WILDLIFE — River rafters, hikers and hunters are keenly aware that rattlesnakes are common on portions of the Selway River.
But why are there virtually now rattlesnakes on the Lochsa River, which joins the Lochsa near Lowell, Idaho, to form the Middle Fork Clearwater River?
Eric Barker, outdoor writer for the Lewiston Tribune made a strike at answering that question in a recent story that pegged on the scene in a Norman Maclean story noting a rattle snake between Grave Peak and Elk Summit.
The Selway is lousy with rattlers and the snakes can be found at some unexpected places, said retired outfitter and packer Jim Renshaw of Kooskia, noting that he killed a rattlesnake on top of Fog Mountain at an elevation of 5,000-6,000 feet.
Chuck Peterson, a herpetologist at Idaho State University, told Barker that rattlers can be found at elevations that would surprise many people. He said it is possible they can survive at Elk Summit, which sits above 6,000 feet.
“Every now and then you get some snakes in some elevations you wouldn’t expect them,” he said. “I don’t know about up there but further south, I think the highest elevations (where rattlers have been found) are near 7,000 feet around Challis.”
Some rattlesnakes will climb a few thousand feet to hunt in the warm summer months, he said. But they generally can’t survive long term at such heights. The seasons there are too short for the females to build up enough energy reserves to reproduce.
“We found out in areas that have less than 58 frost-free days, that seems to be the cut off point.”
But aspect and exposure are important to consider. He said snakes can survive at higher elevations if they are on sun-rich southern exposures.
Sometimes it’s difficult to know why rattlers are in one spot and not another. The Lochsa and Selway rivers are a prime example. The Selway is known for its abundant rattlesnake population and the Lochsa is all but free of them.
Marty Smith of Three Rivers Rafting at Lowell has often wondered why. He has spent much of his life at Lowell where the two rivers join to form the Middle Fork of the Clearwater. He’s never seen one on the Lochsa and has rarely seen them less than 10 miles from the mouth of the Selway.
But starting at the falls and proceeding up stream they are common in some. When Smith is on the river he thinks carefully about where he places his hands and feet. On the Lochsa, he is much more relaxed.
“I’m always surprised I have never ran across any on the Lochsa and on the Selway of course I have seen hundreds of them, if not thousands,” he said. “It’s the same terrain. You walk around on the (Lochsa’s) river bank on a pile of driftwood or bark and I always say, ‘I’m glad I’m not on the Selway right now or I’d be more on my toes, I would probably walk around that.’ ”
In other words, nobody Barker contacted has yet figure out why rattlers draw the line at the Lochsa.