Northern California Mountain Lion M166: The Horse Predator
October 29, 2018
In Northern California, a mountain lion known as M166 has gained notoriety for preying on wild horses. This unusual behavior has sparked discussions about wild horse management in Modoc County, where the local ecology is strained by the large populations of both horses and mountain lions. The story of M166 highlights the complex relationship between wildlife and human intervention.
The Predator: M166
It has been 10 days since M166 last killed here, but the smell of death still lingers. Pieces of a wild horse are scattered among the dirt and grass. A red rib, not yet sun-bleached, lies in the dirt. A vertebra of spine rests by a sage bush. Tufts of the horse’s dark mane sit among the black and brown lava rocks. Coyotes, vultures, and bobcats have already scavenged the remains.
Less than 300 feet away, a herd of wild horses graze, unfazed by their proximity to the dismembered 10-month-old foal. Prowling a home range of about 386 square miles, M166 has developed a reputation as a horse killer par excellence.
Local Reactions
Local ranchers, who believe this part of rural Modoc County has too many wild horses, grudgingly respect the mountain lion's actions. They wish more cougars had a knack for reducing the horse population, which might alleviate the issues that arise when humans intervene.
“It’s kind of a split decision around here,” said Teri Brown, owner of Modoc Farm Supply. “A lot of people who have lived here their entire lives have never seen populations like this — both of horses and mountain lions — and both make them uncomfortable.”
Wild Horse Management
For weeks, a helicopter has been gathering 1,000 of the estimated 4,000 wild horses in the Devil’s Garden. Experts say the 258,000 acres can sustain no more than 402 horses without significant ecological damage. This effort has led to complaints and lawsuits.
Even in an area with a dense cougar population, M166 can only do so much. He has killed more than 30 horses since June 2017. At one scene, he also killed a beaver and a dove.
“This lion, he is just wired for horse,” said David Garcelon, president of the Institute for Wildlife Studies. “It was one of those things where you go in the first time, and it’s ‘Oh my gosh, he’s taken a horse,’ and pretty soon, you’re like ‘Everything he takes is a horse.’”
Controversy and Conservation
The plan to reduce the horse population has been controversial, leading to lawsuits by wild horse advocates. They argue that the U.S. Forest Service is ignoring science in favor of cattle ranchers and suggest using fertility control on mares instead of helicopter roundups.
“In the big picture, the Forest Service got here from a basic failure to manage the horses for years,” said Suzanne Roy, director of the American Wild Horse Conservation (formerly American Wild Horse Campaign). “These mass roundups are not only cruel — they also don’t work.”
Horse advocates argue that blaming wild horses for ecological damage ignores the thousands of cattle and sheep grazing on Modoc’s public lands.
As of Friday, 628 wild horses had been removed from the Devil’s Garden Plateau Wild Horse Territory. A mare with a chronic condition was euthanized, and a foal died in holding.
The most controversial aspect is the decision to sell horses 10 and older without limitations if not adopted by January. Although California law prohibits selling horses for slaughter, advocates fear older horses could be taken elsewhere and killed.
Amanda McAdams, Modoc National Forest supervisor, said they aim to get horses adopted to avoid this option. “We love these horses,” McAdams said. “I feel like we’re doing the right thing, and the right thing is really controversial.”
M166's Impact
M166 is doing his best to kill horses — about one per week. A husky cat, M166 has a strong jaw and thick neckline. When captured and collared, he weighed 138 pounds, similar to an adult male St. Bernard.
He measured 7.25 feet from nose to tail, typical for a male mountain lion. His horse-killing canine teeth were a little longer than an inch. At capture, he had a chip out of his upper right canine, a tear in his right ear, and scars on his neck and left side.
No one knows where M166 was born or how he learned to kill horses, but biologists note that after a big cat dines on equine, they’re less enthusiastic about cervine.
“Once they get a young horse, I think they realize, ‘Oh my gosh, this is way easier than a deer,’” said Meeghan Gray, a biology professor at Truckee Meadows Community College.
All the horses M166 killed were younger than 14 months. The largest was about 350 pounds. Mustangs generally weigh between 700 and 900 pounds, with foals much smaller.
M166 spends at least three days at a kill site, eating a small part before moving on, creating a food chain for coyotes, bobcats, and vultures.
Beyond horses, his options include deer and pronghorn antelope, which are fast and difficult to catch.
By comparison, mountain lions in Southern California kill mostly deer, eating the carcass for three to five days.
“Whenever they make a kill, they’ll go in right in the abdominal cavity,” said Jeff Sikich, a biologist with the National Park Service. “They’ll eat the heart, the liver, all of that first.”
It’s unknown whether removing 1,000 horses will alter M166’s appetite. Many in Modoc hope he doesn’t change.
“It’s just one mountain lion that we know of, and they say it is eating about one horse a week,” said Laura Snell, Modoc County director at UC Cooperative Extension. “But even at those numbers, we’re not even making a dent in the population.”
A mountain lion is an apex predator, and its greatest threat is humans. In Modoc, a cattle drive might cause a brief traffic jam, as ranchers move cows.
When a mountain lion kills livestock, it can be hunted if the California Department of Fish and Wildlife issues a depredation permit. In 2017, three mountain lions were killed in Modoc County under these permits.
Fortunately for M166, cattle does not seem to be on the menu.
Originally posted by LA Times