The animal is actually a coyote (but wolf is also sufficient). The coyote/wolf symbolizes Vincient, the assassin. In the making-of documentary found in the movie DVD special features, the director's only remark about the scene goes something like, "I was in LA once when some coyotes crossed an intersection, stopping all the traffic. And there's just something commanding about their presence. They don't even seem to stop to notice you, it is as if they own the scene." Tom Cruise also said something to the effect of, "When I was reading it in the script, it was just one sentence in there, and I was wondering what the hell Michael (the director) was going to do with it. But the moment it was shot, and that moment in the film, something just stops, and there's something completely poetic about that moment." Basically, the coyote represents the loneliness and, at the same time, commanding presence that is Vincient. It is a break from the nihilistic attitude that Vincient has held throughout the whole movie, where he stops to actually reflect upon what he is doing. If you read his face during the scene, you can see this whole, "What the hell has my life amounted to?" thought going through his head. Another scene that would closely relate to this one would be the scene where Vincient kills Daniel. The moment he shoots him and holds his head up so it doesn't make a loud noise crashing into the table, watch carefully as the shot goes to a closeup of Vincient's face. For a brief second, you see his conscience kicking in, and he's probably thinking, "Oh my God, what have I done?" and then as abruptly as that face appeared, you can see him snap back into Vincient the Killer Assassin-mode. These are a couple of the few moments in the film where we see a human side to Vincient. At least, those are my conclusions, based on the extra commentaries and etc. that I have read on this movie. This movie is really something, almost a literary art of sorts. It is chocked full of symbolisms and imageries (like the coyote), and that's what makes it one of my favorite movies. Hope that answers your question!