Visual Tracking: Hot Pursuit with Tiny Eyes Eric J. Warrant  Current Biology  Volume 27, Issue 6, Pages R234-R237 (March 2017) DOI: 10.1016/j.cub.2017.02.032 Copyright © 2017 Elsevier Ltd Terms and Conditions

Figure 1 The North American robber fly Holcocephala fusca. This tiny fly (A) is an agile predator whose compound eyes (B) are large relative to body size and flattened frontally to create a fovea of 20–30 huge facets (circled in B). This fovea is used to fixate, track and finally intercept flying prey during a high-speed aerial pursuit. Images courtesy of the photographer Thomas Shahan (via a Creative Commons Attribution 2.0 Generic License). Current Biology 2017 27, R234-R237DOI: (10.1016/j.cub.2017.02.032) Copyright © 2017 Elsevier Ltd Terms and Conditions

Figure 2 The ‘constant bearing angle’ model of visual interception. Both in the robber fly Holcocephala fusca (A) and in humans (B, human head and shoulders seen in top view), a constant visual bearing (θ in B) is maintained throughout the interception so that the vectors joining the animal with its target (‘range vectors’) are always parallel, ensuring a successful interception even if the target changes its velocity or alters its direction. Panel A constructed from images provided by Trevor Wardill and colleagues; panel B re-drawn from [8]. Current Biology 2017 27, R234-R237DOI: (10.1016/j.cub.2017.02.032) Copyright © 2017 Elsevier Ltd Terms and Conditions