The best thing about paddling around a farm pond or shuttling off to a stream — especially in spring — is all the cool things you’re likely to see while you’re out on the water. Frogs and turtles splashing into the soup, silvery fish flashing below your boat — hold on — what’s that furry critter sliding down the bank and into the water? It could be one of several aquatic mammals that call Missouri home.
Warm-Blooded, Fur-Covered Water-Lovers
The science-y phrase, “aquatic mammal,” basically means “furry, warm-blooded critter that makes itself at home in the water.” Mammals that live near but not in the water are called “semi-aquatic.” This could include humans, too. Some river-loving people call themselves “river rats.” Are you a river rat? Whether they live in bank-side burrows or just hunt from the bank, Missouri’s aquatic and semi-aquatic mammals are all good swimmers. Some share similar features like webbed toes or “swim goggle” eyes, and others have scaly, oarlike tails. Let’s get to know each critter and find out when and where you’re likely to see them.
Built for working underwater
Clear “swim goggle” eyelids, closeable noses and ears, and sensitive whiskers help otters and beavers navigate in the water.
Otters and beavers come with their own layered wet suits that keep them warm, even under the ice. They start with an insulating layer of fat under the skin. Then there’s a short, thick, oily layer of fur next to the skin. And on top of that, there’s a glossy coat of guard hairs.
Webbed toes, tapered bodies, and oarlike tails help otters, beavers, and muskrats move like acrobats in the water.
North American River Otter
These aquatic clowns are well-suited to life in the water. They have sleek, streamlined bodies and fully webbed feet. Their long, tapered tails are thick at the base and flat on the bottom. Their ears and nose close when they go underwater, and they can stay under for three to four minutes. They have lots of sensitive whiskers that help them find crayfish in the water, even at night. Although they are mostly nighttime hunters, they’re active all year. You may see one (or several) sliding down a snowy or muddy bank — splash — right into the water! The name “river otter” tells you where you’re most likely to see them.
Minks and otters are cousins. You could think of them as water weasels, although the mink is less aquatic than the otter. It lives in margins between water and woods under tree roots and logs or in old, bank-side muskrat burrows. Like the otter, it works the night shift, and it tends to keep to itself. Still, you might see one (or a young family) hunting in daylight this spring or summer. They’re fast runners as well as good swimmers, and they’re known to eat young rabbits as well as fish, crawdads, and even ducks. They often stash their food in their dens to eat later.
These medium-sized water rodents dig burrows in pond, lake, and stream banks, or they build big dens out of sticks and cattails in marshes and wetlands. While otters and minks mostly eat meat, muskrats are mainly plant eaters. In marshy areas, they eat the roots and stems of cattails, rushes, and lotuses. Muskrats living along Ozark streams will eat mussels, snails, crayfish, and frogs as well as water plants. When swimming, the muskrat’s slim, scaly tail paddles back and forth, almost finlike, behind it.
The beaver is Missouri’s largest aquatic mammal, and a big one can be 54 inches long and weigh 90 pounds — probably bigger than you! Unlike muskrats, which have long tails, the beaver has a broad, flat tail that serves as an all-purpose tool. In the water, it works as a rudder and a propeller. On land, it serves as a kickstand to help the beaver balance on its hind feet while it chomps down trees. Like muskrats, beavers build lodges, where they sleep and raise their families. While muskrats make their lodges out of cattails and rushes, beavers build theirs out of sticks, branches, and logs. Either water rodent may also make a home by digging into a stream bank. Unlike muskrats, beavers never eat meat — only bark, twigs, pond lilies, and other plants. Both critters have special lips that close behind their teeth to keep water from flowing into their throats as they swim with branches or cattails in their mouths. Beavers are mostly active at night, but it’s possible to spot them just before sundown in the evening or just after sunrise in the morning. If you’re lucky, you may see a beaver sunning itself or using its hind toes to comb oil through its fur. A Sure Sign If you find pointy tree stumps along a stream or lake, you can bet they’re the work of a busy beaver. To spot a beaver’s lodge, scan the water for a heap of branches or look for a burrow dug into a stream bank.
These masked mammals aren’t aquatic, but they do like living near water. They swim as well as they climb, so they’re just as likely to splash in the water for mussels and crayfish as they are to reach for tasty blossoms, mushrooms, and fruit. Like most of the float buddies profiled here, raccoons are creatures of the night. They start prowling for food around sundown, so you might spot a ring-tailed shadow slipping along the stream near the end of your day on the river.
OK, NOT a native aquatic mammal, but a true water dog — and a Missouri river rat’s best friend. Don’t be surprised if one paddles out to say hi when you float by.