Stone Dragons have a tough outer covering made of a stone-like material. They eat rocks, using the minerals they contain for nourishment and to keep up their stone outer shell. They rarely move, and are the heaviest of all types of dragons. Although they have wings, indicating flight ability, no one has ever seen a stone dragon flying.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons is usually marked by the growth of a hatchling’s wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. In Galsreim, dragons and humans coexist peacefully.

JumboJim seems to see himself as a sort of gargoyle.  As is typical of stone dragons, he's never been seen flying, but his incredibly strong limbs has given him climbing abilities that are the envy of the dragon world.  He can often be seen perched on the top of a castle or mountain cliff as if protecting his realm, coming down only occasionally to breed or to find some rock or mineral to eat that doesn't seem to be available from his normal perch.