Scientists have been getting up close to massive sharks to study their teeth.
Today's shark teeth can help the scientists learn more about pre-historic sea creatures.
We packed Hayley a wetsuit and sent her on a very dangerous mission, swimming in the same pool as a massive shark, in order to pick up its teeth!
They were then brought back to the lab where Hayley found out why the research is so important.
Watch the video to see how Hayley got on!