Figure 2.

(a) Mean (±s.e.) proportion of time spent grazing, scanning and walking (top, middle and bottom traces, respectively) as a function of group size. The inset indicates the standard deviation among individuals of the proportion of time spent scanning for each group size. (b) Individual sheep scanning profiles. The lines link the proportion of time spent scanning for each individual tested in each group size. The inset indicates the mean (+s.e.) per cent difference in scanning activity for groups of 2, 3, 4 and 8 compared with groups of 16 sheep.