Australian dolphins have been spotted using a unique, if somewhat goofy-looking, method to hunt for fish: wearing sponges on their noses. In a study published to Royal Society Open Science, researchers analyzed this behavior, and the tradeoffs dolphins who use it have to overcome.

“Sponge tool use is a foraging technique restricted to a small subpopulation of bottlenose dolphins in Shark Bay, Australia,” explains the study, which further elaborates that the dolphins “carry basket sponges on their beaks to probe the seafloor and flush out camouflaged fish, widening the search area and protecting the beak from abrasion.”

However, while the sponges are useful tools to help sift through rubble without injury, there are some tradeoffs. Most notably, it affects the dolphins’ use of echolocation, in which they navigate by emitting high pitched sounds and listening for their echoes.

“It has a muffling effect in the way that a mask might,” co-author Ellen Rose Jacobs, a marine biologist at the University of Aarhus in Denmark, explained to Phys.org. “Everything looks a little bit weird, but you can still learn how to compensate.”

To find out exactly how they compensate, the scientists created digital models to simulate echolocation through various sponges. They found that the echolocation signal was indeed changed, and that dolphins in turn “adaptively and flexibly compensate during neural signal processing.”

The difficulty of mastering the process also explains why so few dolphins actually use it – only about five percent of the Shark Bay dolphin population, or around 30 animals in total. Those who successfully learn the technique are invariably taught by their mothers during their formative years.

“The difficulty of mastering this combination could explain why the behavior is strictly vertically transmitted among a small proportion of the population,” concluded the researchers. “An extended period of learning and observation, facilitated by the dependent calf period, could be necessary to master the technique, providing insight into how tool use can spread through some, but not all, of the members of a population.”