Some researchers claim that cetaceans – whales and dolphins – have culture, which the researchers define as the ability to learn from one another. Skeptics, however, demand clear evidence that cetaceans can acquire new behaviors through some form of social learning, preferably clear-cut instances of imitation or teaching. But such evidence is difficult to obtain. While few people doubt that captive cetaceans are adept at imitation or that they reproduce behaviors taught by researchers, biologists seeking insight into cetaceans' behavior in their natural habitats must rely on deduction rather than experiments. If members of a particular group share behaviors that do not result from genetic inheritance or environmental variation, then they have almost certainly learned them by watching, following, or listening to other animals.