Dragons (Pern)

The Dragons of Pern are a fictional race created by Anne McCaffrey as an integral part of the science fiction world depicted in her Dragonriders of Pern novels.

In creating the Pern setting, McCaffrey set out to subvert the clichés associated with dragons in European folklore and in modern fantasy fiction. Pernese dragons are similar to traditional European dragons in the fact that they can breathe fire and resemble great lizards or dinosaurs with wings, but the resemblance ends there. Unlike most dragons in previous Western literature, Pernese dragons are entirely friendly to humanity. Furthermore, they are not magical at all. Instead, they are a heavily genetically modified species based on one of Pern's native life-forms, the fire-lizard.

In Dragonsdawn, the race was intentionally engineered to fight Thread, a deadly mycorrhizoid spore that devours all organic matter that it touches, after it first caught the human colonists on Pern unawares, with devastating results. Geneticist Kitti Ping Yung designed the dragons by manipulating the genetic code of the indigenous fire-lizards that had been acquired as pets by the colonists. The dragons were named after their resemblance to European dragons from the legends of old Earth. Later genetic manipulation by Ping's granddaughter, Wind Blossom, also resulted in the watch-whers, ungainly, nocturnal creatures who bore a slight resemblance to dragons. The later novels, set during the Third Pass, have shown the watch-whers are more useful than commonly thought in the novels set in the First Pass. On Pern, time is measured in "Turns", or years, and "Passes", which are about fifty Turns long, and occur when a planet named the "Red Star" is close enough to Pern for Thread to traverse space between the Red Star and Pern. Thread only falls during Passes. Periods between Passes, when the Red Star's orbit takes it away from Pern, are referred to as "Intervals"; usually lasting about two hundred Turns. In the novels, "Long Intervals", of about four hundred and fifty Turns, have occurred twice. These Long Intervals have led the inhabitants of Pern to believe that Thread will never return.

...
Wikipedia