Behavioural and nociceptive response in male and female spiny mice (Acomyscahirinus) upon exposure to snake odour

Predator cues (both mammalian odour or avian vocalizations) are known to el icit fear-associated responses in rodents, including analgesia. In previous studies it was reported that spiny mice fail to show fear responses when p resented with the calls of an owl. In order to test the hypothesis that thi s species (living in semiarid and rocky areas) may react to stimuli coming from reptilian predators, 40 sexually mature spiny mice (20 males, 20 femal es) were individually exposed to a small cylinder containing either fresh s awdust or snake odour. Behavioural changes (5 min before and 15 min after o dour exposure) as well as the subsequent performance in a hot-plate test (5 0 +/- 0.5 degrees C) were assessed. Results indicate that exposure to the o dour of a sympatric terrestrial predator affected both behavioural and phys iological responses of spiny mice. Upon exposure to snake odour both sexes showed significant changes in the patterns of inactivity, Sniffing, groomin g, sniffing the stimulus object (SO), withdraw reaction and in the frequenc y of somersaults. However, males increased the frequency of rearing, sniffi ng the SO, decreasing grooming more than females. No analgesic effect of od our exposure emerged; however, males showed significantly shorter latencies and higher frequencies of hindpaw licking compared to females. (C) 1999 El sevier Science B.V. All rights reserved.