Mermaid makeover

 Animal Planet's "Mermaids: The Body Found" presents an evolutionary scenario for a marine primate species. /See more video at animal.discovery.com

This Animal Planet production goes out on a precarious limb of the primate family tree. The full-length version of "Mermaids: The Body Found" is intriguing.

Ever wonder about the widespread reports of dolphins chasing sharks away from humans swimming in the open ocean? ("Dolphin rescues swimmer" yields 1.5 million Google search results.) One of the more interesting lines of speculation in "Mermaids: The Body Found" contends that mermaid-like marine primates hunt fish in cooperation with dolphins, which would explain why they have been observed repeatedly helping Homo sapiens.

But just as there's probably no Santa Claus, there's probably no mermaids. The science and conspiracy theory drama in "Mermaids" has drawn howling criticism.

On a deadly serious note, "Mermaids" makes a powerful environmental case against U.S. Navy tests of new sonar technology apparently capable of use as a sonic weapon. Chasing mermaids may have dented their credibility, but "Mermaids" is far from alone in linking Navy sonar tests to mass strandings of marine mammals including dolphins and whales.

More than 30 pilot whales were among marine mammals stranded alive on North Carolina beaches in January 2005 at the same time Navy vessels were conducting sonar tests in the area. NOAA's report on the strandings, which were investigated as an Unusual Mortality Event, concluded the sonar tests were a likely cause of the strandings. /U.S. National Marine Fisheries Service photo