Shark facts
Short facts, and straight answers to things people say about sharks. Every one lists where we found it.
Short facts, and straight answers to things people say about sharks. Every one lists where we found it.
Long ago
Most fossil shark teeth are found in layers of rock from places that used to be shallow sea, such as parts of Florida. Water wears away the sediment and uncovers them, so beaches at low tide and creek beds can be good places to look.
Sources: Florida Museum: Five facts about fossil shark teeth in Florida, Florida Museum: Five facts about megalodon
Long ago
Helicoprion lived about 270 to 290 million years ago and had a spiral of teeth in its lower jaw, like a round buzz saw. It was not a true shark: its closest living relatives are the deep-sea ratfish.
Long ago
Megalodon lived from roughly 20 million to about 3 million years ago. Scientists think it grew to around 15 to 18 metres (50 to 60 feet) long, but they work that out from teeth and a few backbone pieces, because no complete skeleton has been found.
Sources: Florida Museum: Five facts about megalodon, National Geographic: Maybe megalodon wasn't so chonky after all
Long ago
A 2019 study of fossils suggested that Megalodon was probably gone by about 3.6 million years ago. Researchers think great white sharks may have played a part, but the cause is still debated.
Long ago
Sharks have been around for at least 400 million years. That is before the first trees, about 385 million years ago, and well before the first dinosaurs, about 230 million years ago.
Sources: BBC Discover Wildlife: Are sharks older than trees?, Natural History Museum: Where did dinosaurs come from?
Long ago
Small sharks survived the Great Dying, about 250 million years ago, perhaps by moving into deeper water. Shark teeth also show that sharks stayed fairly varied when the dinosaurs died out 66 million years ago, although some big predators among them were lost.
Sources: Science News Explores: How sharks survived the Great Dying, ScienceDaily: Shark diversity unaffected when dinosaurs were wiped out
Long ago
Scientists estimate a shark's age by counting pairs of light and dark bands in its backbone, a bit like tree rings. NOAA researchers found the bands are tied to how fast the shark grows, not to years, so some older sharks have been guessed to be younger than they are.
Sources: NOAA Fisheries: Shark vertebral band pairs are related to growth, not time