Fig. 7. Results of combined magnetic and visual impairment experiment. Each dot represents the angular difference between an individual turtle's mean heading on Day 2 versus Day 1. Turtles wearing frosted goggles and fitted with brass bars maintained an orientation direction from Day 1 to Day 2, while those bearing frosted goggles and magnets did not do so. (A) Brass bars + frosted goggles; mean angle=31°, r=0.69, P<0.01 V-test, 95% confidence interval ±41°; (B) South-up magnets + frosted goggles; mean angle=196°, r=0.65, NS V-test; (C) North-up magnets + frosted goggles; mean angle=110°, r=0.37, NS V-test. See text for statistical comparison of distributions. NS, not significant.

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