Cool critters: Harmless snake that slithers in darkness has a trick up its tail

The northern desert night snake may look deadly, but rest assured, it is just pretending. Aptly named for how they emerge from crevasses and beneath rocks at night to hunt for food, these reptiles not only resemble rattlesnakes, they also mimic them.

Scientifically known as Hypsiglena chlorophaea deserticola (yes, it’s a mouthful), the 18- to 26-inch-long night snake is found in parts of the western United States, including Eastern Washington. They are most concentrated in the Columbia Basin, according to the Washington Department of Fish and Wildlife night snake webpage.

Most active from April to October, night snakes eat lizards and their eggs, frogs, toads, salamanders and small mice, WDFW district wildlife biologist Scott Fitkin said. They subdue their prey with a mild venom that “poses absolutely no threat to humans,” he said.

Still, being that many people are fearful of snakes, venom is not a word to use lightly. So keep in mind that most, but not all, rear-fanged snakes produce just enough toxins in their venom to subdue small prey such as frogs and lizards, according to a 2016 paper published in the journal Integrative and Comparative Biology. And wouldn’t you know, one of those nontoxic-to-humans reptiles is the night snake, researchers concluded.

“Night snakes are harmless and timid,” Fitkin said.

But they don’t always look that way.

Here’s why: The northern desert night snake is brown, beige or pale gray, with dark blotches on its upperside. It also has a triangular-shaped head. When threatened, it flattens that triangular head, coils its body, raises its tail tip and shakes it.

Sounds familiar, doesn’t it?

“People often confuse them with juvenile western rattlesnakes, but in terms of appearance, a big difference is the fact that night snakes don’t have rattles on their tails,” Fitkin said. “They create an illusion of being dangerous to protect themselves from predators.”

Night snakes display smooth scales, unlike the ridged scales of rattlesnakes. They also have smaller blotches than rattlers. And you know those two trademark fangs that descend from the upper front of a rattlesnake’s jaw? You won’t see them there on a night snake.

That’s because it’s a rear-fanged snake, Fitkin said.

“Unlike the rattlesnake’s front fangs that inject venom into prey, the night snake chews its venom into the prey,” he said.

Of the 15 snake species native to Washington state, the western rattlesnake is the only one that’s venomous to humans, Fitkin said. But remember, even if you hear its alarming rattle during a hike, “it’s a message of warning, not aggression,” he said.

In other words, back off is what the rattler is saying – the same message the night snake sends as it shakes the tip of its silent tail.

The gopher snake is another harmless species that shakes its rattle-less tail when threatened. Like the northern desert night snake, the gopher snake resides in semiarid and rocky canyon regions of Eastern Washington. Where the night snake has vertical pupils, is slender and roughly 2 feet long, the gopher snake has round pupils and a thick body that can reach a length of 6 feet.

Although night snakes, gopher snakes and rattlesnakes lack the charisma of koala bears and dolphins, try not to panic if you encounter one.

After all, vibrating the tail-end is a warning from the rattler and a ruse from the other two. And perhaps they are more afraid of you than you are of them.