And that's when his heart's working

From the February, 2006 Esquire (no link) "The Answer Fella"

Q: Pound for pound what's the world's fiercest mammal?

A: Dick Cheney says hi.

Kidding aside, you've got three contenders, all member of the same taxonomical family, Mustelidae. All feature a high level of aggression, blinding quickness, powerful jaws, and a nasty proclivity for going after an opponent's neck - or testicles.

Whereas Dick Cheney's not so quick.