I studied play behaviors of California sea lion pups in the Gulf of California (GoC), Mexico during the 2004, 2005, and 2006 breeding seasons. The aim of this study was to evaluate the potential impacts of human-related activities on population status. I compared play behavior from three islands exhibiting distinct population trends along a latitudinal gradient (San Jorge (north), Granito (central), and Los Islotes (south)). I first examined particular aspects of play behavior, including time budgets for male and female pups, the percentage of play of active behaviors, and pup condition in relation to observed play behaviors. I then examined the relationship between observed anthropogenic impacts at each site and pup play behavior. An analyses of time activity budget revealed pups spend approximately 6% (N=672; SD=17) of time engaged in play behavior. Observed human impacts surrounding San Jorge, Granito, and Los Islotes differed significantly (F (2, 1412) = 2040, p = ≤ 0.05). These impacts did not appear to influence play behavior. Of active (vs. inactive) pup behaviors, the proportion of time spent in play accounted for 5% at San Jorge, 14% at Granito, and 8% at Los Islotes in 2004. In 2005 play accounted for 13% of time in active behaviors at San Jorge, 9% at Granito, and 6% at Los Islotes. No significant differences across islands were found for any year. A comparison of means showed no significance between gender and observed play behaviors (F (1, 224) = 2.60, p = ≤ 0.05). Additionally, for all sites, no significant relationship between pup condition and percent of time engaged in play behavior was shown. These results highlight the importance of future research on the relationship between play behavior and population dynamics. Understanding relationships between human activities and California sea lions in the GoC is important for implementing successful conservation strategies.

Keywords: California sea lion, Zalophus californianus, conservation, play, behavior.