with tools. Current Biology 17:412–17.
Raby, C. R., D. M. Alexis, A. Dickinson, and N. S. Clayton. 2007. Planning for the future by western scrub-jays. Nature 445:919–21.
Rajala, A. Z., K. R. Reininger, K. M. Lancaster, and L. C. Populin. 2010. Rhesus monkeys ( Macaca mulatta ) do recognize themselves in the mirror: Implications for the evolution of self-recognition. Plos ONE 5:e12865.
Range, F., L. Horn, Z. Viranyi, and L. Huber. 2008. The absence of reward induces inequity aversion in dogs. Proceedings of the National Academy of Sciences USA 106:340–45.
Range, F., and Z. Virányi. 2014. Wolves are better imitators of conspecifics than dogs. Plos ONE 9:e86559.
Reiss, D., and L. Marino. 2001. Mirror self-recognition in the bottlenose dolphin: A case of cognitive convergence. Proceedings of the National Academy of Sciences USA 98:5937–42.
Roberts, A. I., S.-J. Vick, S. G. B. Roberts, and C. R. Menzel. 2014. Chimpanzees modify intentional gestures to coordinate a search for hidden food. Nature Communications 5:3088.
Roberts, W. A. 2012. Evidence for future cognition in animals. Learning and Motivation 43:169–80.
Rochat, P. 2003. Five levels of self-awareness as they unfold early in life. Consciousness and Cognition 12:717–31.
Röell, R. 1996. De Wereld van Instinct: Niko Tinbergen en het Ontstaan van de Ethologie in Nederland (1920–1950). Rotterdam: Erasmus.
Romanes, G. J. 1882. Animal Intelligence. London: Kegan, Paul, and Trench.
———. 1884. Mental Evolution in Animals. New York: Appleton.
Sacks, O. 1985. The Man Who Mistook His Wife for a Hat. London: Picador.
Saito, A., and K. Shinozuka. 2013. Vocal recognition of owners by domestic cats ( Felis catus ). Animal Cognition 16:685–90.
Sanz, C. M., C. Schöning, and D. B. Morgan. 2010. Chimpanzees prey on army ants with specialized tool set. American Journal of Primatology 72:17–24.
Sapolsky, R. 2010. Language. May 21, http://bit.ly/1BUEv9L.
Satel, S., and S. O. Lilienfeld. 2013. Brain Washed: The Seductive Appeal of Mindless Neuroscience. New York: Basic Books.
Savage-Rumbaugh, S., and R. Lewin. 1994. Kanzi: The Ape at the Brink of the Human Mind. New York: Wiley.
Sayigh, L. S., et al. 1999. Individual recognition in wild bottlenose dolphins: A field test using playback experiments. Animal Behaviour 57:41–50.
Schel, M. A., et al. 2013. Chimpanzee alarm call production meets key criteria for intentionality. Plos ONE 8:e76674.
Schusterman, R. J., C. Reichmuth Kastak, and D. Kastak. 2003. Equivalence classification as an approach to social knowledge: From sea lions to simians. In Animal Social Complexity , ed. F. B. M. de Waal and P. L. Tyack, 179–206. Cambridge, MA: Harvard University Press.
Semendeferi, K., A. Lu, N. Schenker, and H. Damasio. 2002. Humans and great apes share a large frontal cortex. Nature Neuroscience 5:272–76.
Sheehan, M. J., and E. A. Tibbetts. 2011. Specialized face learning is associated with individual recognition in paper wasps. Science 334:1272–75.
Shettleworth, S. J. 1993. Varieties of learning and memory in animals. Journal of Experimental Psychology: Animal Behavior Processes 19:5–14.
———. 2007. Planning for breakfast. Nature 445:825–26.
———. 2010. Q&A. Current Biology 20: R910–11.
———. 2012. Fundamentals of Comparative Cognition. Oxford: Oxford University Press.
Siebenaler, J. B., and D. K. Caldwell. 1956. Cooperation among adult dolphins. Journal of Mammalogy 37:126–28.
Silberberg, A., and D. Kearns. 2009. Memory for the order of briefly presented numerals in humans as a function of practice. Animal Cognition 12:405–7.
Skinner, B. F. 1938. The Behavior of Organisms . New York: Appleton-Century-Crofts.
———. 1956. A case history of the scientific method. American Psychologist 11:221–33.
———. 1969. Contingencies of Reinforcement. New York: Appleton-Century-Crofts.
Slocombe, K., and K. Zuberbühler. 2007. Chimpanzees modify recruitment screams as a