For many sea creatures, regrowing a lost limb is routine. But when a young jellyfish loses a tentacle or two to the jaws of a sea turtle, for example, it rearranges its remaining limbs to ensure it can still eat and swim properly, according to a new study published June 15 in Proceedings of the National Academy of Sciences. The discovery should excite marine enthusiasts and roboteers alike, the authors say, because the jellyfish’s strategy for self-repair may teach investigators how to build robots that can heal themselves. “It’s another example of nature having solved a problem that we engineers have been trying to figure out for a long time,” says John Dabiri, a biophysicist at Stanford University who had discussed the project with the study investigators but was not involved with the research.