Into The Jaws of Death

I came across an article on the tentacled snake, Erpeton tentaculatum, in BBC Knowledge magazine and was amazed by the feeding behavior and ambush mechanisms of this aquatic snake.  The tentacled snake, distinguished by its pair of oval shaped projections at the tip of its mouth, is an aquatic specialist in many ways, but what is most interesting is its strategy to ‘spook its prey into its mouth’ (BBC Knowledge magazine, 88).  This ambush hunter is a freshwater snake that is most commonly found in Thailand and Kampuchea in shallow, murky lagoons or creeks and belongs to the family colubridae (rear fanged snakes).  The tentacled snake differs from other aquatic snakes in that (1) it does not catch prey while effectively moving through the water (2) nor does it sweep an open mouth back and forth waiting to come to close proximity to its prey (Smith, Povel and Kardong 2002: 234), making this species unique on its own.  Their primary sources of diet are small fishes.

snake 1

Picture courtesy of Hanneskei

http://www.geocities.com/hanneskei/Snakes.html

The tentacled snake tricks its prey to an easy meal, and one of its brilliant attribute is its ability to predict its prey’s movement, turning the fish defense mechanism into its mode of striking.  The snake lies in ambush by settling in a position, wrapping its tail around an object like a submerged branch, which helps to hold its body firm.  Its tentacles aids in breaking up the snake’s shape, and together with its non-distinct colors, stiff body and slow movements, these add as an important ambush element and behavior, to avoid observation and detection by both predators and preys (Smith, Povel and Kardong 2002: 239).  These are important attributes, which is important to its feeding behavior as well, with its strategy on the ‘element of surprise’.

snake 2

Illustration diagrams how the tentacled snake uses a body fake to trigger fishes’ reflexive C-start response causing them to swim directly toward the snake’s mouth. (Credit: Ken Catania)

(http://www.sciencedaily.com/releases/2009/06/090618170024.htm)

The above diagram is a general overview of how the snake attacks and strikes its prey.  The C-start is the preprogrammed escape response in fish (http://www.the-scientist.com/blog/display/55802/), creating an obvious route that the snake exploits.  As shown, the fish simply swims to its doom, the moment its escape mechanism is activated. How does this happen?  Firstly, the tentacled snake exploits the defense of fishes by positioning its neck in a J-position.  It is fascinating to note how this effective technique works at such precision and swiftness.  Combining both its ambush elements and its striking position, the snake waits patiently for a fish to swim into the area near the hook of the “J”.  At that very moment, the snake would twitch its body, activating the C-start of the fish, causing the fish to swim to its death and into the jaws of the snake.  Once the C-start is activated, the fish will not be able to turn back (http://www.sciencedaily.com/releases/2009/06/090618170024.htm) and it is amazing how the tentacled snake has developed the ability of predicting the future behavior of its prey, turning its escape response to its advantage.  Despite being mildly venomous, the venom is enough to immobilize the fish, which further confirms a good meal (http://zooatlanta.com/animals_snakes_wor.htm).

Tentacled snake in action on youtube

Referencing

Smith, Tamara L., Povel, G. David E. and Kardong, Kenneth V. (2002) ‘Predatory strike of the tentacled snake (Erpeton tentaculatum)’ The Zoological society of London. Vol. 256. Pp. 233 – 242.

BBC Knowledge (Asia ed) Vol 2 issue 2, ‘Strange but true’. Bristol Magazine Ltd 2009. Pp. 88

Vanderbilt University (2009, July 14). ‘Water Snake Startles Fish So They Flee Into Its Jaws.’ ScienceDaily. Retrieved April 6, 2010, from (http://www.sciencedaily.com/releases/2009/06/090618170024.htm)

Website sources:

Zoo Atlanta ‘Snake of the world of reptiles’ – Retrieved April 6, 2010, from(http://zooatlanta.com/animals_snakes_wor.htm).

Images and video:

‘Tentacled snake’ by Reider, Stephanie

URL: (http://whozoo.org/Intro2002/StephReder/SJR_Tentacledsnake.htm), image courtesy of Hanneskei URL:http://www.geocities.com/hanneskei/Snakes.html, retrieved April 6th, 2010

‘Water snake startles fish so they flee into its jaw’ by

Vanderbilt University (2009, July 14). ScienceDaily. Retrieved April 6, 2010, from (http://www.sciencedaily.com/releases/2009/06/090618170024.htm), image credited to Ken Catania

‘Tentacled snake in action’ by Kenneth Catania, Vanderbilt University youtube channel, 19 June, 2009. URL: http://www.youtube.com/watch?v=urBp2X5mBmQ (accessed on 6th April 2010).

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