Fig. 3

The responses of fallow bucks to natural groans and modified groans with raised formant frequencies. Pairs of points joined by lines represent the response of an individual buck. Bucks looked toward the speaker for less time (b) and were more likely to approach the speaker (d) in response to groans with raised formant frequencies than natural groans. There was no consistent difference in response in either the latency to look towards the speaker (a), or the latency to begin moving (c) between groan types (see Results for statistics)