The giant shark megalodon gave us a few scary movies and single-handedly kept Shark Week going for several years. But this huge predatory fish died out millions of years ago. What we know about them mainly comes from teeth, because they shed teeth throughout their lives, and those huge numbers of teeth were more likely to fossilize and remain with us than bones. But those teeth are enough to show us how big megalodons grew, what they ate, and where they went. When they disappeared 3.5 million years ago, it led to other species having the freedom to grow big as well. Various species may come and go, but the ocean always has its monsters. -via Damn Interesting