Red Rim Elk Mystery Solved

Send by email Printer-friendly version Share this

A little plant that is part fungus and part alga is responsible for the deaths of nearly 300 elk near here. The plant is a lichen known as Parmelia that is abundant in desert soils around the state.

“We had lichen on the list of toxic plants that our veterinarians were investigating,” said Tom Reed, spokesperson for the Wyoming Game and Fish Department. “We were faintly optimistic that this may have been the cause, but didn’t want to get our hopes up.”

This past weekend, tests revealed that the lichen was indeed the cause of the strange affliction that had taken down 295 elk in a month’s time. On Feb. 8, two cow elk were discovered in the desert about 15 miles southwest of Rawlins that could not rise and run when approached by agency personnel. As field crews searched the area in subsequent days, the number of elk afflicted slowly increased to nearly 300, scattered over a 50 square mile area of high desert in and around the department’s Daley Ranch wildlife habitat area. All exhibited the same symptoms: inability to rise from the ground, while remaining alert and vocal. Elk that were not found and euthanized by agency personnel died a slow, stressful death from starvation or dehydration.

Scientists found parmelia in the stomachs of afflicted elk, starting an exhaustive chain of investigation. That effort was borne out this weekend, when captive elk that had been on a diet of parmelia went down with the same symptoms, said Dr. Terry Kreeger, a veterinarian with the department.

Parmelia produces an acid that may break down muscle tissue, causing the elk to lose strength, said Dr. Walt Cook, who has been working on this incident non-stop since it was discovered more than a month ago. Cook and colleagues at the Wyoming State Veterinary Laboratory were instrumental in narrowing down the laundry list of possible causes, but more work will need to be done in coming weeks.

“We are going to need to do further necropsy work to explore the exact physiology behind this,” said Cook.

Additionally, officials are going to try to learn more about the lichen itself and why, or if, it accumulated inordinately high amounts of acid this year.

“There are a lot of factors we’ll need to look at,” said Reed. “Do elk eat this lichen in normal years? If so, why hasn’t this happened before? Does a long history of drought weigh in somehow? If so, what are our management options in the future? These are all questions we are going to try to answer in the coming months.

“But we’ve answered the biggest and most important question: What the heck is killing these elk?” said Reed. “It’s a huge relief for everyone involved. A lot of people worked their tails off on this mystery. But we have some of the best minds in wildlife science right here in Wyoming and they came up with results.”

Healthy elk that were wintering on the Daley Ranch southwest of here are now following the receding snowline back toward the Sierra Madre mountains, and three cows in that herd are wearing radio collars so biologists can learn a little more about this elk population.

“Elk don’t normally winter down on the Daley unit where they ate the lichen,” said Reed. “But for whatever reason, this year they moved in there. Elk are incredibly adaptable, tough animals. They’ll get by on thin rations and they’ll make do somehow. But this year, nearly three hundred of them paid the price for that adaptability.”

No other animals including horses, cattle, antelope, deer or scavengers in the area were afflicted.