RESEARCH ARTICLE Cognitive Enrichment for Bottlenose Dolphins (Tursiops truncatus): Evaluation of a Novel Underwater Maze Device Fay E. Clark, 1,2 * Samuel L. Davies, 1 Andrew W. Madigan, 3 Abby J. Warner, 3 and Stan A. Kuczaj II. 4 1 Centre for Animal Welfare, Royal Veterinary College, Hawkshead Lane, Hertfordshire, United Kingdom 2 Institute of Zoology, Zoological Society of London, London, United Kingdom 3 Six Flags Discovery Kingdom, Vallejo, California 4 Department of Psychology, University of Southern Mississippi, Hattiesburg, Mississippi Cognitive enrichment is gaining popularity as a tool to enhance captive animal well‐being, but research on captive cetaceans is lacking. Dolphin cognition has been studied intensively since the 1950s, and several hundred bottlenose dolphins are housed in major zoos and aquaria worldwide, but most dolphin enrichment consists of simple floating objects. The aim of this study was to investigate whether a novel, underwater maze device (UMD) was cognitively enriching for one group of male and one group of female dolphins at Six Flags Discovery Kingdom, CA. The dolphin’s task was to navigate a rubber ball through a maze of pipes, towards an exit pipe. We also tested a modification where an edible gelatine ball fell into the pool once the UMD was solved. The UMD was provided to each group between 8 and 11 times over a 4‐week period. Male dolphins used the UMD without prior training, whereas females did not use the UMD at all. Two male dolphins solved the UMD 17 times, using a variety of problem‐solving strategies. The UMD had no significant effect on circular (repetitive) swimming patterns, but males spent significantly more time underwater when the UMD was present. Males used the UMD significantly more when it contained the rubber ball, but the gelatine ball stimulated social play. The UMD is a safe and practical device for captive dolphins. It now requires further testing on other dolphins, particularly females, to in order to examine whether the sex differences we observed are a general phenomenon. Zoo Biol. XX:XX–XX, 2013. © 2013 Wiley Periodicals Inc. Keywords: cetacean; cognitive challenge; well‐being INTRODUCTION Bottlenose dolphins (Tursiops truncatus, hereafter referred to as dolphins) are popular in zoos and aquaria, with an estimated 625 individuals living in major North American and European zoos and aquaria (SSP North American Studbook, 2012; EEP European Studbook, 2012). Aside from being popular for entertainment and education, dolphins have played an important role in the study of animal cognition since the 1950s [Pack, 2010]. Dolphins have an exceptionally large brain relative to body size [Marino, 2002] and a high level of “intelligence” compared with humans and other great apes [Marino, 2002]. “Cognitive enrichment” is “A task (or tasks) providing opportunities to use cognitive skills to solve problems and control some aspect of the environment; and whose use is associated with an increase in one or more validated indicators of positive well‐being and/or a decrease in one or more validated indicators of negative well‐being” [Clark, 2013a, p. 52]. The first part of the definition demands that the task is cognitively challenging. The animal uses cognitive skills (i.e., skills in their in‐built cognitive “tool‐ kit”) [Shettleworth, 2010] to solve problems and control some aspect of their environment. The second part of the definition requires that the task is actually enriching, by Grant sponsor: Universities Federation for Animal Welfare (UFAW); Grant sponsor: Royal Veterinary College.  Correspondence to: Fay E. Clark, Centre for Animal Welfare, Royal Veterinary College, Hawkshead Lane, Hertfordshire AL9 7TA, United Kingdom. E‐mail: fayelaineclark@hotmail.co.uk Received 20 January 2013; Revised 22 July 2013; Accepted 02 August 2013 DOI: 10.1002/zoo.21096 Published online XX Month Year in Wiley Online Library (wileyonlinelibrary.com). © 2013 Wiley Periodicals, Inc. Zoo Biology 9999 : 1–12 (2013)