Further studies investigating the behavioral responses of African penguins (Spheniscus demersus) to olfactory stimuli

Most of the research into seabird olfaction has focused on procellariiforms (albatrosses and petrels); these birds are responsive to food, nest and social odors. Recently, however, we demonstrated that wild and captive African penguins (Spheniscus demersus) could detect and orient towards a food-related odor, dimethyl sulfide (DMS). Since DMS is associated with high levels of primary productivity in the ocean, we postulated that penguins could use DMS as an indicator of regions where prey is likely to be found when diving. To continue to investigate how penguins use odors while foraging, we were interested in determining whether birds were attracted to odors of their prey. We tested African penguins at a rehabilitation centre using a Y-maze that contained the scent of blended anchovy (Engraulis capensis) or a blank control and found that penguins chose randomly between these two stimuli. This suggests that penguins are not attracted to the scent of their prey. Our interpretation is that since anchovies are found at depth, penguins are unlikely to encounter the scent of their prey in the air above the ocean and thus may have little experience with this scent in the wild. Additionally, similar to our findings, many procellariiforms that hunt using DMS do not recruit to experimental deployments of the scent of their prey item at sea. In a second study we tested male and female penguins with fecal odors. In this study, we found that females avoided their own scents while males did not. The implications for the use of social odors by penguins will be discussed