The mascot of the Fire department in "Fahrenheit 451" is the mechanical hound. This "dog" is used for sniffing out offenders and has the ability to kill people who are hiding illegal books. The hound has a needle in its nose and the needle is full of poison.
The mechanical hound begins to take an interest in Montag and when Montag comes to work the hound stalks him and acts like he is going to inject Montag with poison. Montag talks to Captain Beatty about the problem and he promises to fix the hound, but nothing changes. Montag gets very nervous and uncomfortable around the hound. We learn that Montag is indeed hiding books and the hound can detect the fear in Montag.
There are actually two possible answers to this question depending upon what you mean by mascot. The most obvious would be the Mechanical Hound. The Mechanical Hound is the electronic dog that assists the fire department in seeking out people who are reading and breaking laws. The Mechanical Hound is the dog that follows Montag around and makes him extremely nervous and paranoid throughout the end of “The Hearth and the Salamander”. A second possibility is more of a symbol of the fire department and also become a symbol of the firemen since they wear one on their uniforms.
In my opinion, the salamander is the mascot of the fire department throughout the novel Fahrenheit 451. Each firefighter has a patch of a salamander sewn onto the sleeve of their uniform, and their firetruck is also referred to as the salamander. According to mythology, salamanders were creatures that could withstand fire and their name even derives from the Greek word meaning "fire-lizard." Like the salamander on their uniforms, the firefighters in Bradbury's dystopian society make their living setting books on fire. Their occupation relies on the fact that they can use and manipulate fire to destroy books and homes. The salamander is an appropriate mascot for the fire department because it symbolizes their purpose in the dystopian society. Like the salamanders, the firefighters live among the flames without being harmed.