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.

Mint colored dragons are the most peaceful of all dragons; they only eat plants unless they scavenge meat from an already dead animal. They also have no ways to attack others or defend themselves. They are much smaller than other forms of dragons since they only double in size when they mature. Mint dragons are unable to use magic and cannot fly since they lack wings. Their looks have given rise to the common insult of calling dragons "large lizards."

Vaccine is a nondescript Mint dragon.  He keeps to himself, not usually bothering the other dragons in the cave.  He is pleasant enough, but is very shy around the older dragons and around females.  However, when one dragon is being rude, Vaccine can turn very cold towards that dragon.

Most of the more powerful female dragons in the cave think that Vaccine is adorable.  Stone, Vine, and Gold dragons have accepted him as a mate, but to their dismay, the eggs they laid were usually Mint eggs, and abandoned by the human who tends their cave.