If you’ve ever been lucky enough, you may have seen a moose swimming.
Its antlers and head rise above the surface, while its legs work beneath the water.
"They almost walk through the water, similar to how a dog swims," Erling Johan Solberg tells Science Norway.
He is a senior researcher at the Norwegian Institute for Nature Research (NINA), specialising in moose, among other things.
Solberg explains that moose are known to be excellent swimmers.
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"They mainly use their front legs, more than their hind legs," he says.
Swims better than other large mammals
There are many large mammals that can swim, but both size and physique can make it difficult for them to manage long distances or rough sea conditions, Solberg explains.
Moose cope better. They are capable of swimming long distances.
There are numerous observations of moose swimming in challenging areas, for example far north in Canada, according to the news outlet CBC.
Illustration photo of a swimming bull moose.(Photo: Wirestock Creators / Shutterstock / NTB)
Swam more than eight kilometres in one stretch
Solberg took part in a study of how moose live on and around the island community of Vega in Nordland, Northern Norway. You can find the report here.
Researchers fitted a number of moose with GPS transmitters to track where they move and where they are at different times of the day and year.
And where they swim. And that can be far.
One moose cow swam more than eight kilometres in open sea in a single stretch. She swam several long stretches in the sea while the researchers tracked her.
This is how the female moose moved on Vega. She crossed long stretches of sea.(Image: NINA)
Erling Solberg doubts that the moose swam that far in one continuous stretch, but we will return to that.
This is in the sea, where there can be wind, ocean currents, and waves. If you have ever tried swimming in the ocean, you may have felt how much effort it takes to work against the movement of the sea.
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The moose cow crossed several longer sea stretches, as stated in the report. She used these swims to migrate from Vega to the mainland.
Does it depend on where the moose comes from?
Solberg points out that not all moose seem equally fond of swimming – it may be related to where they live and grew up.
He believes moose from inland areas might not attempt long-distance swims in the sea.
"It's probably primarily moose born in this landscape that are adapted to moving in the water," he says.
And this brings us to why they swim so far. Despite the danger.
Moose in Finnish forests.(Photo: ArtBBNV / Shutterstock / NTB)
Dangerous journeys
"It can be risky in many situations," says Solberg. "We've found some dead moose drifting in the sea. Some have ventured into things they couldn’t handle."
So a moose can put its life at risk when it sets out to swim. Even so, these journeys also offer clear advantages.
"It's probably so skilled at swimming because it's a highly useful adaptation for a large animal that needs to get around," says Solberg. "Deer species are generally strong swimmers. Reindeer and moose may be the best equipped, as they have thicker fur and relatively large bodies."
These animals are adapted to cold climates, which also benefits them in the water. Their fur is made up of air-filled hairs that help them float, according to Solberg. These hairs also provide extra insulation.
A moose can therefore cross small straits or rivers with relative ease. But it may also embark on far more dangerous and longer journeys at sea.
Why does it do this?
Inbreeding and migration
Moose are able to swim long distances to move away from other moose, particularly in coastal regions.
Solberg explains that it can be beneficial for moose and other animals to leave their family once they reach adulthood. This helps prevent inbreeding – that is, close relatives mating with one another.
For moose living along the coast, swimming may be necessary to reach new habitats and introduce fresh genetic diversity.
It may also be linked to competition for food and population density.
"It's a major advantage to be able to move away from an area where there are many moose," says Solberg.
For example, by crossing a strait to reach an island.
Moose may also swim to islands to keep themselves and their offspring safe.
"Some make strategic use of small islands during calving, when the calf is at its most vulnerable. They may remain on small offshore islands for a couple of months, until the calf is better able to escape predators," he says.
So there are many reasons why moose take to the water, but how far can they actually swim?
40 kilometres?
With the help of GPS tracking on Vega, researchers know that moose can swim eight to ten kilometres in the sea. But are they capable of going much farther than that?
"Moose have a tendency to appear in the most unexpected places along the coast," says Solberg.
A moose appeared on Træna in 2005, which is about 40 kilometres from the mainland in Nordland. But did it swim the entire way in one stretch?
Solberg believes that is unlikely.
The distinctive mountains on Træna. Is this what the moose saw?(Photo: Beata Milewska-Marecka / Shutterstock / NTB)
He points out that there are islands and skerries along the route where the animal may have stopped to rest. According to Solberg, moose are often observed just before or shortly after they arrive, so their exact route is usually not known.
He adds that GPS tracking makes it possible to get an overview of these swimming routes, as shown on the map above.
But many questions remain unanswered. Researchers do not always understand why moose take to the water, according to Solberg.
He says that even when moose live in areas with favourable and safe conditions, they may still migrate and head out into the water.
There may be an inherent urge to set out and explore the world, Solberg tells Science Norway.
At the very least, younger moose are known to embark on long journeys, even at sea.
