Louis, a 7-year-old whose full name is GCHP Sunlit’s King of Queens, showed no signs of nerves. He eyed interlopers at a haughty remove. He yawned in the face of commotion. “This dog is the most confident Afghan hound I’ve encountered in my entire life,” Ms. Jones said.

Big dogs are having their day at the Westminster Kennel Club dog show, where a bunch of massive breeds are being judged Tuesday. Although Great Danes, mastiffs, Newfoundlands and others classified as “working” dogs are competing,