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.

Beneath Boulder's stony exterior lies a soft heart. As his moves and thoughts are slow and ponderous, he finds it difficult to keep up with his burrowmates' much faster conversations and interactions. This makes him feel fairly lonely, even though he lives in a busy burrow full of adult dragons and hatchlings of all types.

Only his mate Charcoal takes the time to slow down to his speed of thought and movement and he loves it when she uses her fiery flame to melt some particularly tasty rocks for him to slurp up.