Got this from the Pokemon site... Seems fitting:
BiologyPhysiology
It appears that Graveler is a living boulder. Its skin becomes tougher when it evolves. It also has four arms, but mainly uses the longer two to lift things, using the shorter two as a defense against attackers.
Gender differences
None.
Special abilities
They often roll down mountain paths at high speeds, crushing objects in the way.
Behavior
Graveler are very reckless, often rolling down hills and flattening anything in their way.
Habitat
Mountain PokémonGraveler can be often found on mountain trails or in caves.