1. Swimming paths of Freja in no fish (A) and fish trials (B) with no eyecups and when blindfolded (with eyecups).
Swimming paths of Freja in no fish (A) and fish trials (B) with no eyecups and when blindfolded (with eyecups). The hatched circle is the area of fish release. The three black dots show the hydrophone array (H), and the two black squares represent the two underwater video cameras (U). The arbitrary reference point (X) is 1.5 m behind the front edge of the pontoon. White dots on the swimming paths indicate 5 m intervals and the 30 m, 20 m and 10 m points show distance to the reference. The content of the grey frame in B is shown enlarged in C with the swimming paths of Freja (thin lines) and the fish prey (thick lines). Swimming paths of Freja and prey from the same trial are marked with the same grey shade. Black circles indicate the position of the fish catch or catch attempt.
Ursula K. Verfuß et al. J Exp Biol 2009;212:
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