Ludovic Landry-Ducharme, an Arctic hare researcher, guides us through all the things we do not – yet – know about the world’s most northern critters.
It is that time of the year. The time when shopping malls and supermarkets alike blossom with chocolate eggs, baskets full of candy, and, last but not least, bunnies.
The hares and rabbits that pop-up everywhere during Easter have become so ubiquitous that we take them for granted. But why is the Easter Bunny, presumably a mammal, so obsessed with its eggs? And what is the connection to the death and resurrection of Jesus?
The Easter Bunny is clouded in mystery, and in the Arctic, a brethren of the Easter Bunny is the source of similar wonderment: the Arctic hare.
Because as Ludovic Landry-Ducharme, a PhD-student at the University of Quebec, explains, there are several questions about Arctic hares that are as yet unanswered. Some of them he and his colleagues are trying to solve through a multi-year research project on Ellesmere Island, Canada’s northernmost island.
A few years ago, this research project led to the discovery that Arctic hares are much more migratory than expected. But this migration is itself a source of mystery.
Read Ludovic Landry-Ducharme’s five biggest unanswered questions about the Arctic hare below.
1. How they live during winter
“What do we know about the life of Arctic hares during winter? Pretty simple: not much.”
“We know a little from the most southern populations in Newfoundland, but about the ones we are studying on Ellesmere Island we don’t know anything. That’s what we want to explore.”
“How do they adjust to such harsh environmental conditions: low food availability, freezing weather, predators, an Arctic desert, and eternal darkness in the polar night? These are very tough conditions to live in.2
“We want to learn more about this so we can compare it to the strategies of their southern lifestyle, and maybe compare it to strategies of bigger animals in the same ecosystem that we know more about,” Ludovic Landry-Ducharme told Polar Journal.
2. Why their migration patterns change
“Before 2019, we thought that Arctic hares, like most herbivores, were a resident species, meaning that they stay in the same area all their lives. But then we discovered, as described in our journal article, that they can do very large scale movements over hundreds of kilometers.”
“This was unbelievable because a lot of theoretical work suggested that the Arctic hare would be too slow for that; that it is so slow that it would be too energy and time costly to migrate like that. But it did happen.”
“However, last year, we discovered that the movements we saw in 2019 didn’t happen to the same degree this year. This is a very new observation that we are still not sure how to explain.”
“We believe that it could have something to do with population cycles. The classic example is the snowshoe hare whose population size grows and crashes all the time. So maybe they don’t need to migrate to the same degree when their population size isn’t as large.”
“But all this is still unknown,” Ludovic Landry-Ducharme said.
3. How sex differences lead to different summer lifestyles
“A lot is unknown about the sex differences in the Arctic hare.”
“First, what is known: The Arctic hare is a polygynous species, which means that one male mates with many females. This means that males and females have different mating strategies; the male looking to mate with as many females as possible, while the female prioritizes the survival of its offspring.”
“This difference might lead to very different summer lifestyles. This may also depend on their energy constraints, and their constraints in movement, and this could help us interpret where they go during winter.”
“Because we do know that there are more of them in the summer than during winter. In the spring, we see lots of them arriving but we don’t know where they come from. It is part of their behavioral ecology that we don’t know much about,” he said.
4. How old they get
“The literature is pretty vague on the lifespan of Arctic hares. It estimates two to five years, but we don’t know anything for sure.”
“In our project, we tag the hares so we can identify each individual. If we see the same hare over multiple years, it will give us some idea about how old they get. Especially if it was a juvenile when we tagged it.”
“But still, this individual has to survive, which is a challenge for the species. Their strategy is to make a lot of babies because there is a lot of mortality.”
“For Arctic hares, it is rare to die of ‘natural causes’, unless you count predation (being eaten by predators) as natural causes. They might also die from starvation or from the cold, but we don’t know yet.”
“All this makes it difficult to determine their lifespan. And moreover, we still haven’t spent many summers with them,” Ludovic Landry-Ducharme said.
5. How they will adapt to climate change
“For now, we are still at the stage of describing their lifestyle and behavior. This will give us a baseline to assess how the changes from climate change will affect them.
“Climate change could possibly affect their environment, their behavior, and their population status. There might even be some benefits to them if climate change leads to more vegetation in the Arctic, and thus more food.”
“But I can guess one thing could become a challenge for them in the future. The Arctic hares on Ellesmere Island stay white all year long, as opposed to the more southern subspecies who become brown in the summer.”
“Currently, there is snow all year round, so even in the summer they can hide in snow patches with their white fur, and the fact that they don’t have to change color saves them some energy. But with climate change, if all the snow becomes less present during summers, it could affect them in a major way,” he said.
Ludovic Landry-Ducharme and his colleagues plan to return to the Canadian High Arctic this summer. Hopefully, if things go according to plan, they will get one little bunny-hop closer to finding answers to all the questions that surround the Arctic hare.
Ole Ellekrog, Polar Journal
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