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Whales roll in seaweed as a play toy and also use it for its antibacterial properties

Humpback whales have been engaging in a unique behavior involving seaweed. Experts believe that whales are not just using seaweed for play, but also for its antibacterial properties.

This intriguing behavior is documented in a paper by Dr. Olaf Meynecke of Griffith University. The research is published in the Journal of Marine Science and Engineering.

Sand scrubs 

In previous work, Dr. Meynecke described whales rolling in sandy substrates off the Gold Coast during their migration, presumably to shed dead skin cells and parasites. 


The new paper delves into another understudied behavior displayed by baleen whales, including humpbacks, across various populations in the northern and southern hemispheres. The whales have been seen frolicking and rolling around with clumps of kelp and seaweed at the water’s surface.

According to Dr. Meynecke, the behavior was similar in different individuals, regardless of where in the world it occurred.  

Focus of the research 

For the investigation, three instances of “kelping” behavior on Australia’s east coast were scrutinized through aerial observations, alongside 100 other documented seaweed interactions worldwide. 

These interactions involved 163 baleen whales with the majority being humpbacks (in 95 separate events), followed by gray whales, southern right whales, and northern right whales. 

Complex behaviors 

“The use of objects by cetaceans like baleen whales is well known, and their ability to interact with their environment in complex behaviors has been previously reported on,” said Dr. Meynecke. “But baleen whales, including humpback whales, are less often observed to perform object use, and this behavior might be more common than previously thought.” 

“There are two plausible theories: play and/or self-medication with seaweed. This behavior may be playful but could also serve additional benefits in the context of learning and socialising, as well as ectoparasite removal and skin treatment by using brown algae’s antibacterial properties.” 

Dr. Meynecke emphasizes that recognizing this behavior across various whale populations is crucial for understanding the species’ habitat preferences. It also sheds light on the intricate behaviors of whales, about which there is still much to discover.

Playful behavior among whales

Whales, despite their immense size, often engage in playful behavior, demonstrating both their intelligence and their social nature. 


One of the most dramatic and easily noticeable behaviors, a breach involves the whale leaping out of the water and then crashing back down with a splash. It’s believed this may help to dislodge parasites or simply be a form of play.

Tail slapping

Whales might slap their tails (flukes) on the water’s surface. This can serve as a form of communication, a way to stun prey, or even just play.


This is when a whale vertically pokes its head out of the water to take a look around, possibly to scout its surroundings.


Similar to tail slapping, but the whale will stick its tail out of the water and wave it around before smacking it down.

Log rolling

Whales, especially young ones, are sometimes observed rolling around in the water, which can be a playful activity or a way to dislodge parasites.

Playing with seaweed

Some whales have been observed playing with seaweed, passing it between their fins or tossing it around.

Interacting with other species

Whales are known to occasionally interact playfully with other marine animals, such as dolphins. For example, orcas (killer whales) and dolphins have been seen playing together, chasing each other, and even sliding on each other’s wakes.

Bubble blowing

Some whales will release a stream of bubbles as they swim, which could serve various purposes including hunting, communication, or simply play.

The reasons behind these behaviors aren’t always clear and could be a combination of play, communication, and practical necessity. Nevertheless, these playful activities offer a glimpse into the complex social and cognitive lives of these magnificent marine mammals.

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