Easy Lunch for Fish-Tricking Snake

June 24, 2009 — -- Kenneth Catania has a new weirdo to add to his collection -- a fish-eating snake that is so clever it can trick its prey into swimming right into its mouth.

Catania is a neuroscientist at Vanderbilt University who is becoming a bit of a legend in his field because he specializes in figuring out why some animals are just so strange. Like the star-nosed mole that is ugly enough to scare its own mother.

Why pay so much attention to the strangest of animals?

"What makes these animals so strange is their extreme specialization, and for that very reason, there is a great deal that we can learn from studying them," Catania says.

There's a reason why the hamster-sized star nose mole has a snout with 11 pairs of pink appendages that form a fleshy star. The mole, rarely seen by humans because it lives in marshes, uses its ugly nose to feel differences in textures down to the microscopic level.

What Can Strange Animals Teach Us About Ourselves?

Catania has shown that the mole's nose has 25,000 microscopic sensor receptors and 100,000 nerve fibers that run from the nose to the brain, more than six times the number that connect the human hand and brain. That apparently is why the nearly blind rodent approaches the theoretical maximum speed for locating and consuming food, according to his research.

Why should anyone care? Because there are striking similarities between the mole's sensitive nose and the human visual system, he said, so if we learn a lot about the star-nosed mole we may learn something more about ourselves.

But Catania, who received the MacArthur "genius" award in 2006 for his fascination and exploration of nature's oddballs, has more recently focused his attention on the amazing tentacled snake of South East Asia. It's the only snake with two short tentacles on its nose, and he wanted to know why they were there.

Using a high speed video camera (he is also an accomplished photographer) Catania documented a talent he has seen in no other animals. He conducted 120 trials with four different snakes. In 78 percent of the time, the prey turned and swam right into the snake's mouth instead of fleeing.

Snake Anticipates What the Fish Will Do

And when the snake strikes, it doesn't aim for where the fish is. Surprisingly, it aims for where will be just after the attack began.

Somehow, the snake anticipates what the fish is going to do, according to Catania's research, published in the online edition of the Proceedings of the National Academy of Science.

All that happens in a few hundredths of a second, too quickly for the human eye to capture, and it's not the way the final encounter between a snake and a fish usually works. Many fish are equipped with a remarkable and well studied talent that allows them to make a speedy exit when a predator appears.

Called a "C-start" by biologists, many fish can bend their bodies into the shape of the letter C, facing away from the predator. When the time is right, the fish darts away in an escape response that has been measured at a few thousandths of a second.

The snake wins, because from the get-go, the snake is in charge.

Catania Known for Research and Humor

Catania lowered a hydrophone into the aquarium because fish ears sense which way the predator's sound waves are coming from, thus allowing the fish to prepare for a speedy departure in the opposite direction.

But the snake, in this case, produces sound waves from its body, not its head, and the waves come from the opposite side of the fish, thus confusing the fish about which way to depart. It's a nasty trick, but it's useful for the snake.

It may all sound like a lot of fun, but that, too, is right down Catania's alley. He may be as well known on the Vanderbilt campus for his sense of humor as he is for his research. He keeps a skull with a spear through it handy, no doubt to remind students to pay attention.

Back in his undergrad days at the University of Maryland, Catania and a carload of fellow students were pulled over by what was later described as a "surly" Maryland trooper.

The cop started asking questions about their field of neuroscience, provoking a fierce disagreement among the students over some issue that could only be meaningful to eggheads.

It turned out that the encounter was a hoax. Catania had talked a college chum into posing as the trooper in a practical joke that reportedly took a year to plan.