{"id":25715,"date":"2025-07-26T14:56:10","date_gmt":"2025-07-26T14:56:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/25715\/"},"modified":"2025-07-26T14:56:10","modified_gmt":"2025-07-26T14:56:10","slug":"these-dolphins-use-sea-sponges-on-their-faces-to-hunt-and-its-more-complicated-than-anyone-thought","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/25715\/","title":{"rendered":"These Dolphins Use Sea Sponges on Their Faces to Hunt and It\u2019s More Complicated Than Anyone Thought"},"content":{"rendered":"

\"Sponge <\/a>Sponge face. Some dolphins in Shark Bay use marine sponges as a fishing tool.\u00a0Credit: Eric Patterson<\/p>\n

One dolphin swam past, her nose oddly enlarged. On a closer look, the bulb was a marine sponge \u2014 wedged tightly onto her beak like a soft, fleshy glove. She was not playing. She was hunting.<\/p>\n

Off the coast of Shark Bay, Western Australia, a select group of wild bottlenose dolphins have developed one of the animal kingdom\u2019s most curious tool tricks: they forage with sponges. And not just any sponges \u2014 these dolphins choose specific, bowl-shaped ones from the ocean floor, fit them over their beaks, and then plunge their faces into the sediment in search of hidden fish.<\/p>\n

Now, a new study published in Royal Society Open Science<\/a> has revealed why so few dolphins learn this peculiar behavior and why those who do must spend years mastering it.<\/p>\n

\u201cIt has a muffling effect in the way that a mask might,\u201d Ellen Jacobs, a marine biologist at Aarhus University and co-lead author of the study, told Associated Press<\/a>. \u201cEverything looks a little bit weird, but you can still learn how to compensate.\u201d<\/p>\n

A Dolphin Culture Beneath the Waves<\/p>\n

Sponging, as scientists call it, isn\u2019t new. Researchers first noticed dolphins using sea sponges in Shark Bay back in 1984. For decades, biologists like Jacobs and Georgetown University\u2019s Janet Mann have tracked this tradition, revealing a striking pattern: only about 5% of the local dolphin population does it. The practitioners are mostly female, and the behavior is passed from mother to offspring \u2014 one of the clearest examples of non-human culture in the wild.<\/p>\n

But the new research finally shows why this tradition remains so exclusive.<\/p>\n

Using underwater recordings and sophisticated computer modeling, Jacobs and her team demonstrated that wearing a sponge interferes with the dolphins\u2019 echolocation \u2014 the same high-frequency clicks they use to \u201csee\u201d through sound. Dolphins emit these clicks from specialized tissues in their heads, and then receive the echoes through their lower jaws.<\/p>\n

\"\" <\/a>Credit: Ewa Krzyszczyk, Public Library of Science.<\/p>\n

With a sponge on their beak, those echoes become distorted. The sponge alters both the outgoing signal and the returning echo, making it harder for the dolphin to identify the exact location of prey.<\/p>\n

Still, sponge-wearing dolphins manage to make it work.<\/p>\n

\u201cThis is like hunting when you\u2019re blindfolded \u2014 you\u2019ve got to be very good, very well-trained to pull it off,\u201d said Mauricio Cantor, a marine biologist at Oregon State University who was not involved in the study.<\/p>\n

The Cost of Innovation, And the Payoff<\/p>\n

So why do they bother? Because for those who master it, the payoff is worth it.<\/p>\n

Dolphins typically chase fish in the open sea using echolocation to spot the swim bladders (air-filled sacs that help fish float), which produce strong echoes. But the fish hiding under the sand in Shark Bay\u2019s deep channels, like the barred sandperch, don\u2019t have swim bladders. That makes them almost invisible to sonar. They are also fatty and energy-rich \u2014 a nutritious meal, if you can dig them up.<\/p>\n

Without a sponge, probing for these fish would be risky. The seafloor is littered with sharp shells, rocks, and stinging animals like scorpionfish and stonefish. The sponge serves as soft armor, protecting the dolphin\u2019s sensitive snout while sweeping the sand.<\/p>\n

