Cooperative hunting, resource sharing, and using the same signals to communicate the same information—these are all examples of cultural sharing that have been observed between distinct animal species. In an opinion piece published June 19 in the journal Trends in Ecology & Evolution, researchers introduce the term "co-culture" to describe cultural sharing between animal species. These relationships are mutual and go beyond one species watching and mimicking another species' behavior—in co-cultures, both species influence each other in substantial ways.