Bruce eats what he can, but stops when he realizes that they have company. His ears fold back submissively, but then one of the dogs is sniffing Betty a little too interested and his head perks up with a grunt.

With his giant mass, he can safely stand over the small dog, his paws on either side of her as he gives a weak growl. It's nothing threatening, but it's a warning they should go find somewhere else to eat.

So you're a tough guy? Let's see you take on the whole pack. The other dogs don't take it well, and there's a returned growl, this one clearly more threatening.

Bruce whimpers a little, but the feeling of the fur at his feet bolsters him to stand his ground. He tries a calm, low woof. He's a big dog, he has a big voice. Maybe he can intimidate them?