Relationships between predator frontal profile size, predator-prey distance and what the prey can actually see.

<p>(A) If a predator, at a predator-prey distance , moves along a trajectory that bypasses the prey at distance , then each step of shifts the predator of toward the prey. (B) The prey does not see the whole predator frontal profile size () but only a portion , where corresponds to actual vegetation concealment that obstructs the prey's view. The predator's frontal profile size () is calculated as a product of a profile shape specific coefficient () and the square of an effective diameter (), i.e.. (C) The prey can apparently see the predator as if it was placed on a screen at a distance of one (see ‘1’ in the Figure). Consequently, the apparent size of the predator's frontal profile corresponds to apparent diameters and , for the distances (before a step) and (after the step), respectively.