Wildlife biologists utilize distinct clues when identifying predator killsWritten by Saige Albert
Bears, wolves, mountain lions and coyotes can all be problematic predators in the sheep industry.
“Our four large carnivore species consistently leave different bite-mark patterns,” says Mike Boyce, Wyoming Game and Fish Department (WGFD) large carnivore biologist. “Each large carnivore species utilizes different techniques for killing their prey.”
Assessing predator kills
In identifying predator kills, Boyce comments that it is important to ensure that biologists are contacted as soon as possible to ensure that kills can be identified.
“It is key to try to preserve the evidence at kill sites,” Boyce says. “A lot of times, we may have dogs, horses or other livestock tracking through the sites. We need to be called right away so we can get in and do our work before evidence is lost to the natural elements.”
He further adds that it is necessary to have at least an intact hide or skull to determine cause of death in livestock.
“It is difficult to verify kills if all we have to work with is a pile of old bones,” he says. “Having a fresh kill to work with makes it easier for us to determine cause of death.”
When called onto a scene, Boyce says that he begins by assessing the site of the deceased livestock animal. For example, tracks and other clues may indicate what killed the animal.
Then, the biologist skins the animal to assess damage under the hide.
“A lot of times there isn’t much visible external damage,” he explains. “When we have the hide pulled back, we have a better image of what might indicate death.”
In addition to deceased animals, Boyce comments that “walking wounded” animals are common.
“We look at a lot of walking wounded animals, mostly cattle,” he adds.
Starting with bears, Boyce notes that both grizzly and black bears employ similar killing techniques.
“We often see canine tooth punctures and associated damage, most often on the mid-dorsal line along the back,” he explains. “We also often see damage to the head and snout.”
The bites result in significant damage and hemorrhaging under the surface of the skin.
Another common injury with bear kills is bite wounds on the withers or head, which is something that is almost always present in bear kills.
“After bears make a kill, they often cache their prey,” Boyce continues. “We see this with both bears and mountain lions. They conceal the carcass from other scavenging species.”
Wolves are another predator that impact livestock herds.
“We certainly look at a lot of wolf damage,” Boyce says. “With wolf predation, we see damage to the hind quarters, armpit area, throat, head and neck. It is also typical to see damage to the hamstrings.”
The damage from a wolf kill is more significant than from coyotes.
“Wolves have more biting force and cause a lot more hemorrhaging than coyotes,” he says.
Wolf kills also often have tooth channels present.
“We see tooth channels more in cattle than in sheep,” he adds. “When wolves make kills, they take multiple bites and cause significant damage.”
Another predator, the mountain lion, is both powerful and efficient.
“Mountain lions kill their pray by grasping with forepaws, and they usually take one targeted bite to the head and neck region,” Boyce says. “Occasionally they will bite the throat.”
Large diameter canine punctures are seen in the hide of animals killed by mountain lions.
In addition, lions usually select for lambs and calves over mature animals, as the young livestock are easier to secure and kill.
“With mountain lions and wolves, we sometimes see surplus killing where multiple animals are killed in one event.” he adds. “Lion kills are usually associated with some sort of cover, whether that is rim-rock, timber or vegetation. When they make a kill, they will usually move it to the closest cover.”
Lions also exhibit caching behavior.
Finally, coyotes can be a problem for livestock producers and sheep producers in particular.
“The Wyoming Game and Fish Department doesn’t manage coyotes,” Boyce comments. “Local predator management boards and USDA are tasked with working on coyote damage situations.”
However, it is useful for producers to be able to identify coyote kills.
“We see similar types of inflicted damage with coyote and wolf kills,” he notes. “The damage is usually smaller and more subtle with coyotes than with wolves as the canine teeth are smaller and coyotes have less biting force then wolves. We typically see damage at the point of the jaw, along the flanks and at the hind quarters.”
The size of the puncture marks and bite mark patterns can rules out other large carnivores species when determining cause of death.
After verifying the source of a livestock kill, Boyce notes that several actions can be taken.
“If the damage becomes chronic, we will attempt to capture the offending animals,” Boyce explains.
Bears can be captured in culvert or box traps or using cable snares, depending on the situation.
“We capture lions involved in conflicts using box traps,” he says. “We can also put snares to capture lions, or we use hounds.”
WGFD does not employ a “strike policy” for predators that are depredating livestock.
“We work with the U.S. Fish and Wildlife Service when federally protected species like grizzly bears and wolves are involved in livestock damage,” he says. “Bears that are captured and relocated are tagged, and grizzly bears are released with radio collars so that they can be tracked.”
In addition, WGFD has a compensation program for verified predator kills, excluding coyotes.
“In an open range setting, we pay three-to-one for bear and lion kills and seven-to-one for wolf kills,” Boyce comments. “We use a multiplier to account for missing animals.”
Boyce presented at the 2015 West Central States Wool Growers Convention, held at the beginning of November 2015.