Tuesday, June 5, 2012

Neotropical Snakes That Span Gaps


Imantodes cenchoa

 Arboreal snakes can extend their bodies up to 50% of their length to bridge a gap between branches or perches under laboratory conditions. Morphological adaptations associated with this including lateral compression of the body, elongation of the tail, widening of ventral scales, forward-facing eyes that also can be aimed downward, and reduction in relative mass and the most agile species possess rigid muscles and tight skin, providing for more controlled movements and cantilevering. Specialized behaviors also play an adaptive role, but have been studied less because of the logistic difficulties of accessing and working in arboreal habitats.  A recent examination of cantilevering by Ray (2012) in adult snakes from Omar Torrijos National Park in CoclĂ© Province, Panama used: Dipsas sp., Imantodes cenchoa, Oxybelis brevirostris, Sibon argus and S. annulatus. Also included were several less abundant species that were tested opportunistically and included I. inornatus, Leptodeira septentrionalis, and S. nebulatus. Species of Imantodes and Sibon exhibited the greatest ability to bridge distances in the experiments and they show the more highly adapted morphologically for arboreal habits. These species able to exploit smaller twigs, which facilitates movement between the ends of branches and subsequent cantilevering, presumably allowing these species to exploit food resources other snakes have difficulty reaching.

Citation
Ray, J.M. 2012. Bridging the gap: interspecific differences in cantilevering ability in a Neotropical arboreal snake assemblage. South American Journal of Herpetology 7:35-40.

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