Did you Know? Ghost crabs grumble using their stomach teeth.
Crabs' claws may be able to frighten other species, but if that isn't enough, ghost crabs will snarl at their foes like a dog. Crabs, unlike our canine companions, generate these terrifying noises with fangs placed in their guts. They are part of the stomach's gastric mill machinery, where they rub against one other to grind up food.
In 1931, a scientist decided to undertake an experiment in which he raised a monkey as if it were a person.