Can Moose Really Swim? The Science Behind Their Aquatic Skills

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can moose swim
NPS Photo – Claire Abendroth

Moose (Alces alces) are one of the largest land mammals in North America and can weigh up to 1,600 lbs and stand as tall as 6 feet. Given their massive size, and association with watery-habitat, many wonder, can moose swim?

Despite their large size, moose are excellent swimmers. Living and working in Alaska, I regularly see moose wading in water to feed, or swimming across rivers and lakes to access their habitat on the other side.

They are naturally adept swimmers and it’s a lot of fun to watch them swimming across large bodies of water. In summer, it’s not uncommon to see moose wading in the shallow waters of ponds, or swimming across deep northern lakes.

In this post, I’ll dive into the science behind why moose can swim so well.

Can Moose Swim?

Moose are excellent swimmers and are one of only 2 Artiodactyls (i.e., mammals that have an even number of weight-bearing toes) living on land that feed aquatically. The other are species of hippos (Hippopotamus spp.). They even have specialized nasal muscles that help close their nostrils while foraging under water.

NPS Photo

Moose have been observed swimming long distances too. One report found a moose swimming 20 miles offshore, while another found moose swimming between islands that were 20 miles apart!

Why Can Moose Swim So Well?

Moose often live in areas with lots of water given their ties to riparian areas (i.e., areas along rivers, creeks, or lakes). Because of this close proximity to water, moose have evolved to live effortlessly around it.

The two primary factors that led moose to adapt to be such good swimmers are the need to move about their ranges and to access critical nutrients found in aquatic plants.

Moving Within Their Range

Moose live in northern environments in the boreal forest ecosystem. As shown in the picture below, this environment is full of lakes, creeks, ponds, marshes, and rivers.

I have worked as a field biologist in these environments and can attest to the amount of water moose have to deal with in this environment. It is not easy to move around these areas and you’re almost always wading into water up to your hips navigating the terrain.

USFWS Photo

Swimming is a necessity for moose in the boreal forest. They simply need to swim to be able to access resources within their range, whether that’s to find a mate, to migrate to seasonal ranges, or to access forage.

USFWS Photo

One of the first moose I ever saw in Alaska was swimming across a large lake simply to get to the other side. It can save them a lot of energy to swim across a lake rather than having to walk all the way around it.

Feeding

Moose are probably most frequently in the water to feed on nutritious aquatic plants. Compared to foods they can find on land, aquatic plants have higher levels of sodium and iron, and lower fat.

Access to these key nutrients appears to be the main driver of moose to forage on aquatic plants. Researchers believe foraging on these aquatic plants serves a similar function as a mineral lick in summer for moose.

USFWS Photo

Aquatic feeding tends to happen most frequently in early to mid-summer and taper off later in summer. Aquatic feeding by moose during summer can be quite extensive. One study found that 13-27% of their summer diet comes from aquatic plants.

Aquatic feeding tends to happen most frequently in early to mid-summer and taper off later in summer. Aquatic feeding by moose during summer can be quite extensive. One study found that 13-27% of their summer diet comes from aquatic plants.

Predator Avoidance

Moose can also swim to escape predators either by migrating to areas with lower predator pressure in winter or actively fleeing from them.

Pregnant females have been observed swimming to isolated islands to give birth to avoid predators, even though it means they have access to poorer quality forage to support lactation.

NPS Photo

While swimming can offer various protections for moose from predators, not all strategies are always effective. One study documented a moose fleeing a group of wolves by heading into the water and swimming away. Unfortunately for the moose, the wolves caught up to it and eventually killed and ate it!

Summary

So, can moose swim? To say that moose can swim is an understatement as they are highly adapted to living in aquatic environments and some even consider them semi-aquatic mammals.

Moose swim for a variety of reasons, but you’re likely to see them in the water for two main reasons; feeding and traveling.

Here in Alaska, we commonly see moose in the water during summer and it’s always a joy to watch them swim. They make it look surprisingly effortless. And it’s even more incredible when you see a mom with her young swimming just well as her!

Curious to learn more interesting facts about wildlife? Check out my other wildlife information posts.

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AUTHOR
Ryan has Ph.D. in Wildlife Biology with over 20 years of experience working in the field. He has published dozens of research articles in scientific journals and has worked on a variety of animals ranging from ground squirrels to polar bears. He has also been recognized by The Wildlife Society as a Certified Wildlife Biologist.