Shark

The Greenland shark is the longest-living vertebrate. In 2016, radiocarbon dating aged one female at ~400 years; the species may reach 272–512. The secret is a metabolism crawling in the cold, deep Arctic. It takes ~150 years to mature — so one maturing today was born in the 1600s.

Sharks have no real tongue — just a small slab of cartilage, the basihyal, on the mouth floor. Useless in most species, it is the cookiecutter shark's key weapon: the shark latches on, retracts its mobile basihyal to create a vacuum, then twists out a round plug of flesh.

Sharks appeared on Earth before Trees. The oldest known shark scale Fossils date to about 450 million years ago in the late Ordovician period, while the first trees only appeared around 385 million years ago in the Devonian. Sharks predate trees by roughly 65 million years.

Some sharks enter a state of 'tonic immobility' when flipped upside down, becoming completely paralyzed. In 1997, an orca was observed exploiting this by ramming a larger shark, flipping it over, and holding it immobile for 15 minutes before eating it.