Figure 1—figure supplement 2—source data 1.

Figure 1—figure supplement 2—source data 1.

(A) Colors are histograms of coordinates for prey chosen at hunt initiation, gray are all prey records [chosen + ignored. Note: XY records passing a threshold length and velocity that remain unpaired after prey reconstruction are assigned the Z-coordinate of the tank ceiling because live paramecia show anti-gravitaxis (Roberts 2010); we always noted that a subset of prey gather at the ceiling and never noticed coagulation of prey on the ground unless dead; results are very similar to those shown if ceiling assigned prey are not counted]. (B) Histograms showing the distribution of spherical velocities for chosen prey do not reveal a bias in magnitude or direction. (C) Count plots of distance rank for selected prey (0 = closest). (D) We virtually displaced fish coordinates at hunt initiation bouts into randomly recorded paramecium environments and asked whether the closest prey item in that environment shared azimuth and altitude features with prey that fish actually chose. Histograms of the closest prey in random prey environments and prey environments in which initiation actually occurred are plotted in red (for random condition, fish orientation and position at hunt initiation is projected into a different time during the experiment; left panel). Blue (az) and yellow (alt) histograms are chosen prey histograms from (A) for comparison. The closest prey item in a random environment does not show the same distribution as selected prey in (A), indicating that the closest prey does not necessarily have to share the altitude and azimuth features of chosen prey. This suggests that somewhat specific prey features are preferred for entry into the hunting state, although transition probabilities governing hunting mode entry are also at play (Johnson et al., 2019; Mearns et al., 2019).

Figure 1—figure supplement 2—source data 1.