Comparing albino and hooded Wistar rats of both sexes on a range of behavioral and learning tasks

Albino and hooded Wistar rats of both sexes were compared on several behavi oral measures and learning tasks. Overall the most marked behavioral differ ences produced by albinism were reduced metabolism-as indicated by food and water consumption, defecation, and direct calorimetric measures of respira tory quotient and energy expenditure-and emotionality-as displayed in an op en field, plus maze, and radial maze. No sex or strain differences were fou nd for neophobia or preference for saccharin, but less tolerance of bitter (quinine) was shown by hooded rats and less tolerance of sour (HCl) by male s. In learning tasks in restricted environments, comparable acquisition acr oss groups was found for instrumental conditioning, appetitive classical co nditioning, and taste aversion learning. However, hooded rats showed greate r latent inhibition with auditory stimuli and more sensitivity to contextua l cues, both in nausea-based conditioning and in the radial maze. Overall t he results suggest that careful choice of rat strain is required in behavio ral experiments where environmental factors are critical.