Dolphins Use Sponges to Soak Up Special Snacks
As if we need another reason to be impressed with the smarts of dolphins, new research has uncovered conclusive evidence that that they use tools intelligently to collect certain kinds of food that they couldn’t get otherwise.
Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Shark Bay off the coast of Australia have long been observed with sponges on their snouts as they poke and probe the bottom for food. This is a common practice – surveys of activity in the bay estimate that 60 percent of all female dolphins do this and up to half of all males born to “spongers” pick up the ability themselves. It appears the dolphins use the sponges while digging to protect their snouts from rock injuries and bites and stings from other species. But do they also use them as a tool to capture food they couldn’t get otherwise?
As reported in the in the journal Proceedings of the Royal Society B., evolutionary biologists Michael Krützen and Sina Kreicker at the University of Zurich found the answer by analyzing tissue samples from 11 sponge-using dolphins and 27 that didn’t. The fatty acids in the tissues differed enough to conclude that the sponge users had a completely different diet.
The researchers speculate that pushing the sponge allows the dolphins to find organisms on the dark sea bottom that others cannot using just their echolocation sonar. Without a detailed list of the fatty acids of all creatures living in the bay, they can’t identify which ones the dolphins catch with their sponges.
Whatever the case, it’s another amazing dolphin talent. What would make them even more human-like is if their children came over on weekends and “sponged” off of them.