Which animals scavenge human remains in Alberta? This study used dead pigs to find out

People who search for human remains in Alberta say a new study identifying predominant scavengers in the region will help them conduct their searches more efficiently.

In August 2021 and August 2022, researchers placed pig carcasses at four locations — one near Edmonton, another near Calgary and two in more rural areas.

The 200-pound pigs acted as analogs for human remains so researchers put dresses, shorts and shirts on them.

"It probably looks ludicrous, but we are trying our best to recreate a human environment and if we think about somebody who's gone missing whilst they're hiking or camping, this is what they're potentially going to be wearing," said Shari Forbes, a forensic scientist at the University of Windsor who led the research.

Forbes's team monitored the remains with trail cameras and once scavenging was complete, searched the areas to recover what they could.

They published some of their findings recently in the Journal of Forensic Sciences, a peer-reviewed publication of the American Academy of Forensic Sciences.

Which scavengers showed up?

Coyotes and magpies were the predominant scavengers in three of the four locations. 

Only the rural location in southern Alberta saw black and grizzly bears more often. 

Foxes, skunks, fishers and, at one of the Edmonton sites, a turkey vulture, also scavenged remains, but some creatures passed by without displaying any interest in the carcasses.

The Alberta research, which was supported by federal funding agencies, was based on a previous study Forbes conducted in Ontario with the Ontario Provincial Police.

Forbes found the time it took for remains to decompose and be dispersed was longer in Alberta than in Ontario.

She said her next publication will focus on dispersal distances and the percentage of remains that were recovered.

How can this help police?

Police and civilian search groups are interested in learning more about scavengers in their areas because that could help them better search for human remains.

Forbes said coyotes, particularly those in Edmonton, often feed in groups. And they try to move remains into safe areas.

Police teams, who worked with Forbes to select the experiment locations and search for remains, have found the results informative.

"If we're in an area where we have, likely, coyote scavenging… our search areas need to be significantly larger than we probably would have expected in the past," said Sgt. Ian Vernon with the Calgary Police Service canine unit.

Edmonton police also participated in the research but declined an interview request.

Vernon said calls for the police to find human remains have been increasing and the more police know about the areas they are searching, the more likely they will be to find evidence.

"It really helps us get a better picture of how to get a complete search," he said.

Local search and rescue groups are also interested in the study's findings.

Michelle Limoges, a founding member of the Search and Rescue Dog Association of Alberta, said her volunteer organization gets called out to searches in the Edmonton area about once a month.

She said the study confirms her theories about what coyotes and magpies were up to.

"I was on a search years ago and the skull of this individual was found 1.3 kilometres away from where the person passed away," she said. 

Limoges said she is looking forward to learning more about how the remains were dispersed — information Forbes said will be published in a forthcoming paper.