How researchers are working to preserve caribou collective memory and migratory routes

No animal roams quite like the barren-ground caribou. The ungulate – hoofed mammal – has the longest seasonal migration of any land animal, spanning around 1,300 kilometres between forested areas in the winter and the Arctic tundra in the summer. These specific migration routes can vary greatly, depending on the weather conditions – an adaptability that researchers suspect may stem from a survival tool: collective memory.  

There’s no tangible evidence that caribou have memory the way humans have memory, but researchers, such as biologist Anne Gunn, have observed tundra caribou change migration routes based on past experiences. If a route is too icy and foraging is difficult, for instance, older female caribou – who lead the herd – may remember a different, less icy path they used a previous year.  

“The average cow lives, say, 15 years, and she will have learned [routes] from her mother, because when she was a yearling, she will have followed her mother, who would have followed her mother,” Gunn says. “So there’s collective memory. They learn from each other.” 

As the barren-ground caribou population declines – with the Bathurst herd in particular thinning out by 98% – the risk of caribou losing their collective memory increases. The key to retaining that memory, beyond ensuring the population doesn’t go extinct, is making sure those migration routes stay accessible to caribou, Gunn says. But infrastructure initiatives in the Canadian Arctic, such as the proposed 400-kilometre all-season road from the Northwest Territories to Nunavut, are poised to cut through a significant portion of caribou migration range, blocking the routes these animals have crossed for millennia. 

“We know that caribou, especially barren-ground migratory caribou, really do not like crossing roads,” says Elie Gurarie, professor of wildlife ecology at the College of Environmental Science and Forestry at the State University of New York.  

Researchers have a good sense of how caribou might react to the all-season road based on their behaviour on smaller roads linking the Diavik and Ekati diamond mines in the Northwest Territories to Yellowknife. These mining roads are not open to the public, with traffic increasing seasonally along with mining activity. 

Data from GPS-collared caribou – collected by the Northwest Territories’ Department of Environment and Climate Change – have recorded caribou crowding along the sides of these roads when traffic is active, unable to cross and roam their natural range. “Caribou are just remarkably successful in the Arctic,” Gurarie says. “The environment is really harsh and not very protected. I think the key to that success is that collective memory, their sociality and their freedom to move.”  

Barren-ground caribou have extremely variable migratory routes, so it’s not as simple as making sure one path is free for them to use. They need a lot of space to roam. When it came to the diamond mine roads, one solution, Gunn says, was to close these roads for a few hours each day during the high migratory season.  

The proposed all-season road, however, is much bigger than the mining roads. It’s part of the $40-billion Arctic Economic and Security Corridor linking mines, military operations and communities under Prime Minister Mark Carney’s nation-building projects list, which allows it to be fast-tracked through the approval process. A portion of the road, called the Grays Bay Road and Port project, cuts right through the dwindling Bathurst herd’s migratory range.   

If we don’t look after the herd well enough when they’re declining, and we lose most or all of a herd, all that collective memory of the landscape is lost.

— Anne Gunn, biologist

But there are three ways the impact of the road on caribou can be mitigated, Gurarie says. The government could collaborate with researchers and local Indigenous wildlife monitoring groups – including the North Slave Métis Alliance, Tlicho Ekwǫ̀ Nàxoèhdee K’è and Yellowknives Dene First Nation – to map a route least intrusive on the caribou range. The road itself could be designed to make crossings easier, such as with lower embankments, so that the animals don’t have to climb anything to make it through. And the roads could be closed for dedicated periods when migration activity is highest.  

With the project still in its infancy, the fate of the caribou can still be changed. As their natural habitat becomes ever more fragmented – spurred by industrial operations and a warming climate that affects the vegetation they need – caribou populations, and the memory they rely on, are on a precipice.  

 “If we don’t look after the herd well enough when they’re declining, and we lose most or all of a herd, all that collective memory of the landscape is lost,” Gunn says. “But the herds are still there, and there are still knowledgeable individuals among the caribou there. So, not letting a herd go extinct is really important.” 

Ayesha Habib is a Vancouver-based journalist. 

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