Some 20 million years back, a colossal apex predator fish emerged in Earth’s oceans before going extinct about 3.6 million years ago. Initially thought to be related to the great white shark, megalodons were the last members of a now long dead lineage of sharks. As far as sharks go, the megalodon remains unmatched in size.

Here’s what we know about the biggest shark ever to swim the oceans:

• The megalodon’s teeth were roughly three times the size of a great white shark’s. The largest tooth on record is 6.9 inches (18 centimeters) long! Most of what we know about megalodons is thanks to their fossilized teeth because sharks don’t have bones.
• Megalodons preferred warmer water and likely went extinct due to a period of global cooling. Their preference for warmer environments is why their fossils can be found around the world except for Antarctica.
• Female megalodons were twice as large as their male counterparts. Estimates vary, but the largest of these ancient giant sharks is about 60 feet (18.2 meters), bigger than a school bus!
• What did megalodons eat? Pretty much any marine creature they wanted. Their diet consisted of anything from fish and seals to dolphins and whales. Based on their size, they likely ate around 2,500 (1133 kilograms) pounds of food daily.
• Although megalodons were the largest ocean predators, they competed for prey with macroraptorial or leviathan whales and possibly the ancestors of killer whales.
• Most fish are cold-blooded, but the megalodon may have been partially warm-blooded.