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.

Two headed dragons are a special breed of dragons. They have two necks, two brains, two mouths, but one stomach and one main body. The two heads usually work together, but there are times when they will fight each other, attacking back and forth. They use their sharp teeth and wings to hunt large animals, and rarely eat plants. It is unknown what would happen if a two headed dragon were to mate with a one headed dragon, since it has never occurred. They only mate within their breed.

Daniel Jackson is the oldest dragon in Emmaline's cave, and he is in charge of all the others. Though the two heads get along pretty well but for some squabbling, they actually have very different personalities. Daniel is very intellectual and enjoys discovering new things, and applying things he has learned in the past to new situations. Jackson, who prefers to be called Jack, is the more dominant of the two. He is fierce and always ready to strike before he is struck, and is very protective of both Daniel and all the other dragons in the cave. They both share one common dream: to someday fly up so high that they reach one of the beautifully glowing stars in space.