The tail might just be another aspect of Mortensen's feral charm. Or it could be the defining feature of an uncredited butt double. There's even a good chance it was added by director David Cronenberg (The Fly, Naked Lunch), an old-school horror virtuoso with a taste for fleshiness. In any case, it suits the moment and Mortensen's character Tom. Until then, Tom had spent the lazy opening of the film as a small-town husband with two children, a drawl and a diner. Maria Bello was his spouse, in charge of scheduling and lovemaking.
One night, however, while cleaning up after his last customers, Tom stops a violent crime with some violence of his own, and becomes a local celebrity. His animal side is exposed -- exposed to him, his family, his community, and the world at large. Very quickly, Tom's actions rip through the invisible and accepted seams that run through his home: the simmering spite between father and son, the coiled ferocity of protective parents, the sexual tension between lovers.
Each time an act of violence shatters the story's steady pacing, Cronenberg cuts into his film with the same degree of aggression. It's an example of what only film and video can achieve: the simple act of editing becomes an embodiment of violence. The result is uncomfortable. The violence is not hidden behind anonymous explosions or seriously spoken statistics. It is about bodies being snapped, noses being broken, backs being bruised. When we discuss acts of violence, whether criminal actions or legal acts of war, we are talking about hurting another person's body to either please or protect ourselves. A History of Violence tilts explicitly toward these dark, animal truths, and finds them resting at the backbone of humanity. (Rated R)