[Animals] What is 'kapping' and why are whales putting seaweed on their heads?

[GlaD1]

ANIMALS
What is 'kelping' and why are whales putting seaweed on their heads?
A new study sheds light on the fascinating behavior of whales. But is it a form of play or the marine equivalent of a skincare routine?

A humpback whale swims with her calf off the coast of Rarotonga, the largest of the Cook Islands in the South Pacific. Humpback whales are among the whale species known to engage in kelping, or playing with seaweed they find floating in the ocean.

Humpback whales are well known for their fascinating culture: these enigmatic animals migrate thousands of kilometers each year, sing enchanting songs, leap out of the water in a huge gap, and collaborate while hunting, creating webs of bubbles that trap their prey.

Now, researchers have shed light on another aspect of whale behavior: playing with seaweed they find floating in the ocean, moving it between their fins, rolling with it and, most intriguingly, carrying it on their heads like a hat.

This behavior, baptized in English as kelping (which could be translated as alguear), has been described in a new study as a "global phenomenon." The study documents cases of humpback whales (Megaptera novaeangliae) around the world interacting with seaweed, based on more than 100 social media posts, and shows that this playful behavior is much more common than previously thought.

There's no doubt that seaweed looks like fun. But could it have another purpose? Olaf Meynecke, a researcher at Griffith University (Australia) and co-author of the study, believes so, especially considering that whales can spend between 30 and 40 minutes with this behavior.

"That's a long time to spend with a little piece of seaweed," he says. "It seemed like there had to be something more."

Meynecke believes that the way they can move the algae smoothly and precisely with all parts of their body could indicate mobility training: whales need dexterity and coordination to feed. It may also create a sense of comfort for the whales and be beneficial for their skin.

(Related: Can humpback whales be altruistic?)

A whale plays in seaweed in the Bay of Fundy, which is located between the Canadian provinces of New Brunswick and Nova Scotia.

SHUTTERSTOCK PHOTOGRAPHY
How long have whales been 'sleeping'?
Kelping was first observed in 2007, and it's not just humpback whales that do it. Other baleen species have also been observed interacting with seaweed such as gray whales and northern and southern right whales.

After watching videos of seaweed and reading a 2012 study on the phenomenon, Meynecke became intrigued. After watching three unrelated drone videos of kelping algae, he wondered how much more there was behind those images.

To gather more data on this strange behavior, he searched social media for keywords like "kelping," "humpback whale," "whale," and "algae," and found hundreds of posts, which the team thoroughly analyzed.

Meynecke says it became clear that this behavior is not accidental: "Having something touch your body in the water is quite difficult because it doesn't really want to stick, it floats away," he says.

Heidi Pearson, a professor of marine biology at the University of Alaska Southeast, who was not involved in the research, has seen seaweed at her humpback whale research site in Juneau, Alaska. Once, a female named Barnacles appeared to be tangled in a fishing line. It turned out that she "was playing with these seaweed" placed on her back.

But "I've never documented it in a quantitative way," she says, adding that she "didn't know the word for it was kelping."

https://www.nationalgeographic.es/animales/2023/10/kelping-que-es-por-que-ballenas-ponen-algas-cabeza