Behaviour 154 (2017) 1069–1079 brill.com/beh Is righting response lateralized in two species of freshwater turtles? Geoffrey R. Smith a,∗ , Jessica E. Rettig a and John B. Iverson b a Department of Biology, Denison University, Granville, OH 43023, USA b Department of Biology, Earlham College, Richmond, IN 47374, USA * Corresponding author’s e-mail address: smithg@denison.edu Received 18 August 2016; initial decision 15 December 2016; revised 8 September 2017; accepted 30 September 2017; published online 19 October 2017 Abstract Laterality has been found in a variety of reptiles. In turtles, one important behaviour is the righting response. Here, we studied laterality of righting response of two species of freshwater turtles, the Painted Turtle (Chrysemys picta) and the Eastern Musk Turtle (Sternotherus odoratus). We found evidence of individual-level laterality in righting response in C. picta, but not S. odoratus. Neither species showed evidence of population-level laterality in righting response. Our results suggest that there is variation in the extent of laterality of righting response in turtles. Possible explanations for variation in laterality of righting response in turtles include shell shape and use of terrestrial habitats. However, more species of turtles need to be examined to demonstrate any general patterns in laterality of righting response in turtles. Keywords Chrysemys picta, laterality, righting response, Sternotherus odoratus, turtle. 1. Introduction Lateralization of behaviours at the individual level exists when individuals show a left or right bias in the behaviour. Lateralization at the population level exists when most or all individuals in a population show the same type of lateralization (e.g., left-biased or right-biased). Lateralization of be- haviours at the individual level may benefit the individual if it allows the two brain hemispheres to focus on different tasks, thus allowing multi-tasking (Dadda & Bisazza, 2006; Vallortigara, 2006). The benefits of population- level laterality are less obvious since, for example, if all individuals in a  Koninklijke Brill NV, Leiden, 2017 DOI 10.1163/1568539X-00003458