This overdue post was inspired by the symposium ‘‘New Frontiers from Marine Snakes to Marine Ecosystems’’ presented at the annual meeting of the Society for Integrative and Comparative Biology, January 3–7, 2012 at Charleston, South Carolina, and featured in a special issue of the journal of the same name.
Head of a Pelagic Sea Snake, Pelamis platura |
The range of the Pelagic Sea Snake, which is the world's widest ranging species of snake |
Artist's rendition of "float-and-wait" foraging.
I was unable to find a photograph of this behavior.
If you know of one, please let me know.
Digital painting by Stuart Jackson-Carter; www.sjcillustration.com
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Crustacean epibionts from Pelagic Sea Snakes |
In order to keep this menagerie under control, Pelagic Sea Snakes shed frequently. On average, a Pelagic Sea Snake will shed its skin once every three weeks, whereas most other snakes go for one to two months between sheds. Additionally, while in most snakes the frequency of shedding decreases with age, it remains frequent into adulthood in Pelagic Sea Snakes. Because the open ocean is devoid of surfaces against which to rub to facilitate shedding, Pelagic Sea Snakes use a behavior known as "knotting" to initiate the process and to remove the shed skin and any associated epibionts. You can see a good example of knotting behavior in this video of a captive Pelagic Sea Snake:
Pelamis platurus never leave the water and cannot move on land. Most that land on beaches die. |
Why do so many animals live on Pelagic Sea Snakes? One explanation may be the protection associated with settling upon one of the world's most venomous serpents. Pelagic Sea Snakes are not eaten by most seabirds or fishes (although naïve Atlantic fishes will consume them, and sometimes die from it) and so neither are their epibionts. Perhaps natural selection has favored the crabs, barnacles, and tunicates that live on sea snakes over those that land on more palatable substrates. Furthermore, the complex interplay among various members of the sea snake epibiont community may allow more species to coexist there. For instance, predatory epibionts such as larval crabs may benefit the sea snakes by controlling populations of other, more detrimental epibionts, such as barnacles, which probably slow or block the update of oxygen by the snake's skin during long dives.
Sea snakes are among the most amazing of serpents, and Pelagic Sea Snakes are among the most amazing of sea snakes. From their saffron bellies to their lung, used to control buoyancy, to their roles as substrates for unique ecosystems, these snakes might just be the most incredible snakes out there.
Sea snakes are among the most amazing of serpents, and Pelagic Sea Snakes are among the most amazing of sea snakes. From their saffron bellies to their lung, used to control buoyancy, to their roles as substrates for unique ecosystems, these snakes might just be the most incredible snakes out there.
ACKNOWLEDGMENTS
Thanks to William Flaxington, Hung-Jou Chen, Chayajit, and Stuart Jackson-Carter for their photos and digital illustrations, and to Joe Pfaller for answering my questions about sea snake epibionts.
REFERENCES
Brischoux, F. & H. B. Lillywhite (2011). Light-and flotsam-dependent ‘float-and-wait’foraging by pelagic sea snakes (Pelamis platurus). Marine Biology 158:2343-2347 <link>
Castro, J. J., J. A. Santiago & A. T. Santana-Ortega (2002). A general theory on fish aggregation to floating objects: An alternative to the meeting point hypothesis. Reviews in Fish Biology and Fisheries. 11:255-277 <link>
Graham, J. B. (1974). Aquatic respiration in the sea snake Pelamis platurus. Respiration Physiology 21, 1-7 <link>
Graham, J. B. (1974). Aquatic respiration in the sea snake Pelamis platurus. Respiration Physiology 21, 1-7 <link>
Greene, H. W. (1997) Snakes: The Evolution of Mystery in Nature. Berkeley: University of California Press <link>
Pfaller, J. B., M. G. Frick, F. Brischoux, C. M. Sheehy, and H. B. Lillywhite. 2012. Marine snake epibiosis: a review and first report of decapods associated with Pelamis platurus. Integrative and Comparative Biology 52:296-310 <link>
Rubinoff, I. & C. Kropach (1970). Differential reactions of Atlantic and Pacific predators to sea snakes. Nature 228, 1288-1290 <link>
Zann LP, Cuffey RJ, Kropach C. 1975. Fouling organisms and parasites associated with the skin of sea snakes. In: Dunson WA, editor. The biology of sea snakes. Baltimore: University Park Press. p. 251–65
Rubinoff, I. & C. Kropach (1970). Differential reactions of Atlantic and Pacific predators to sea snakes. Nature 228, 1288-1290 <link>
Zann LP, Cuffey RJ, Kropach C. 1975. Fouling organisms and parasites associated with the skin of sea snakes. In: Dunson WA, editor. The biology of sea snakes. Baltimore: University Park Press. p. 251–65
POSTSCRIPT
Cetacean photographer Eduardo Lugo captured this image of a Pelagic Sea Snake being pushed up out of the water by a dolphin, almost as if it was riding on its back:
Perhaps Pelamis is heading towards a lifestyle as a dolphin epibiont? Lugo says they were swimming with the dolphins from a Wildlife Connection ecotour boat when the dolphins decided to play with the snake.
Life is Short, but Snakes are Long by Andrew M. Durso is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.