Behavioural Processes 75 (2007) 225–230 Short communication Training and long-term memory of a novel food acquisition task in a turtle (Pseudemys nelsoni) Karen M. Davis ∗ , Gordon M. Burghardt Department of Psychology, University of Tennessee, Knoxville, TN 37996-0900, USA Abstract We developed a shaping procedure for training Florida red-bellied cooters, Pseudemys nelsoni, to dislodge clear plastic bottles to obtain food pellets. The animals were then trained in a 2-choice problem to choose only the bottle containing pellets. All nine turtles learned the task of knocking over bottles for food. For the discrimination task, turtles chose the correct bottle 71% on average. After 2 months (82–84 days), and again after another 7.5 months (228 days) of no interaction with the bottles, turtles were retested and many retained both the response and the discrimination (mean success rates 77–81%), with significant savings in retraining all turtles. The turtles showed two basic response strategies, which changed across time for some individuals. This study demonstrates that turtles can learn and retain a novel skill in a laboratory context. © 2007 Elsevier B.V. All rights reserved. Keywords: Discrimination task; Food acquisition; Long-term memory; Pseudemys nelsoni; Turtles 1. Introduction The study of behavioral plasticity and cognitive processes in diverse animals has been revitalized by the recent methods and concepts of comparative cognition (e.g., Shettleworth, 1998). Although reptiles as a group have been studied less than mam- mals, birds and even fish (Shettleworth, 1998; Laland et al., 2003), turtles have been used in more learning studies than other reptile groups (see Burghardt, 1977, for review). Most of these studies were conducted 30 or more years ago and focused on visual discrimination abilities, documenting that turtles have acute visual abilities and can be trained in a number of respon- dent and instrumental learning tasks including visual and spatial reversal learning (Kirk and Bitterman, 1963; Bitterman, 1964; reviews in Burghardt, 1977; Morlock, 1989). More recently, L´ opez et al. (2000, 2001) found that turtles’ spatial learning and memory capabilities closely parallel those of mammals and birds. Turtles share a common ancestor with birds and mam- mals and are an important group for studying the evolution of cognitive abilities in vertebrates. Turtles are ideal subjects for instrumental conditioning and discrimination tasks for several reasons. For example, turtles will train for small food rewards more readily than many other ectothermic reptiles (Burghardt, 1977; Kramer, 1989a). Fur- ∗ Corresponding author. thermore, turtles (particularly many emydid turtles) are readily available, adapt and perform well under captivity, and are long- lived (Burghardt, 1977). Finally, turtles are highly visual, with the ability to discriminate shapes and colors in stationary stim- uli (e.g., Burghardt, 1977; Arnold and Neumeyer, 1987), which makes them a favored group among reptiles for visual discrim- ination learning tasks. The study species, Florida red-bellied cooters, Pseudemys nelsoni, are semi-aquatic emydid pond turtles found only in Florida. They leave the water primarily to bask and, if female, to lay eggs (Kramer, 1986). Agonistic behavior, courtship, forag- ing, and other kinds of behavior have been studied in this species in the field and captivity (Kramer, 1986, 1989a,b; Kramer and Burghardt, 1998). The goals of this research were to test whether turtles would (1) learn to dislodge a clear barrier (a bottle) set outside the water to obtain food, (2) learn to solve a discrimination task (food versus no food) by dislodging the correct bottle, and (3) retain the ability to perform the task over a long interval. 2. Materials and methods 2.1. Study subjects and test dates Subjects consisted of nine Florida red-bellied cooters (P. nel- soni) raised in captivity from eggs collected and hatched in 2000 from three lakes (Lakes Apopka, Griffin & Woodruff) in north 0376-6357/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.beproc.2007.02.021