A character trait to describe Whitney is sympathetic. This was shown indirectly, through what Whitney says. Whitney shows this during his conversation with Rainsford when they discussed how it might feel to be hunted. “‘Even so, I rather think they understand one thing--fear. The fear of pain and the fear of death.’” This quote shows how he cares about how the jaguar might feel to be hunted and feels bad for it.
A character trait that fits Rainsford well is being cool under pressure. This is an indirect characterization, through what Rainsford does. When the hunt begins, Rainsford doesn’t lose his nerve. “He had plunged along, spurred on by the sharp rowers of something very like panic. Now he had got a grip on himself, had stopped, and was taking stock of himself and the situation.” This shows that he has the focus to make smart decisions in a panic.
A good character trait to describe General Zaroff is unfeeling. This is an indirect reference - it's based off what he says. Zaroff thinks he is fair and doesn’t consider how the people he hunts’ feels. “This is really an inspiration. I drink to a foeman worthy of my steel - at last." The general raised his glass, but Rainsford sat staring at him.” He seems to think that Rainsford would think the same, not that he would be scared or nervous.