In 'Fahrenheit 451', what is the name of the mechanical animal used to hunt dissidents?

In Ray Bradbury’s Fahrenheit 451, the mechanical animal used to hunt dissidents is the Mechanical Hound.

The Mechanical Hound is an eight-legged robotic creature kept at the firehouse, where it helps the firemen track people who hide books or challenge the state’s censorship system. It can identify a target by scent and pursue that person with frightening speed and precision. Its animal shape makes the machine feel both technological and instinctive: a manufactured weapon that behaves like a trained predator.

The Hound becomes particularly important when Guy Montag begins questioning his work as a fireman. After Montag kills Captain Beatty and escapes, the authorities release a Mechanical Hound to pursue him while helicopters and television crews turn the chase into public entertainment. Montag injures the Hound with a flamethrower but cannot prevent the state from broadcasting a substitute victim’s death as his own.

The novel’s other animal symbols cause common confusion. The salamander is associated with the firemen and their vehicles, while the phoenix represents destruction followed by renewal. Neither is the robotic tracker; that role belongs specifically to the Mechanical Hound.