When Discovery/BBC's Life, an 11-part follow-up to 2007's Planet Earth, premieres Sunday (8 ET/PT), viewers will see rarely viewed scenes of nature. Among them: the frantic mating ritual of one of Earth's largest mammals, the humpback whale. How does a crew capture an event like the "heat run," where a dozen or more 40-ton males chase a single female, muscling one another aside until only one remains? Very carefully. Underwater cameraman Roger Munns and BBC producer Ted Oakes explain:

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