Mammal

Mammal is the name for animals that share three main traits: they are warm-blooded vertebrates, they have hair or fur at some point in life, and mothers produce milk to feed their young. These features appear in tiny shrews, giant whales, flying bats, and even humans, showing how flexible the mammal body plan can be.

Mammals regulate their internal temperature using fat layers, fur, sweat glands, and behavior. arctic foxes curl tails over their faces, camels conserve water with narrow nostrils, and dolphins carry a thick blubber layer that keeps heat in while swimming through cold water. This warm-blooded strategy lets mammals stay active day or night and in many climates.

Teeth and jaws reveal how mammals eat. Herbivores such as cows have broad molars for grinding plants, carnivores like lions wield sharp canines for slicing meat, and omnivores like bears mix both sets. Mammals also chew differently than reptiles; their lower jaws move sideways and up-and-down, which helps break food into small pieces before swallowing.

Mammals use advanced senses and social behaviors. Bats send out high-pitched calls and read echoes to fly in the dark, elephants communicate using low rumbles felt through the ground, and prairie dogs have alarm calls with distinct meanings. Many species care for their young for months or years, teaching them how to find food, avoid danger, and cooperate with the group.

Scientists classify mammals into three major groups. Monotremes such as the platypus lay eggs, marsupials such as kangaroos carry early-born young in pouches, and placental mammals like wolves, whales, and people develop babies inside the uterus until birth. Fossils show that mammals first appeared alongside dinosaurs, and their ability to adapt has helped them spread worldwide.