Why did our ancestors ditch the shell and start growing babies inside their bodies instead? In this episode of Big Ideas, ...

Snakes, like most reptiles in the world, are oviparous. This means that rather than producing live young ones, the way mammals do, snakes produce an immature single cell — an egg. Most snakes follow ...

Birds may be the most famous egg-layers, but they’re far from the only ones! Across the animal kingdom, reptiles, amphibians, fish, and even a few rare mammals rely on this ancient method of ...