Researchers have found that male bottlenose dolphins can form third-level alliances when trying to mate with a female. A third-level alliance is where a group of dolphins joins another to fend off a rival group. Such alliances are more sophisticated partnerships than even chimpanzees form. Researchers say they place “considerable demands” on the dolphins’ social cognition. In another study, researchers have found that female bottlenose dolphins maintain large networks of relatives and friends to help them have more calves and protect their young.