Smooth hounds are harmless ground sharks. They teeth aren't even sharp, but instead are flat crowned teeth. These teeth are great at finely grinding their food, such as crabs, shellfish and other fish, before swallowing. The number of smooth hounds in the North Sea has increased in the past thirty years, while other shark species have declined in the same period. Smooth hounds are named after their habit to gather in large groups, like a pack of dogs (or hounds).