By Susan and Biff Andrews

“A narrow fellow in the grass….”

On a recent walk at Lone Star Lakes Park, we encountered two black snakes.

Same species, right? Not so. One was lighter on the stomach and looked scaly, as well as being chunkier.

In our area we have both black rat snakes and Northern black racers, so which was which? I’ve never been able to tell the difference, so I set out to do some investigation.

The Northern black racer — ”coluber constrictor” — is a common shiny black snake found all through Virginia. There’s a little white on the chin and throat, but basically they’re shiny black all over. They grow to a length of 60 inches and are usually slender and very fast. The cross-section of a black racer is almost totally round.

Quick to flee, these snakes fight fiercely when cornered and will climb a bush or small tree to escape. While the Latin name leads one to believe they squeeze their prey to death, in fact they basically hold and smother them.

The black rat snake — “elaphe obsoleta” — is also found throughout the state. It is a much stouter specimen. While the chin is white, the belly is usually cream-colored.

This snake is heavy-bodied and longer — up to 72 inches — and its cross-section looks like a loaf of bread, flat on the bottom, rounded on top. It is a true constrictor, squeezing its prey to death.

Both species prey primarily on rodents, but will also eat birds, frogs and lizards. Both species are found in grasslands and woodlands, especially around barns or woodpiles. Both species are checkered or variegated when young, then become more uniformly black when half-grown.

About 10 years ago I watched a black snake climb a medium pine tree, slither out on a limb, and dine on a family of doves in a nest. Black rat or racer? (Answer: Black rat — they have rougher scales and are far better climbers.)

About 20 years ago, my son and I encountered a lengthy specimen simply hanging from a small tree, about five feet off the ground. Black rat or racer? (Answer: Black rat. Racers can climb like that, but usually do so only when threatened.)

Last week, when we encountered the two snakes, the first one, about 4 feet long, reversed direction and quickly disappeared into the woods along the road in one swift movement. The second snake froze as we approached, its 5-foot body a series of tight s-curves. After a while, it leisurely turned away and slowly entered the brush. Which was the racer?

(Answer: The first one, whose speed and slender double s-curve differentiated it from its chunkier counterpart.)

It’s elementary, my dear Watson.

Susan and Bradford “Biff” Andrews are retired teachers and master naturalists who have been outdoor people all their lives, exploring and enjoying the woods, swamps, rivers and beaches throughout the region for many years. Email them at b.andrews22@live.com.