Metamorphosis of behavior in the bullfrog (Rana catesbeiana)

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Abstract
This study describes the development of different spontaneous and elicited behaviors of frogs and their relationship to morphological, physiological, and econological changes of metamorphosis. Tadpoles were studied at all stages of development from STage XVIII, the onset of metamorphosis, to Stage XXV, when metamorphosis of the froglets is complete. Behaviors examined included development of forelimb postural support, postural responses to vestibular stimulation, the hindlimb withdrawal reflex, the corneal reflex, ocular mobility, and habital preference. Results showed that these behaviros differ markedly in their timing and rate of maturation. Forelimb postural support and postural responses to vestibular stimulation improved gradully between Stagez XX and XXV. In contrast, the threshold of the hindlimb withdrawal reflex remained essentially unchanged until Stage XXV, when it increased suddenly and dramatically. The corneal reflex appeared suddenly at Stage XXI with a threshold similar to that of juvenile forgs. The ability to move the eyes in response to visual or vestibulaar stimulation was pronounced it tadpoles, but gradually declined between Stage XIII and Stage XXV, so that froglets showed almost no ocular mobility. The preference of metamoprphosing frogs for deep water, shallow water, shoreline, or land were examined in an aquarium during a 24‐hr observation period using time‐lapse videotape recordings. Results showed that tappoles spent progressively less time in deep water and shallow water as metamorphosis proceeded. Preference for land emerged suddenly at Stage XXII and remainhed high thereafter. There were no stage‐related differences in preferences for the shoreline.