1. Testing optimal foraging theory in a penguin–krill system by Yuuki Y. Watanabe, Motohiro Ito, and Akinori Takahashi Proceedings B Volume 281(1779):20132376 March 22, 2014 ©2014 by The Royal Society

2. Illustration and schematic diagram showing how optimal patch residence time will change in response to patch quality according to the MVT. (a) Consider an animal foraging in an environment where prey patches are heterogeneously distributed. Yuuki Y. Watanabe et al. Proc. R. Soc. B 2014;281:20132376 ©2014 by The Royal Society

3. An example of successive diving activities, called a ‘dive bout’, of an Adélie penguin with the number of krill capture events in each dive. Yuuki Y. Watanabe et al. Proc. R. Soc. B 2014;281:20132376 ©2014 by The Royal Society

4. Gain function analyses. Yuuki Y. Watanabe et al. Proc. R. Soc. B 2014;281:20132376 ©2014 by The Royal Society

5. Partial regression plots (i.e. the relationship between the response variable and a predictor, with the other predictors held constant [20]) from a linear mixed model (dive duration = dive depth + dive-scale patch quality + bout-scale patch quality) with bi... Yuuki Y. Watanabe et al. Proc. R. Soc. B 2014;281:20132376 ©2014 by The Royal Society