The Salamander is a small magical lizard that lives in and feeds on fire. It can live up to six hours away from the fire from which it spawned, but it must be fed pepper to keep it alive, and when the fire from which the salamander spawned goes out, the lizard dies as well. The heat of the fire affects the color of the lizard. Salamander blood has healing properties (FB, CS8).
Fred and George once fed fireworks to an orange salamander just to see what would happen (CS8). Hagrid once provided a bonfire full of them for his third year Care of Magical Creatures class (PA12).
Commentary
Etymology
While there is a real lizard called a salamander, a popular mythology of ancient times was that salamanders were born of, or relating to, flame. This concept may come from the salamander's tendency to reside in logs. When the logs were set on fire, the salamanders would scramble out, leading to the idea that they were born amidst the flames.
Notes
The name Newt Scamander may derive from the word salamander.