The original version of this article unfortunately contained mistakes in the Discussion and Acknowledgments sections. The changes are shown below: 1. In the second paragraph of the Discussion section, line 10, it reads: ‘In addition, a difference in decay rates of sticks between the north and south would not account for the fact that more ponerine tools were found to the north than to the south (although the difference was not significant), vs. the opposite pattern for Dorylus tools.’ The actual pattern found was the opposite of this, of course: significantly more epigaeic Dorylus tools were found to the north than to the south, while (nonsignificantly) more ponerine tools were found to the south. 2. In the Acknowledgments section, Adam Darby-Singh’s family name was incorrectly spelled as “Darby-Si Singh”. The authors apologize for these errors.