To Give Birth, Sharks Return to Own Birthplace

A mother shark can be away from her birthplace for years—but she'll still return there when it's time for her to have babies, scientists have found in a 17-year-study. Researchers suspected as much, but to confirm their suspicions, they decided to follow individual lemon sharks starting in 1995; that's when they tagged babies and "toddlers" with transponders and took tissue samples. For each of the next 17 years, researchers headed back to the site, tagging newly-born creatures. Their findings were released just this week, the Los Angeles Times reports.

The first sharks were expected to be ready to give birth in 2008. Researchers captured two at the spot—and lo and behold, both had been IDed years earlier. Eventually, at least six such mothers were found. "Of the couple of hundred sharks that were born between 1995 and 1998, only about a dozen reached adulthood. So the fact that we found six we think is pretty significant," a lead author tells the BBC. The study suggests that it's important to conserve such nursery areas, the experts say. (More discoveries stories.)