How does the hound react to Montag?

The very first reaction we are apprised of in the novel is the hound's growl at Montag.

"Montag touched the muzzle. .

The Hound growled.

Montag jumped back.

The Hound half rose in its kennel and looked at him with green-blue neon light flickering in its suddenly activated eyebulbs. It growled again, a strange rasping combination of electrical sizzle, a frying sound, a scraping of metal, a turning of cogs that seemed rusty and ancient with suspicion."