The ability of 6 captive aye-ayes (Daubentonia madagascariensis) to discriminate scents from conspecifics of different age-sex classes was tested. The animals were presented with either unscented logs or logs that had been placed in: (1) their own cage, (2) the cages of adult males or (3) the cages of adult females with female offspring. Responses to the logs, measured by approaching, proximity, tapping, gnawing, sniffing, scent marking and vocalizations, were recorded for 30 min following presentation. Logs from females with offspring provoked the highest responses, and immature aye-ayes investigated logs more than adults of either sex. These results suggest that, as in many other prosimians, olfaction plays an important role in the communication systems of aye-ayes.