Snapping turtles were once used to find dead bodies in lakes

Snappers prey on anything they can catch or overpower. They also scavenge food.

Using this to their advange, people would attach a snapper to a rope, and release it into the water.When the reptile stopped moving, the tracers knew that it must have found a body and begun to feed.

Another fun fact about the Snapper: In some areas of Thailand, these turtles are covered in gold leafs and kept in temples

(Source)