Lots of animals use tools. Most live on land, although a few aquatic species are equally resourceful. Octopuses use coconut shells as armour, for example, and some dolphins stick sponges on their noses to protect their skin from getting scraped when foraging on the ocean floor. In all these cases, though, a found object is used unchanged. What has never been seen before in the marine realm is the deliberate transformation of a found object into a tool. In a paper published in Current Biology this week, Michael Weiss at the Centre for Whale Research in Washington, and colleagues, report that orcas do just that to create an exfoliant from kelp.