Groucho is usually the Peyton Manning of elephants, "a perfect gentleman," says Denver Zoo large animal curator Dale Leeds. In his view, "Groucho is a mature male with self-confidence," not unlike the Broncos's seasoned quarterback. "Peyton Manning doesn't have to get on TV, scream and shout about how great he is, scream and shout about how everybody else is bad. He knows he's good. He doesn't have to sell it."

But when Groucho is in musth -- as he was from late August until very recently -- it's a different story.