New Caledonian crows (Corvus moneduloides) are well-known for their sophisticated tool use. According to a new study, these birds behave optimistically after tool use. The findings, published in the journal Current Biology, raise the possibility that enjoyment may be a fundamental cause in the evolution of tool use and other complex behaviors. A New Caledonian crow (Corvus moneduloides). Image credit: Jolyon Troscianko. “What this suggests is that,...