Mammals

Mammals are a diverse group found on every continent, from polar to tropical regions. They include animals that live on land, fly or spend their lives in water.

What are mammals?

Mammals are vertebrates whose young receive milk produced by mammary glands. Most give birth to live young. Hair or fur is another characteristic, and all mammals breathe air with lungs, including whales and dolphins.

Main characteristics of mammals

• Mostly live-bearing: most give birth to live young, with egg-laying mammals as exceptions.
• Milk: females produce milk to feed their young.
• Internal heat production: mammals generate heat within the body, although temperature regulation varies.
• Lungs: aquatic mammals must also breathe air.
• Hair: its amount varies, and it can be very sparse in some species.

Examples of mammals

• Wild mammals: lions, tigers, bears, elephants and wolves.
• Domestic mammals: dogs, cats, cattle and horses.
• Marine mammals: dolphins, whales and seals.