungles, and even the freezing Arctic. They are split into smaller groups based on what they eat and how they live.

Carnivores: The Meat Eaters

Carnivores have sharp teeth and strong jaws for hunting and eating meat. Lions, Tigers, Wolves, and Bears are all carnivores.

Herbivores: The Plant Eaters

Herbivores eat plants, leaves, grass, fruit, or bark. Elephants, Giraffes, Zebras, and Horses are herbivores.

Aquatic Mammals: The Ocean Mammals

Aquatic mammals spend their lives in water but still breathe air. Whales, Dolphins, and Manatees are aquatic mammals.

Primates: The Clever Climbers

Primates have hands that can grip and big brains for solving problems. Chimpanzees, Gorillas, and Monkeys are primates.

Insectivores: The Bug Hunters

Insectivores eat insects and small bugs. Anteaters, Bats, and Pangolins are insectivores.

Omnivores: The Anything-Eaters

Omnivores eat both meat AND plants. Rodents like mice and squirrels are omnivores.

Cool Facts About Mammals!

  • Whales sing songs! Humpback whales sing songs that last up to 30 minutes. Whales from the same area sing the same song, and they change it a little every year.
  • Bats are the only flying mammals! No other mammal can truly fly. Flying squirrels glide, but bats actually flap their wings and fly like birds.
  • Otters hold hands when they sleep! Sea otters float on their backs and hold paws so they don't drift apart while they nap on the ocean.
  • Elephants greet each other! When elephants meet, they touch trunks like a hug. They also flap their ears and make rumbling sounds to say hello.
  • Some mammals live 200 years! Bowhead whales can live more than 200 years, making them the longest-living mammals on Earth.

Mammal Questions Kids Ask

Are humans mammals?

Yes! Humans are mammals too. We are warm-blooded, we breathe air, we have hair, and mothers feed babies milk. Humans are a special kind of mammal called primates.

Why are whales mammals and not fish?

Whales breathe air with lungs, are warm-blooded, give birth to live babies, and feed them milk. Fish breathe through gills and lay eggs. Even though whales live in water, they are mammals.

What is the smartest mammal?

After humans, dolphins and chimpanzees are among the smartest mammals. They can solve puzzles, use tools, and recognize themselves in mirrors!

Do all mammals have fur?

Almost all mammals have hair or fur somewhere on their bodies, even if it is just a few strands. Whales and dolphins have a tiny bit of hair when they are born, but they lose most of it as they grow.

What is the fastest mammal?

The cheetah! Cheetahs can run 70 miles per hour in short bursts, making them the fastest mammals on land. The fastest swimming mammal is the dolphin.