(A) Long-tailed macaque (M. fascicularis) on Koram Island in the Khao Sam Roi Yot National Park, Thailand. Luncz et al. report that macaques on this island are using stone tools to overharvest local shellfish populations. Photograph: Amanda Tan. (B) Juvenile capuchin monkey (Sapajus sp.) in the Tietê Ecological Park in São Paulo, Brazil, cracking a nut with a stone tool. Photograph: Tiago Falótico. (C) An adult chimpanzee (Pan troglodytes) uses a stone tool, as a juvenile chimpanzee looks on, in the Taï National Park, Côte d'Ivoire. Photograph: Liran Samuni/Taï Chimpanzee Project. (D) Meriam Islander Sonia Passi and her son JJ Passi, Mer Island, Torres Strait, Australia, collecting and processing spider conch, or asor, in Meriam Mir (Lambis lambis). Photograph: Douglas Bird.