Different animals behave in different ways when it comes to rearing their young. Some rear their young in pairs, others alone, others do not care for their young at all.
Whatever happens, the species will not die out. Frogs and tortoises, for example, leave their eggs after laying them. But the number of eggs is so great that at least some are bound to survive.
Vipers and rattle-snakes give birth to young ones which are already independent, so they do not have to take care of them.
The female cobra, on the other hand, is the only snake which cares for her young, even though they are independent as soon as they are born. Other animals, such as mammals and birds care for their young for a long time.
— Credit: The Big Book of How? When? Why?