The New York Times,
February 8, 2005Link
In the world of competitive eating, it's time to crown a new champion.
Even the fastest human eaters need a few seconds to consume a piece of food. The current record for devouring hard-boiled eggs, for example, is 65 eggs in 6 minutes 40 seconds, by Sonya Thomas of Alexandria, Va. That works out to about six seconds an egg.
But according to a report last week in the journal Nature, Ms. Thomas and her fellow record-holders must step aside to make room for the star-nosed mole, a bizarre creature that lives in wetlands in the Eastern United States.
Researchers at Vanderbilt University have found that the star-nosed mole can eat 10 mouthful-size chunks of earthworm, one at a time, in 2.3 seconds, or 0.23 second a chunk. That is over 26 times as fast as Ms. Thomas in her record-shattering performance. In fact, it is the fastest eating ever measured in any mammal.
''It's a fascinating study; it's really unbelievable,'' said Dr. Kurt Schwenk, an evolutionary biologist at the University of Connecticut, who was not involved in the research.
The star-nosed mole (Condylura cristata) has perplexed biologists for decades. For the most part it looks like an ordinary mole, except for its nose, which sprouts 22 fleshy rays that squirm like miniature fingers.
Studies carried out by a Vanderbilt neuroscientist, Dr. Kenneth C. Catania, have found that the star is an exquisitely sensitive sensory device. It is covered by 25,000 sensory receptors and contains 100,000 large nerve fibers --six times as many as an entire human hand. A large part of the star-nosed mole's brain is dedicated to using the signals it detects to create a sort of touch-portrait of its surroundings.
To understand how the moles actually use their stars, Dr. Catania built an artificial tunnel with a glass bottom, through which he could film the animals searching for food. When he and a research assistant, Fiona E. Remple, began reviewing the films, he could not believe that the moles were feeding so quickly.
''It was so fast, I thought it might not be correct,'' he said. ''I had to recalibrate the camera.''
The films showed that a mole swept its star back and forth, its rays touching the glass 13 times a second. As soon as it encountered a piece of food, the mole probed it with a pair of particularly sensitive rays just below its nostrils. If the mole decided to eat the object, the two rays moved apart, so that it could grab the food with its tweezer-shaped front teeth.
This entire sequence required as little as a fifth of a second. Dr. Catania could find no other mammal that took less than a full second to handle food.
''I don't know of anything that comes close to this,'' he said.
To squeeze so much activity into so little time, star-nosed moles have pushed the nervous system to its speed limit.
''You couldn't go much faster,'' Dr. Catania said.
The new results support the idea that the star evolved as an adaptation for super-efficient feeding. It emerged, Dr. Catania suggests, when the ancestors of star-nosed moles first moved into wetlands. Compared with dry soil, wetlands are loaded with small insect larvae, which could become a good source of energy for a mole, but only if the animal used a very small amount of energy to find them.
Other moles have touch-sensitive receptors around their nose, but Dr. Catania proposes that the ancestors of star-nosed moles evolved a much denser array, making them more sensitive to small prey they encounter in their tunnels.
As for the origins of the strange star, Dr. Catania thinks the relatives of star-nosed moles may offer a clue. There are a couple of other species that have proto-stars forming on the tip of the nose, he says.
These proto-noses look identical to the true star during an early stage in the development of the star-nosed mole embryo.
Star-nosed moles may have simply evolved a more elaborate version of a proto-star, thereby increasing the range of their search.
If this star provided such a benefit, it is intriguing that only one species of mole evolved it. Dr. Catania suspects that the wetland home of star-nosed moles is the reason. Unlike the star-nosed moles that live in damp, soft earth, other mole species live in dry soil. In such a habitat, a delicate, highly sensitive star would have been badly damaged.
As star-nosed moles became faster feeders, they could speed their rate of intake dramatically by shaving off tiny fractions of a second from their eating time. Dr. Catania believes one way they saved time was by evolving a more efficient brain.
All mammal brains represent the information that comes from touch-sensitive maps of the body. Moles have two maps of their nose. Star-nosed moles, on the other hand, have three.
Dr. Catania suspects that these multiple map divvy up the work involved in analyzing signals coming from the stara procedure that computer engineers call parallel processing.
That might give you greater efficiency, says Dr. Catania.
Dr. Catania now plans to study the brain circuitry that allows star-nosed moles to feed so quickly.
''They've been a gold mine of discovery for me since the first time I looked at them,'' he said, ''but I think there's still a lot more to do.''
He is not the only person who is impressed by the star-nosed mole, however.
''I would love to see one of these moles in action,'' said George Shea, chairman of the International Federation of Competitive Eating. ''It makes one wonder if there's an opportunity for a cross-species contest. I think there'd be interest in both the human and mole populations.''
Copyright 2005 The New York Times Company