This shark can live for over 300 years

Greenland sharks grow so slowly that scientists couldn't age them by normal methods, so a 2016 study radiocarbon-dated proteins locked in the crystalline lens of their eyes instead — tissue that forms before birth and never changes after. The oldest shark tested was estimated at roughly 390 years old, making it the longest-lived vertebrate known, older than any whale, tortoise or human.

— Julius Nielsen et al., Eye Lens Radiocarbon Reveals Centuries of Longevity in the Greenland Shark — Science, 2016