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Science

Researching red-bellied snakes of the Black Hills

The prairie rattlesnake is like the Black Hills' reptilian Potato Creek Johnny. Rattlers in general, and Tater in particular, star in many a good yarn.

Red-bellied snakes, on the other hand, are rather low profile little slitherers. You could almost say they live under a rock, which in fact is what they do -- severally, not the same rock.

Due to their diminutive size and their rather small range they are not very well known. South Dakota's Department of Game, Fish and Parks (GFP) tracks them on a list of rare animal species.

"This is an isolated population compared to the rest of their distribution," explains Dr. Brian Smith, Professor of Biology at Black Hills State University. "They get as close as the border of Eastern South Dakota, then you don't find any of them till you get all the way out here in the Black Hills."

Even in the Hills, red-bellies seem to cluster in small groups.

"We're a little worried about these snakes because they're small populations, they're probably a little bit inbred, and you go very far and you just don't find a population until you get (we don't know how) far away, but sometimes miles and miles away. And these small populations that are found across two hundred, three hundred feet of habitat can be easily wiped out with very small development projects and minor habitat changes."

The more scientists learn about their habitat and needs, the better they'll understand how they might be protected.

"We've got one population that seems to have largely disappeared because the active season habitat and the den sites they're using are right on the other side of the road. Road traffic is a huge source of mortality for most wildlife and particularly for snakes because they don't move very fast. These guys, particularly don't move very fast because they're so small. We think they only move about one hundred feet or so in their lifetime."

To find red-bellied snakes, Dr. Smith and graduate student Kailey Devries look for them by turning over rocks in known habitat. The rocks don't have to be big. Red-bellies only grow a maximum of 10-12 inches long.

Devries is learning more about red-bellied snake habitat by researching what they eat. "We collect fecal samples in the field, which then go into the lab, go through a DNA extraction process. From there, we amplify that DNA, it goes through analysis, and what we get is information [about] species the red-bellies could be eating."

That information could be key to conserving the species. "You kind of focus on making sure that you have those prey items available, so that you're not wiping out an entire species of beetle or something from the Hills, because the snake relies on that to survive."

"In the past without the DNA techniques that we have now, you just couldn't do this," says Smith. Trying to extract food matter from such tiny snakes would endanger the snakes. "A big worry would be killing them," says Smith.

The work Dr. Smith and graduate students at BHSU have been doing on red-bellies and other small snakes -- with funding from GFP and the United States Forest Service -- is contributing to the accumulation of scientific knowledge about small snake ecology.

"I've had quite a few students work with this snake now and we're getting some really unique data that just has never been published before," says Smith.

"My graduate students have worked on things like conservation genetics to see how much inbreeding there might be, how big the populations are, how widespread they are, and we're currently working on food habits. A lot of these small snakes like red-bellied snakes, people just don't do much ecology work on them because they're so small and so hard to work on. We have more research on red-bellies than anybody has anywhere. So most of what we're finding here is unique to science."