Baby mammals have to learn a lot of things, like where to find food, how to defend themselves, how take care of young, and so much more! Where do they learn these life skills? From their mother! In fact, after birth, an elephant calf (baby) depends on its mother to take care of it for 2-3 years!
Mammals are every where! Do you have a pet dog or cat? They're mammals! Have you ever seen a squerril or rabbit? That's also a mammal! Look in a mirror. You'll see a mammals looking back at you!