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.

Guardian dragons have large shields on the end of their tails. Although the shields appear to be heavy, they are light, yet nearly unbreakable. Guardian dragons use their tail-shields, as well as their wings, to deflect attacks and protect others. Often, they will guard the eggs and hatchlings of a nest while others are away. They are generally peaceful, and will not retaliate unless necessary. They have no need to forage or hunt, as they are fed by those they protect.

A cornerstone of the cave's defenses, Sanrei's name means guardian spirit of the mountain.  It is very appropriate, since he is ever watchful and scanning for danger.  One time he protected the whole brood of hatchlings from attack by a rival dragon troop by herding them into a small alcove and blocking the entrance with his tail.  When not on guard detail, he likes to use his shield-like tail for other purposes.  Sanrei is a favorite of the unattached females of the cave. They help him keep a brilliant shine on his tail, which he will then use to reflect the sunlight and send visual cues to dragons ranging out in the area.  In easier times, he will also use it to scoop up hatchlings and fling them into the lake, catapult-style.  The young ones thoroughly enjoy this, especially those who can't fly on their own.