The crow in the room: New Caledonian crows offer insight into the necessary and sufficient conditions for cumulative cultural evolution.

New Caledonian (NC) crow populations have developed complex tools that show suggestive evidence of cumulative change. These tool designs, therefore, appear to be the product of cumulative technological culture (CTC). We suggest that tool-using NC crows offer highly useful data for current debates over the necessary and sufficient conditions for the emergence of CTC.