Table 1.

The ΔAICc for models explaining per capita risk for virtual prey

Explanatory variableΔAICcdf
Position05
Number of near neighbors6.62
Whether solitary or not13.52
Total group size18.22
Prey with attraction29.62
Prey type31.23
Prey appears social37.23
Null model (no explanatory variables)49.71
  • Each prey at the time of each attack was included in the data, and the response variable was whether each prey was the attacked prey (one) or not (zero). Different models have different explanatory variables. The null model has no explanatory variable. The prey-type models use which of the three prey types a prey is (asocial, leader, and follower) or reclassifications of these: attraction or not (follower type vs. the asocial and leader types as a single category) and social or not (the follower and leader types as a single category vs. the asocial type). The remaining models consider the behavior of each prey at the moment of attack. The group size model uses the total number of prey in a prey’s group as the explanatory variable, the solitary model uses a binary explanatory variable of whether each prey was solitary or not, and the near-neighbors model uses the number of prey within the threshold distance around each prey as the explanatory. Only the prey position model considers the relative spatial location within a group for each prey based on the heading difference and bearing of other prey in addition to whether prey were solitary.