State veterinarian Walt Cook assists a striken elk back to health at the State Veterinary Laboratory, March 6, 2004, in Laramie, Wyo. Experts report at least 289 elk have fallen ill and died in south-central Wyoming over the past month. The animals slump to the ground eventually succumbing to thirst, scavengers or, mercifully, the guns of Wyoming Game and Fish Department employees. An intensive effort has yet to yield an answer to the dieoff, which experts say is unheard of in any scientific literatureworldwide. (AP Photo/Wyoming Game and Fish Department)
By MEAD GRUVER, Associated Press Writer
LARAMIE, Wyo. - As the Wyoming countryside begins to thaw, biologists and game wardens are canvassing the rugged terrain to solve an alarming mystery: Why have hundreds of elk slumped to the ground and died in less than two months?
Despite intensive research, the wildlife deaths have stymied state officials, who have investigated a host of theories ranging from deliberate poisoning to exposure to heavy metals.
"The only time we've ever seen any deaths like this before have been winter-related deaths — severe winters, starvation-type things — which is not the case," state veterinarian Walt Cook said.
At least 289 elk have been affected in south-central Wyoming since early February. The sick animals usually slump to the ground and cannot get up. Many eventually die of thirst. Some have also been euthanized by employees of the state Game and Fish Department.
Cook's specialty is investigating mysterious animal deaths. He first looks for the telltale brain perforations of chronic wasting disease, the deer-and-elk version of mad cow disease.
But chronic wasting disease was quickly ruled out after the first sick elk turned up Feb. 6. Also crossed off the list have been most viruses and bacteria, as well as malnutrition, exposure to heavy metals such as arsenic, and the possibility of poisoning from a leaky gas well or pipeline.
Officials have discounted any foul play because deliberate poisoning of so many wild animals would be virtually impossible.
"We've basically ruled out all those common things, and so now we're just looking at what are all the uncommon things," Cook said.
Officials are also checking whether the elk may have become so frightened they ran themselves to exhaustion; been bitten by ticks, which carry a mild toxin in their saliva; or consumed monensin, a feed additive for cattle that is poisonous to many animals including elk.
For a time, researchers used a helicopter to find as many afflicted elk as possible, but at $900 an hour the flights were becoming expensive.
Lately they have focused on lab work, which begins with driving into the rough country near the Continental Divide and traipsing through melting snow and mud to snip plant specimens and scoop up elk droppings.
At the lab's warehouse-sized autopsy room, some elk have been dissected for analysis by pathologists and toxicologists. Tissue samples were sent away for more detailed tests.
Another idea has been trying to keep four sick elk alive by rehydrating them and providing nourishment. But after a week, one died, two worsened and had to be euthanized, and the fourth did not improve. That ruled out vitamin or mineral deficiency.
The failures have been frustrating to employees.
"As you can imagine, it was a pretty heavy emotional toll on them because they were shooting most of these elk to put them down," Cook said. "And they were continually asking us, do we absolutely have to do this? Is there any other option?"
Valerius Geist, an elk expert in British Columbia, said he has never heard of such a die off in his 48 years of research in the field.
With so many possibilities ruled out, about the only one left is that the elk ate a toxic plant.
Any toxin in the air or water would likely affect a variety of animals, including antelope and deer. And if that happened, elk are the toughest and would probably be the last to fall, not the first.
Elk also dine from a different menu than other vegetarians of the backcountry. Antelope and deer might not be eating toxic plants.
"The thing that really makes this unusual is we have about 50 elk that are about 10 miles north of this herd ... and they're fine," said Greg Hiatt, a state wildlife biologist.
Scientists speculate that a plant species the elk were used to eating may have become poisonous. Geist said plants can become more toxic the more they are grazed. "That's how they protect themselves," he said.
Another possibility is that the elk arrived in Wyoming from elsewhere, perhaps as far away as Colorado, and ate a toxic plant without knowing any better.
Lab tests should shed light on those theories. When the results are complete, Cook wants to gather possible poisonous plants and feed them to healthy elk to see if they develop similar symptoms.
"If they do, then we'll have the answer. If they don't, it's one more thing to cross off the list and move on," he said.
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On the Net:
Wyoming Game and Fish: http://gf.state.wy.us/