All mammals have fur or hair and they produce milk to feed their babies. Giraffes, bears, kangaroos, elephants, and people are all mammals.
It’s usually the female mammals who choose a mate, so the males want the females to look at them. Leopards make marks on trees with their claws so that the females will know they are there. Other animals make special smells.
Males often fight with each other to win a mate. Male giraffes fight with their head and neck to show which animal is the strongest.
Most mammals do not lay eggs. The babies grow inside the mother’s body, and they get food and oxygen from a special part of the body called the placenta. This is called gestation.
The gestation time for shrews is only two weeks, but for African elephants it’s 22 months!
When mammals are ready to have their babies, many look for safe, quiet places. Polar bears dig special dens in the snow so that their babies will be warm and safe.
Some baby mammals grow a lot inside their mother’s body, and they can stand up as soon as they are born. Other baby mammals can’t see or move when they are born. Mammals produce milk for their babies, and this is the only food or drink that they need at first.
Marsupials are animals like kangaroos and koalas. Baby marsupials only grow for a short time inside their mother’s body. After they are born, they continue to grow on the outside of their mother’s body, usually in a pouch. Baby kangaroos are only 5 centimeters long when they are born. They climb into their mother’s pouch, where they stay for up to a year.
Mammals are different from many other types of animal because they feed and care for their babies. Anteaters carry their babies on their back for the first year, and elephants stay near their mother until they are ten years old. Baby mammals learn from their parents, and they learn by playing, too.
Life is very dangerous for a lot of animals. Many are killed by predators. Also, people hunt them and damage their habitats — the places where they live.
Many animals die before they become adults, but if they grow up, then they can produce young. This is all part of their life cycle. Because of this, there will always be millions of species of animal on Earth, if we care for them and their habitats.