The ending is even more sad if you think about it.
Tara does not have the tools to survive in the wild. She doesn't have the claws, teeth, fur or metabolism. Even if she did survive for a time in the wild, come winter, she would die cold and alone from exposure. And to make it more worse, the movie seems to indicate she still has a small memory of her former self. Overall, it is one of the most tragic endings I have seen.
I saw the tv version and the DVD, and the DVD was edited, for one thing, in the tv version it appears that Tara killed Madeleine Stowe's character at her lab, in the DVD that scene was cut. I like to think that eventually, Tara regains her sanity and lives normally.
I agree that it's a tragic ending, but not that it's the most tragic ending ever.
Abandoned by her 'boyfriend', left by the only family she's ever known, forced to be naked for the rest of her entire life in a deserted forest, because no person would even dare to come close to her. It all seems to be a tragic ending for Tara.
But wait, there's still hope. There's still a pack of wolves in the forest. Maybe that's Tara's true family. She can join them and be happy. In that way, she can have the one thing she always dreamed of: a family of her own.
I know it may sound strange, but look at Romulus and Remus, 2 girls in Roman mythology, who were raised by wolfs. So, it may be possible for Tara to be raised by a pack of wolves for the rest of her entire life.
Tara losing hair and turning into a wolf on the inside wouldn't necessarily mean that her metabolism hasn't changed, now would it? IMO, she didn't change her looks, but she did change her metabolism. In that way, she could go through winter without having a cold. Maybe the serum she was injected with, didn't only change her behavior, but her metabolism as well.