WYOMING – Imagine, you are walking with your dog. She’s out of your sight momentarily. Then you hear it. A strange hissing sound and your dog begins whining in a way you’ve never heard before—gasping for air. By the time you get there, and it was only seconds, she’s foaming at the mouth and convulsing. It’s over quickly. Within minutes. She lays still. Dead.
Two recent incidents highlight the increasing number of cases of pets and people injured or killed by cyanide bombs called M-44s. In most cases, the lethal devices are placed by a federal agency or private rancher to eradicate predators like coyotes and wolves. These devices have resulted in the death of three dogs in the past week—one in eastern Idaho, two near Casper, Wyo.—and have come under increased scrutiny by pet owners and advocacy groups.
Recent dog deaths

On Saturday, March 11, a Wyoming nurse named Amy was enjoying a family walk about 50 miles northwest of Casper. They had been to the particular spot many times before to antler hunt and let their dogs exercise. Amy’s companions that day included her husband, her 8-year old daughter, and their two Drahthaar dogs—Abby and Vita. Amy’s sister and brother-in-law also came along for the adventure and brought their two Weimaraners—Molly and Stella.
While returning back to their vehicle, Abby tripped an M-44. Amy’s husband quickly carried the dog to a nearby creek to wash off the cyanide, but it was too late. Molly was also covered in the deadly poison. The family gathered the remaining two dogs to keep them from getting near the device. Within minutes, both dogs were dead.

Days later, on March 16, the Idaho State Journal broke the story that a teenaged boy and his dog had stumbled upon a cyanide bomb on a hillside near their home on West Buckskin Road in Pocatello, Idaho. Canyon Mansfield, 14, was knocked down by the blast and covered in cyanide. His dog, a 3-year-old lab named Casey, was dead within minutes. Mansfield was treated at Portneuf Medical Center and released.
Public outcry
Wyoming Untrapped and Predator Defense are two organizations calling for a ban on M-44s, saying the devices kill indiscriminately and are often poorly marked if marked at all. The M-44 in Wyoming was believed to be placed by a county-hired trapper. The Idaho bomb was planted by an obscure federal department described by one US Congressman as “secretive,” “unaccountable,” and a “rogue agency.”
Peter DeFazio, D-Oregon, has repeatedly called for a congressional investigation of Wildlife Services. The agency is nested under the U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS). Its main job is to kill wild animals that threaten livestock—especially predators like coyotes, wolves, and cougars.
“I’ve served on the Homeland Security Committee, and Wildlife Services is more difficult to get information from than our intelligence agencies,” DeFazio told Harper’s reporter Christopher Ketcham last year.
Wildlife Services’ arsenal incudes M-44s—spring-loaded metal cylinders that are baited with scent and fire sodium cyanide powder into the mouth of whatever tugs on them. They’ve been used across the West to protect livestock for seven decades.
According to its annual Program Data Report, WS killed at least 3.2 million wild animals in 2015 alone (including 69,905 coyotes, 384 gray wolves, 284 cougars, 480 black bears, 731 bobcats, 1,511 gray foxes, 1,534 red foxes, 20,334 black-tailed prairie dogs, and 21,557 beavers). The tally also included 17 domestic dogs. Agency records show that more than 3,400 animals have been mistakenly killed by M-44s since 2006.
Agency defends killing methods
WS has defended the use of M-44s, stating, “M-44s, unlike leg-hold traps, kill rapidly. Unconsciousness, followed by death, is very quick, normally within one to five minutes after the device is triggered. Animals killed by sodium cyanide appear to show no overt signs of distress or pain.”
WS issued the following statement last Friday after the killing of the Idaho dog: “APHIS’ Wildlife Services confirms the unintentional lethal take of a dog in Idaho. As a program made up of individual employees many of whom are pet owners, Wildlife Services understands the close bonds between people and their pets and sincerely regrets such losses. Wildlife Services has removed M-44s in that immediate area. Wildlife Services is completing a thorough review of the circumstances of this incident, and will work to review our operating procedures to determine whether improvements can be made to reduce the likelihood of similar occurrences happening in the future.
“The unintentional lethal take of a dog is a rare occurrence. Wildlife Services policies and procedures are designed to minimize unintentional take or capture of domestic pets. It posts signs and issues other warnings to alert pet owners when wildlife traps or other devices are being used in an area for wildlife damage management. This is the first unintentional take with an M-44 device in Idaho since 2014.”










