Caribou have used the same calving grounds for 3,000 years

Fossils are commonly studied to learn about the history of animals and their behaviors, but sometimes unexpected clues arise. One such example is a recent study conducted by the University of Cincinnati. Looking at caribou antlers from Arctic calving grounds, the researchers discovered that the mammals have used the same sites for over 3,000 years. 

The study was based on the knowledge that Caribou leave behind calving records in the form of their antlers, which they shed days after giving birth. These antlers were sourced from across Candas’ Yukon all the way out Alaska. Some records included antlers from the Bronze Age that have been undisturbed in the Artic tundra for thousands of years.

Study lead author Professor Joshua Miller has been using rafts to navigate remote rivers across the tundra since 2010 when he began leading Arctic National Wildlife Refuge summer expeditions.“To walk around the landscape and pick up something that’s 3,000 years old is truly amazing,” said Professor Miller.

These records represent nature’s longest overland migration, with some barren ground caribou traveling up to 800 miles to reach the Arctic National Wildlife Refuge and Canada’s Ivvavik National Park. It is hypothesized that these areas are favored by caribou due to their lack of predators, the prevalence of seasonal vegetation, and shelter from mosquitoes. 

In addition to helping scientists better understand the calving process of caribou, the study has also outlined the importance of conserving these areas, which have been targeted by energy companies to exploit fossil fuels in the area. “We know this region of the Arctic National Wildlife Refuge has been an important area for caribou for millennia,” said Professor Miller. “That should give us pause on how we think about those landscapes.”

Furthermore, the antlers dropped by female antlers contain calcium, phosphorus, and other nutrients that are important to local ecosystems, creating “nutrient sinks” which could play a local role in the area’s vegetation. Professor Miller suggests that the caribou’s migration could serve as a “conveyor belt” system, bringing the mammals back to this fertilizer in a reinforcement loop.

“We think about having to dig down into the soil to find that kind of ecological history, but on the Coastal Plain, the vegetation grows extremely slowly,” explained Professor Miller. “Bones dropped by animals that lived dozens or even hundreds of generations in the past can provide really meaningful information.”

The findings of the study have been published in the journal Frontiers in Ecology and Evolution. 

Image Credit: Michael Miller

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By Calum Vaughan, Earth.com Staff Writer

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