Dragons are creatures with nearly unlimited life spans. They can survive for long periods of time, and no one has found a dragon that has died of old age. Adolescence 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. Once they hit adolescence, hatchlings change quickly, maturing to their full forms in only 2 years.

Dragons don't communicate with each other verbally, but they will growl to scare off predators and frighten prey. Young dragons will emit an extremely high-pitched squeal when they are frightened. To communicate, they use telepathy with each other and to speak to other creatures.

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.

Although she is a good stone dragon, Duridel seems to think that she is, or should be, a guardian dragon.  It's a little hard to be certain, though.  Most of the time she can be found in the cave's nursery, standing stiff and still outside the entrance along with the more usual guardians.  As both breeds of dragon tend to spend a lot of time not moving around, it's difficult to know whether Duri is slightly delusional, or just likes the spot.