Fig. 2.

Predators learn not to attack toxic conspicuous poison frogs over a series of learning trials. Learning proceeded fastest with the most toxic frog (E. parvulus evoked full learning by trial 4.33 ± 0.95 (SE); E. bilinguis, 6.33 ± 0.99; E. hahneli, 6.55 ± 0.56). A learning trial (x axis) consisted of presenting chicks with one of the brightly colored toxic frogs under a glass dome for 1 min or until chicks pecked the dome; the dome was then removed, and latency to peck the stimulus (sampling event) was recorded up until 120 seconds (y axis). Data are mean ± standard deviation (n = six chicks per treatment).