Birds lay eggs, although there are other egg-laying animals, including two mammals: the duckbill platypus and the echidna. These two creatures are natives of Australia. Scientists call these primitive egg-laying mammals monotremes.
Most reptiles lay eggs; however, some snakes have live births. According to Nature World News, a recent discovery by scientists show that ancient snakes and lizards all gave live birth. Egg laying was an evolutionary change to ensure survival of the offspring. Only 2,000 of the 10,000 modern species of lizards and snakes have live births, while the rest lay eggs.
Sea turtles lay eggs. While the male and female mate at sea, the female comes ashore to lay her eggs, normally at high tide. She digs a pit in which she deposits 50 to 200 eggs. She covers the eggs with sand, spending only a couple of hours out of the water. She may repeat the process several times during the session.
In seahorses, the female deposits the eggs into a pouch located on her mate's abdomen. The male fertilizes the eggs in the pouch and they develop there, depending on nourishment from their yolk sacs. Once the embryos develop, the male gives birth to new seahorses.