Portal de Periódicos da CAPES

The Sun Compass of Fowler's Toad, Bufo Woodhousei Fowleri

1967; Brill; Volume: 30; Issue: 1 Linguagem: Inglês

10.1163/156853968x00162

1568-539X

Hobart F. Landreth, Denzel E. Ferguson,

Animal and Plant Science Education

[Apparatus and techniques were developed to test bufonid's use of celestial cues to find preferred directions in controlled experiments. Toads were trained to select an escape direction relative to a sun lamp and were found to maintain a course at the same angle to the light cue when the apparatus was rotated, the light moved, when tested outdoors under the sun, and if various lamps (e.g., bright incandescent, dim incandescent, infrared, and red flood) were substituted for the sun lamp. Reference objects, learned muscular movements, sounds, and odors were eliminated as possible orientational cues in this investigation. Toads could not orient to the learned direction when the light cue was obscured and the shadows were evenly distributed. B. w. f owleri possess a clocking mechanism and are able to compensate for the apparent 15° per hour movement of the cue throughout a diel cycle. The azimuth of the cue seems to be more important than the altitude to toads. Trained animals can be diverted from a trained direction by conspecific calls after injections of sex hormones. Celestial orientation is considered a basic orientational mechanism and apparently functions in conjunction with other mechanisms in the natural environment of toads., Apparatus and techniques were developed to test bufonid's use of celestial cues to find preferred directions in controlled experiments. Toads were trained to select an escape direction relative to a sun lamp and were found to maintain a course at the same angle to the light cue when the apparatus was rotated, the light moved, when tested outdoors under the sun, and if various lamps (e.g., bright incandescent, dim incandescent, infrared, and red flood) were substituted for the sun lamp. Reference objects, learned muscular movements, sounds, and odors were eliminated as possible orientational cues in this investigation. Toads could not orient to the learned direction when the light cue was obscured and the shadows were evenly distributed. B. w. f owleri possess a clocking mechanism and are able to compensate for the apparent 15° per hour movement of the cue throughout a diel cycle. The azimuth of the cue seems to be more important than the altitude to toads. Trained animals can be diverted from a trained direction by conspecific calls after injections of sex hormones. Celestial orientation is considered a basic orientational mechanism and apparently functions in conjunction with other mechanisms in the natural environment of toads.]