Laying eggs is thought to be the original way that animals evolved to reproduce. Live births evolved later on in many different animals, many different times. Egg-laying is known as oviparity.1 Animals like birds, turtles, crocodiles, alligators, and fish lay eggs. Some species of snake also lay eggs.2
Egg-laying has some advantages. For example, females that lay eggs don’t need to carry their offspring for as long as females that give live birth. This allows them to not divert as many physical resources to their offspring that pregnant females usually have to.1
Laying eggs also allows the mother to have more offspring than if she had to physically carry them. The amount of offspring she has isn’t limited to how big her body is and what she can carry. She also is able to have a more genetically diverse group of offspring if she has more than one clutch of eggs. Genetic diversity keeps animals healthier and stronger than if their gene pool is very small.2
Check out more about eggs in this article!