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Figure 2 | BMC Ecology

Figure 2

From: Rodents in open space adjust their behavioral response to the different risk levels during barn-owl attack

Figure 2

i. Rank order of the speed of locomotion of individual spiny mice in each of the four phases of barn-owl attack. The speed was calculated for each rodent by dividing the distance it traveled in each phase by the locomoting time at that phase. The speeds of all spiny mice in all four phases were then pooled and ranked from low to high and are depicted in this figure with a different symbol for each phase. As shown, individual spiny mice at the same phase (same symbols) aggregated to the same range, indicating that each phase has a typical differential speed. Specifically, spiny mice traveled at low speed during Pre-appearance (), they increased speed during Appearance (□), and further increased it during Attack (). During Post-attack (▲) they attained a speed that was higher than Appearance and lower than during Attack. ii. Rank order of the speed of locomotion of individual voles for each of the four phases of barn-owl attack. Data were calculated and depicted as explained above for spiny mice. As shown, the speed during Pre-appearance (), either increased or decreased during Appearance (□), and moved further in one of these opposite directions during Attack (), to zero in voles that froze (left ranks) and voles that fled (in the right third of the graph). During Post-attack (▲) most voles traveled at a relatively high speed regardless of their previous behavior (freeze or flee). iii. The mean (± SEM) in spiny mice during the four phases of owl attack. As shown, the control group (, dotted line) maintained the same speed throughout all phases, whereas spiny mice that were exposed to owls (■, solid line) started at the control level during Pre-appearance, increased the speed during Appearance, further increased it during Attack, and slightly decreased during Post attack. There was significant difference between control and owl groups (F1,21 = 388.6; p < 0.001), between phases (F3,36 = 43.7; p < 0.001) and significant interaction of group × phase (F3,63 = 39.4; p < 0.001). Further comparisons in Tukey test are indicated by * for difference compared with control and + for difference compared with the previous phase.iv. The mean (± SEM) speed in voles during the four phases of owl attack. Three groups are shown: i) controls, not exposed to owls (, dotted line); ii) voles that fled during owl attack (■, solid line); and iii) voles that displayed freeze response during owl attack (▲, dashed line). As shown, the control group maintained the same speed throughout all phases, whereas voles that were exposed to owls started at the control level during Pre-appearance, and dichotomized to freeze (speed = 0) and flee during Attack. Both these groups revealed the same speed during Post-attack. Indeed, there was significant difference between groups (F2,16 = 8.6; p = 0.002), between phases (F3,48 = 4.8; p = 0.004), and in the interaction of group × phase (F6,48 = 5.9; p < 0.001). Further Tukey comparisons are depicted by * for difference compared with control level; for difference compared with the respective phase in voles that froze; # for difference between Attack phase in freeze group compared with Appearance, Attack and Post-attack in the voles that fled.

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