In Fahrenheit 451, why did Ray Bradbury choose the phoenix and the salamander as symbols?

Ray Bradbury's classic of science fiction literature, Fahrenheit 451, evokes symbolism associated with the role of fire in his story and with the notion of rebirth following destruction. Most prominent in this respect is his use of the mythological Phoenix, a bird that represents immortality and vision, and that continues to rise from the ashes of physical destruction. In Bradbury's story, the main character, Guy Montag, is a fireman. In the dystopian futuristic society depicted in Fahrenheit 451, however, firemen do not extinguish fires; rather, they are dispatched to burn books, which are banned by the totalitarian regime that governs this fictional world, and to burn down the homes of those discovered to be in possession of these sources of knowledge. Early in his narrative, Bradbury depicts Montag's encounter with the teenage girl Clarisse, describing her reaction to the symbols on Montag's uniform: "she seemed hypnotized by the salamander on his arm and the phoenix-disc on his chest." The firemen wear uniforms with the Phoenix and with salamanders, real-life animals that, in ancient times, were believed to represent fire and the being that can pass through the flames unharmed. Both of these creatures, one entirely mythological, the other real but identified with fire, are used by Bradbury to denote the paradoxical relationship between the firemen in his story and the fire, destruction, and resurrection they represent. The image of a salamander, it should be noted, is engraved on the lighters the firemen carry, a further association of this animal with the flames of destruction. When Faber describes his plan for the destruction of the firemen, the "praetorian guard" of this autocratic regime, by insidiously planting books within their own structures and then exposing the illicit activity, he tells Montag,

"It's an insidious plan, if I do say so myself. . .To see the firehouses burn across the land, destroyed as hotbeds of treason. The salamander devours his tail! Ho, God!"

So integral to his narrative is the mythological association of the salamander to fire and destruction that Bradbury even calls the fire trucks used by Montag and his colleagues "Salamanders." It is the Phoenix, however, that represents resurrection, in this case, the new civilization that will rise from the ashes of the destroyed city that Montag, and others before him, fled. After Montag flees the city, he encounters others who have fled tyranny, and who have devoted themselves to preserving the knowledge contained in the books the physical form of which have long been destroyed. That is why, as his story approaches its conclusion, the leader of these defectors refers to the Phoenix that will rise out of the ashes of the now-devastated city:

"Granger looked into the fire. 'Phoenix'."

"What?"

"There was a silly damn bird called a Phoenix back before Christ: every few hundred years he built a pyre and burned himself up. He must have been first cousin to Man. But every time he burnt himself up he sprang out of the ashes, he got himself born all over again. And it looks like we're doing the same thing, over and over, but we've got one damn thing the Phoenix never had."

The "one damn thing," of course, is the knowledge of society's destruction and, more importantly, the knowledge of how to rebuild society. Unlike the salamander, the Phoenix holds promise of redemption.