From Creatures Wikia
The Spike Norns are a breed for Creatures 2 drawn by Kari, with body data by Alien. They have a distinctive long tail, and come in varying shades of green. The males develop spikes on their back during the child life stage, and have a cyan cast to their fur, while the females have a yellowish cast and muzzle-spots. Both have sharper ears than most other breeds.