In the story, the General says that a human being is the ideal animal to hunt. He maintains that a human being possesses three traits that an animal does not. First, the human being has the capacity to be courageous. Second, a human being possesses the ability to deceive. Third, a human being has the ability to think logically.
The General argues that these three traits make human beings ideal quarries. In the story, the General tells Rainsford that he only hunts the "scum of the earth," the sailors from "tramp ships." Tramp ships are ships that don't follow any particular route or adhere to any particular schedule. They are essentially cargo ships for hire, moving material on demand. The word "tramp" refers to "beggar" or "vagabond." Tramp ships have to petition merchants for work; they are independent contractors and are not affiliated with any maritime company.
Since many of these ships hire unsavory characters, Rainsford believes that these men should be fair game in his diabolical sport.
If I wish to hunt, why should I not? I hunt the scum of the earth: sailors from tramp ships—lassars, blacks, Chinese, whites, mongrels—a thoroughbred horse or hound is worth more than a score of them."
To the General, sailors from tramp ships have just enough cunning, courage, and analytical ability to make the "hunt" interesting for him. He boasts that he has always prevailed in any hunt against the sailors. It's obvious that winning feeds the General's considerable ego.