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.

Gold dragons are the ones most often killed by humans, who consider their scales to be extremely valuable. These golden scales grant them a high level of protection, similar to armor, and they use this to their advantage in battle.

Modest Mouse, as her name hints, is a fairly modest, quiet dragon. She doesn't usually talk much, and usually sticks behind, but is still easily approachable. If one was to start talking to her, she would reply. She is very proud of her different achievements, and, unlike others in TerraDei's cave, doesn't mind the friendly banter of the other dragons.

However, it must be noted that she is not a mouse.