Many animal species in the Arctic are highly mobile and travel great distances. Most often they undertake these migrations in search for food. Previously, the most migratory species included the polar bear, arctic fox, reindeer and muskox. But now another prominent species could be added: Arctic hares. Because a study by Canadian scientists on the movements of the animals found astonishing results.
The study by Dr. Sandra Lai and Émilie Desjardin of the Université due Québec a Rimouski (UQAR) showed that the population of Arctic hares they studied in northern Ellesmere Island travel much further distances in summer than previously thought. A female, called BBYY (blue blue yellow yellow) because of her color code, set a new record: within 49 days, the doe migrated a whopping 388 kilometers into the island’s interior and back again. This is the longest known route of an Arctic hare to date and puts previous knowledge of the animals’ migratory behavior in a new light. “When I started studying Arctic hares, I hardly expected the animals to move. And now we have a potentially migratory population.” explains Dr. Lai, the lead author of the paper published in the journal Ecology.
For the study, the researchers fitted 25 Arctic hares with satellite collar transmitters around the Canadian military station Alert, the world’s northernmost permanently populated place, on Ellesmere Island. According to the research team, the goal of the work was to learn more about the potential movements of Arctic hares. Little is known about the hares (which do not belong to the rodent family), which weigh up to 5 kilos and are 80 centimeters tall. Previously, it was assumed that the animals, which live in loose herds, would only move about 1 to 35 kilometers away from their burrows. The results of the study were a surprise nonetheless: three-quarters of the hares fitted with satellite transmitters migrated between 113 and 310 kilometers, with one female hare, BBYY, travelling 388 kilometers, as the team writes in its paper. BBYY moved from Alert to Lake Hazen, the largest freshwater lake above the Arctic Circle, and back again a bit, settling about halfway in November. Then at the beginning of December the doe died of unexplained causes.
Further evidence that the animals are not as site-faithful as previously thought can be seen in the fact that, of the 28 animals color-marked in summer 2018, only two were rediscovered near Alert a year later. Among them was the record holder BBYY. While the research team is excited about the results of the study, they do not yet have a sufficient explanation for the Arctic hares’ unusual behavior. One question is whether this is a local adaptation of Ellesmere Island hares or is more widespread. Second, the results also raise the question of whether the animals follow true migratory routes that have not yet been discovered or are opportunistic nomads in search of food. This is because suitable feeding sites are unevenly distributed, especially in the vast expanses of the high Arctic. According to the researchers, the region around Alert represents a small oasis, but it also attracts food competitors such as muskoxen and predators such as wolves. That is why, according to the authors of the study, it would be interesting to find out whether the benefits of a life on the move are greater than the dangers to which the animals are exposed in the process.
Arctic animals undertaking long migrations is not new, and, thanks to ever-improving satellite technology, amazing feats are coming to light. For example, in 2018, a polar fox that had been fitted with a transmitter traveled 4,415 kilometers from Svalbard to Ellesmere Island in four months. Arctic foxes are about the same size and weight as Arctic hares and are also adapted to life in the icy expanse of the high Arctic. Therefore it seems not improbable that Arctic hares are not the stubby hares they were thought to be for a long time. Future studies will reveal whether BBYY was unique among Arctic hares or formed the starting point for a reconsideration of how their conspecifics live. In any case, the performance of the doe will be immortalized in science even after her demise.
Dr Michael Wenger, PolarJournal
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