Snakes - With Tentacles - That They 'See' With

"TENTACLED SNAKES SENSE FISH EDDIES"
Kathryn Knight, Inside JEB, The Journal of Experimental Biology (January 19, 2010)

"When most people think of tentacles they don't think of snakes: but not Ken Catania from Vanderbilt University. He is fascinated by the strange tentacle structures on the upper lip of tentacled snakes. 'When I first saw them I thought what the heck are those tentacles for,' recalls Catania. He is also impressd [!] by the snake's remarkable ability to outsmart fish. They startle unsuspecting victims into fleeing straight into their hungry jaws, and they also have voracious appetites, consuming large numbers of fish. 'I am absolutely amazed by this behavioural specialisation for detecting and catching fish,' says Catania. Having previously worked with another tentacled animal, the star nosed mole, Catania wondered whether the snake's tentacles could be used to detect the subtle water movements generated by fish. 'Other people have thought this before, but nobody had done any experiments to confirm the idea,' says Catania, so he set out to solve the mystery of the serpent's tentacles (p. 359)...."

A snake with tentacles. Seems redundant. And, something from a really bad science fiction B movie.

But Erpeton tentaculatus is real. In English, it's called "tentacled snake." You'd find it in ponds, rivers and streams in southeast Asia: Central and southern Thailand; southern Cambodia and Vietnam. (Fort Wayne Children's Zoo)

The JEB piece goes into a little detail on how Catania learned more about the tentacled snake. Short version: those tentacles are very, very sensitive to motion. Including eddies made by fish maneuvering near it.

And, nerves from the tentacles are wired into a part of the snake's brain that also process data from the eyes. Essentially, the snake is "seeing" with those tentacles.

What's intriguing to me is that these snakes have "have voracious appetites, consuming large numbers of fish". Snakes that I've read about generally swallow something - and then sit around for hours - days - weeks, digesting the meal.

Not tentacled snakes.

The 64-dollar question is - why does this snake need so much food? If it was a mammal or a bird, it'd be fairly obvious. A reptile, though?

More:

• "Discovery of a Water Snake That Predicts the Direction Its Prey Will Flee"
  newswise (June 18, 2009)
  • Includes diagram of snake's behavior
• "Tentacled Snake"
  Fort Wayne Children's Zoo