Fish Walked First

Around 375 million years ago, certain lobe-finned fish started hauling themselves onto land. One of them, Tiktaalik, had fins with wrist-like joints, a flat head with eyes on top, and a real neck — features sitting halfway between a fish and a four-legged animal.

They didn't crawl out because land looked inviting. Shallow swamps ran low on oxygen during dry seasons, so these fish gulped air at the surface and dragged themselves from one shrinking pool to the next. The first steps onto land were desperate survival, not adventure.