Dolphins’ sponge tools reveal culture-driven hunting in Shark Bay
Rare footage from Shark Bay shows bottlenose dolphins using sea sponges as protective tools on their snouts to hunt along the seafloor. The behavior alters echolocation and is transmitted from mothers to offspring; only about 5% of the population uses it, and calves typically learn it over 3–4 years. Sponge shape changes the acoustic beam, affecting hunting efficiency, with cone-shaped sponges guiding clicks more narrowly than basket-like sponges. The study, led by Ellen Rose Jacobs of Aarhus University and the Shark Bay Dolphin Research Project, highlights cultural transmission and the costs of tool use in a changing ocean, and was published in Royal Society Open Science.