But learning to hunt with a sponge is anything but simple. Juvenile dolphins take years to get it right. They have to learn not just to find the right kind of sponge \u2014 typically a cone-shaped species called Echinodictyum mesenterinum \u2014 but also how to process distorted echoes. It\u2019s not just about tool use. It\u2019s about recalibrating an entire sensory system.<\/p>\n

\u201cIt takes them many years to learn this special hunting skill \u2014 not everybody sticks with it,\u201d Boris Worm, a marine ecologist at Dalhousie University who was not part of the study, told AP.<\/p>\n

The challenge may help explain why sponging remains confined to a few family lines. In Shark Bay, only the daughters (and some sons) of sponging mothers adopt the practice. Even dolphins that frequently associate with spongers rarely try it themselves.<\/p>\n

An Underwater Trade-Off<\/p>\n

To test this idea, the researchers used a technique called finite element modeling, essentially simulating dolphin sonar through a digital sponge.<\/p>\n

They tested how sound waves moved through two types of sponges: the preferred Echinodictyum, which has a cone-like shape, and a less-used basket-shaped sponge called Ircinia. The differences were striking.<\/p>\n

The cone-shaped sponge actually helped focus the dolphin\u2019s sonar beam, acting almost like an acoustic funnel. The basket-shaped sponge, in contrast, scattered the signal and dramatically weakened the returning echoes.<\/p>\n

The study also showed that barnacles growing inside the sponge tissue didn\u2019t significantly change the sound distortion. But the sponge\u2019s overall shape and structure had a major impact.<\/p>\n

That might help explain why dolphins favor certain sponge species. In 35 years of data from Shark Bay, about 70% of the sponges used are Echinodictyum, compared to only 20% Ircinia. This choice could be strategic. A cone-shaped sponge may reduce the sonar distortion and give the dolphin a clearer read on buried prey.<\/p>\n

A Maternal Inheritance<\/p>\n

But even with the best sponge, hunting this way is not for amateurs. Dolphin calves spend three to four years with their mothers, observing their every move. This long dependency period, which is rare in the animal kingdom, gives them time to absorb the complex skill.<\/p>\n

\u201c[Sponging] is only ever passed down from mother to offspring,\u201d said Mann, a co-author of the study and longtime expert in dolphin behavior.<\/p>\n

Despite this close maternal bond, not all offspring adopt the technique. Daughters are more likely to sponge than sons. And male dolphins that do try it tend to give it up. Researchers believe that\u2019s because males prioritize social bonding over foraging precision, a strategy that helps them later secure mates.<\/p>\n

In contrast, females \u2014 who must feed and raise calves over several years \u2014 benefit more from developing efficient, specialized hunting skills.<\/p>\n

Tool use often comes at a cost: it\u2019s time-consuming, difficult to learn, and only worth it if there\u2019s a reliable payoff. Like Gal\u00e1pagos finches that use cactus spines to extract insects only when food is scarce, dolphins turn to sponging to access prey that would otherwise remain hidden.<\/p>\n

Nevertheless, tool use among dolphins remains rather rare. Even among animals known for intelligence \u2014 chimps, crows, otters \u2014 tools are often a niche behavior. But the case of Shark Bay\u2019s sponging dolphins shows how a small cultural innovation can persist for decades, passed down through family lines.<\/p>\n

And now, thanks to advanced modeling and years of fieldwork, scientists are beginning to understand why.<\/p>\n","protected":false},"excerpt":{"rendered":"Sponge face. Some dolphins in Shark Bay use marine sponges as a fishing tool.\u00a0Credit: Eric Patterson One dolphin…\n","protected":false},"author":2,"featured_media":25716,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[49,48,20812,10390,66,20813,323],"class_list":{"0":"post-25715","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-wildlife","8":"tag-ca","9":"tag-canada","10":"tag-cultural-transmission","11":"tag-dolphins","12":"tag-science","13":"tag-sponges","14":"tag-wildlife"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/25715","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=25715"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/25715\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/25716"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=25715"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=25715"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=25715"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}