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PNAS u March 22, 2011 u vol. 108 u no. 12 u 4697–4698 www.pnas.org/cgi/doi/10.1073/iti1211108 Researchers studying animal cognition have long debated the basis of successful cooperation among some animals during the performance of goal-oriented tasks. Whereas some reports suggest that cooperation is a result of the animals’ coincidental moves, others indicate deliberate coordination to accomplish a given task. Joshua Plotnik et al. (pp. 5116– 5121) modified an established experimental setup to test the ability of elephants at a conservation center in Lampang, Thailand, to cooperate deliberately. To obtain a food reward, two elephants had to simultaneously pull two ends of the same rope with their trunks. The authors placed each end of the rope in a separate, fenced lane into which each elephant in the pair was released—at once or at different times. Only when both rope ends were pulled simultaneously did a table bearing food slide within the elephants’ reach. By and large, the authors report, the elephants not only cooperated successfully in the task but also waited for delayed partners before pulling their end of the rope. In addition, the elephants appeared to distinguish between partners with and without access to the rope. The findings suggest that elephants pay attention to their partners’ presence and actions when engaged in cooperative tasks. Such partner-oriented attention reveals a propensity toward deliberate cooperation, according to the authors. — P.N. Elephants wait for a helping trunk