Humpback whales are well known for their fascinating culture: These mysterious animals migrate thousands of miles every year, sing charming songs, leap from the water in an enormous breach, and collaborate while hunting--creating bubble nets that trap their prey. Now, researchers have shed light on another aspect of whale behavior: Playing with kelp(巨藻) they find floating in the ocean—moving it between their fins, rolling around with it, and, most interestingly, wearing it atop their heads like a hat.
This behavior—called kelping—has been described in a new study as a "global phenomenon" . There's no doubt kelping looks fun. But could it have another purpose? Olaf Meynecke, research fellow at Griffith University and co-author of the study, thinks so--especially considering that whales can keep it up for 30 to 40 minutes.
What's particularly intriguing about kelping is the way that humpbacks from different populations—in both the Northern and Southern Hemispheres—all prefer to wear seaweed on the top of their heads, says Meynecke. They place kelp on their forehead in over half the recorded instances Baleen species are believed to like having their heads scratched--gray whales are known for approaching whale watching boats for a tickle on the nose. Because whales don't have hands to scratch themselves, like we do, Meynecke suggests "they might seek out other tactile sensations that just feel good".
Whales might also be treating kelp like a cleansing face mask, as seaweed has antimicrobial qualities that can reduce levels of bacteria. Rubbing kelp across their bodies may also remove parasites(寄生物) and shed bacterial and viral growths to prevent them getting completely overgrown with sea lice(虱) and skin infections, says Meynecke.
The study has caught the attention of researchers globally, and Meynecke's mailbox has been flooded with people who have also seen kelping. "Someone from Tahiti was like, ‘We see it all the time,' " he says. Now the phenomenon has been highlighted globally, which could lead to further research into the behavior, its benefits, and even if other species do it.