Prey snapping and visual distance estimation in Texas horned lizards, Phrynosoma cornutum
| Autor: | Joachim Ostheim, Matthias Ott, Wade C. Sherbrooke |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
genetic structures
Physiology media_common.quotation_subject Video Recording Aquatic Science Phrynosoma cornutum Predation Tongue medicine Contrast (vision) Animals Molecular Biology Ecology Evolution Behavior and Systematics media_common Depth Perception Monocular biology business.industry Arizona Accommodation Ocular Lizards Anatomy Feeding Behavior biology.organism_classification eye diseases Biomechanical Phenomena Visual distance medicine.anatomical_structure Insect Science Animal Science and Zoology sense organs Depth perception business Accommodation |
| Zdroj: | The Journal of experimental biology. 207(Pt 17) |
| ISSN: | 0022-0949 |
| Popis: | SUMMARY Captive Texas horned lizards were high-speed videotaped while feeding on ants in order to study the role of vision in facilitating tongue-protrusion capture of prey. Analysis of tongue movements revealed that prey snapping in these lizards is not a typical fixed-action pattern. By contrast, it is variable in performance and duration. Lizards adjusted head and tongue direction during the strike, within a few milliseconds, in response to movements of the prey. The duration of a typical tongue strike was 100-150 ms. The strike duration was prolonged after ophthalmic lenses were placed in front of one or both eyes. These lenses were used to investigate whether horned lizards use accommodation to judge prey distance. Focal changes of negatively powered ophthalmic lenses (employed monocularly) induced a clear underestimation of prey distance by the lizards, confirming the hypothesized expectation that accommodation is used for depth perception. The effect of the lenses was different in the two animals tested with monocular restriction. This, together with the lack of difference in responses by the lizards when untreated and when both eyes were lens covered (binocular treatment of equal power, -9 D), illustrates that horned lizards also use other visual parameters for depth perception. |
| Databáze: | OpenAIRE |
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