The present study investigated spatial memory in domestic dogs (Canis familiaris) through the use of a radial arm maze. The study consisted of a total of three separate experiments. In the first two experiments, the ability of the dogs to successfully remember previously unentered arms was evaluated. The third experiment was similar to the first two, but also examined the nature of the serial position effect. Performance in all three experiments was better than expected solely by random choices. Dogs showed a much better memory for spatial locations presented earlier in a spatial list compared with those presented in the middle. Based on the present results, we suggest that the radial arm maze assesses canine spatial memory and that dogs sh...