Ed, I don't get the National Geographic channel so I can't see his show, I guess. I googled the show and watched some great clips showing him taking control back from a "swimming pool hogging" retriever and a very scary Chihuahua with a lot of teeth. I'd really like to see the show, and hope my provider adds the channel.
The clips I watched showed him to be a very calm, gentle man who is able to teach people to expect and receive polite behavior from their animal companions. I'm lucky -- all mine are naturally sweet and when they "take over", it's just lying on MY chair or talking me into another serving of food (which can be dangerous for them at times). But that CHIHUAHUA with all those teeth was growling and snapping...

The only time I've crossed a street to avoid a dog -- it was a chihuahua -- with very big teeth glinting in the sunlight...

It looked like the dog whisperer did what my friend does with her snarly Chihuahua -- put his fist in her mouth when she attacked. Looked like it worked without ripping him up, but I don't know if I could find that much nerve...