Carlton's comment "Now what the hell ya suppose is eatin' them two guys?" is not typical of any gender. Rather, it exemplifies the desensitizing that living by oneself effects in the "bindle stiffs." In Chapter 2 when Slim and George first meet, Slim comments,
"Ain't many guys travel around together....I don't know why. Maybe ever'body in the whole damn world is scared of each other."
Further, in Chapter 3, as Slim and George play cards, George remarks,
"I seen the guys that go around on the ranches alone. That ain't no good. They don't have no fun. After a long time they get mean. They get wantin' to fight all the time."
"Yeah, they get mean," Slim agreed. "They get so they don't want to talk to nobody."
The predatory human tendencies emerge in men who do not socialize. And, ironically, the strength to oppress others is itself born of weakness. The characters such as Carlton are rendered helpless by their isolation; however, even at their weakest the men seek to destroy one another or speak callously. For, their powerlessness makes them cruel, as is Carlton.
Throughout the novel Of Mice and Men, Carlton proves to be a very arrogant, insensitive, and destructive. Carlton proves his insensitivity and destructiveness through the demand of the killing of Candy's dog. The fact that the dog meant everything to Candy means nothing to Carlton. The only thing which matters to him is his own superiority and callousness.
Therefore, the end of the novel makes sense because it shows the brutal nature of the farm hand and transient. While he has been at the farm for a while, some things never seem to die in a person. He cares nothing for the men who move in and out of his life based upon his own arrogance.
His line at the end of the novel, "Now what the hell ya suppose is eatin' them two guys?," shows his attitude about mankind, his typical lack of emotion and understanding, and the inability to see past the surface of anything.