Archives of The Cold Blooded News

The Newsletter of the Colorado Herpetological Society

Volume 31, Number 9;   September, 2004

Underachieving Snakes Helped by New Teaching Method

by Tamar Simon

David Holtzman, a neuroscientist at the University of Rochester, conducts research into reptile intelligence. He found that decades-old studies that rated snakes as less intelligent than mice and rats weren't fair. Snakes just don't encounter anything like a maze in nature.

"Studies that said snakes couldn't learn well put snakes through mazes, which they didn't learn as well as mice or rats," Holtzman says. "But that's asking the [snake] to do something...not natural to do." So Holtzman and his research team designed a "natural" snake task to test how well snakes could learn spatial skills.

They took 24 corn snakes and put them, each by themselves, into a two-meter wide plastic tub with a one-meter high rim. The tub's sides were too high for the snakes to climb out, but there were eight holes cut out in the bottom -- one of which led to a hidden shelter. The escape hole was land-marked with a brightly-colored card mounted on the tub's walls. Tape was also placed on the floor to provide a tactile pointer. The team then "motivated" the nocturnal snakes to find the shelter by placing the tub -- already uncomfortable for snakes, which don't like being in large open spaces -- under bright light.

"We used an escape motivation because if we had used food, the snakes could have detected it with their eomeronasal system [a type of chemical sensing perceived through the snake tongue]," Holtzman explains. "We designed the task to eliminate chemical cues and just test learning." The scientists then trained the snakes to learn and remember which hole led to shelter by guiding them to the hole with their hands. The results: the snakes learned fairly quickly how to escape.

"After four trials per day for four days, the snakes would go more directly to the right hole," Holtzman says. "On average, they take over 700 seconds to find the correct hole on the first day of training, and then go down to about 400 seconds by the fourth day of training. Some are actually very fast and find it in less than 30 seconds."

The researchers also found that it was harder to teach old snakes new tricks. The older snakes seemed to rely more heavily on visual cues, becoming. befuddled if the colored cards were tampered with. "Younger snakes were more variable in the cues they used, while old snakes were more restricted," Holtzman notes.

So does all this mean we could train a bunch of super snakes -- or teach snakes to become domesticated? "No," Holtzman says. "But this shows they're not just dumb animals wandering around aimlessly."

It also shows that snakes use similar brain mechanisms to learn as people. That's a conclusion that could have important implications, because snakes and other reptiles have an unrestricted ability to grow new brain cells throughout their lifetimes. Humans, meanwhile, can only produce limited numbers of new brain cells in the hippocampus, which controls memory and spatial perception.

"What regulates reptile brain growth?" Holtzman asks. "If we find out, it may help us produce brain growth in people with degenerative brain diseases like Alzheimer's or Parkinson's." Seems the "simple" snake has a lot to teach us, after all.