Elk carcasses on refuge assessed for cause of deathApr 5, 2017 The Associated Press
JACKSON (AP) -- Weeks or even months after the death of the rotting calf elk he was about to peel off the pasture, Wyoming biologist Tim Pratt knew the animal was in rough shape before its life slipped away.
The strike of a hammer on the calf's exposed femur revealed marrow with no resemblance to the pasty, whitish substance that domestic dogs are so fond of tonguing out of animal bones. Instead, the marrow the National Elk Refuge biological technician assessed looked like red jelly.
"Red-brown gelatinous is the worst criteria," Pratt said on a recent Thursday during an annual round of collecting elk carcasses. "That means it was on its last leg of energy, and it had been sick for a long time."
The young elk's hooves were of normal shape and size, indicating that bacterial hoof rot was not the agent of death. Putrid meat from the carcass was about 50 percent scavenged, but Pratt saw little indication that the animal's life was taken by a predator. Its jaw was smashed and partially missing, having been bitten off or run over by one of the feed tractors that distribute alfalfa pellets to thousands of members of the Jackson Elk Herd each winter.
Before Pratt winched the calf into a trailer to haul it away, he explained that part of the reason carcasses aren't left afield to break down is to limit the spread of disease. Getting the pelts off the grass so they don't inhibit the growth of forage is another consideration.
This year -- coming out of a severe early winter at all elevations -- about 2 percent of the elk herd overall and 10 percent of the calf population succumbed to disease, predators, injury or the elements. A handful of pronghorn and a lone emaciated cow bison didn't survive.
Since Pratt was hired full time, mortality rates have jumped. Between 6 and 10 percent of calves are now discovered dead annually, whereas the rate used to be nearer to 3 or 5 percent. The reason likely isn't that more elk are dying but, rather, that there's an employee devoted to the task of documenting their deaths.
Bodies discovered on slopes and in wetland areas are left to biodegrade. But on flat, dry ground Pratt is the man who is usually hauling them off to a carcass dump on the west side of Miller Butte.
Really, the reason that we're removing the carcasses is because of the equipment," Pratt said. "The Challenger feed vehicle, each track on those runs about $10,000.
"You hit a rib cage or a spinal column, and it can puncture it," he said.
Former refuge biologist Bruce Smith developed the protocol for recording and removing carcasses on the refuge in the early 1980s. One goal is to document all of the carcasses, which, combined with precise censuses each winter, allows refuge managers to come up with mortality rates.
TThe third and fourth elk Pratt picked up Thursday morning were animals he had previously documented as dead and inspected but, earlier in winter, were frozen to the ground and couldn't be carried off. Months later they were sufficiently thawed -- and rank.
On the drive back to the Elk Refuge shop Pratt spotted a trophy bull he'll likely be visiting soon. Visibly gaunt, the animal was bedded by a horse pasture and had scarcely moved since he last saw him -- a sign the end was near.
"He's not going to be around more than a couple days," Pratt said.
Information from: Jackson Hole (Wyo.) News And Guide, http://www.jhnewsandguide.com