Otters appear sweet and playful as they glide through the water, flip on their backs, and enjoy their water habitat. However, they can be aggressive hunters when it comes to food.
Otters primarily eat fish but will eat other prey, including ducks. Otters have a high metabolism to thermoregulate their bodies in the water. As a result, they have high caloric needs, consuming 15% to 30% of their body weight each day. Otters will feed opportunistically, grabbing ducks from underneath the surface and biting their necks, or will pull them repeatedly underwater until they stop struggling.
Read on to learn more in greater detail about what otters eat, why they eat so much, and how they catch prey.
What Do Otters Eat?
There are 13 species of otters, belonging to the Mustelidae family, found in aquatic areas such as freshwater wetlands, lakes, and rivers or marine and ocean waters.
Otters are carnivorous opportunistic feeders. However, they will also consume small amounts of plant food, especially if food sources are low while they search for meat.
They are predators at the top of the aquatic food chain, feeding on many types of prey.
A study of their feces shows that otters primarily consume a large diet of fish, but will hunt and eat other prey such as crustaceans, mollusks, snakes, ducks and other birds. They also will eat crabs, crayfish, frogs, reptiles, and small mammals such as muskrats and rabbits.
Why Otters Eat A Lot: Thermoregulation And Metabolism
Since these water mammals spend a large part of their day in the water, they can lose body heat quickly.
Heat transfers from the otter’s body to water much faster than it would in the air of the same temperature.
As a result, otters have a significantly higher metabolic rate than land mammals of the same size in order to stay warm enough while in the water.
Therefore, this higher metabolism requires that the otter takes in more calories, driving its need to feed more frequently. Depending on the species, otters will eat 15% to 30% of their body weight daily.
Otters do not have a layer of fat like other water mammals, but warm air can trap in their dense fur, helping them to stay warm.
Otters also groom themselves to help the fur stay in place. Grooming helps to keep the air trapped in place, making an insulating layer of interlocked hairs.
This keeps the air in and the water away from the underlying skin. Pollution, such as crude oil, can affect the otters’ fur, potentially leading to hypothermia.
Otters can be seen floating on their backs with their feet poking out of the water. This helps them to reduce the amount of heat loss, as their feet absorb radiant heat.
How Otters Catch Prey
Otters have sensitive paws and whiskers and sharp canine teeth and claws, using keen vision to methodically search for food.
They are agile and strong creatures that dive under the water and grab their prey.
Their powerful jaws can break through prey’s bodies, and they utilize tools such as rocks, driftwood, or manmade objects, such as bottles, to also break prey open on their chests as they float.
Otters will carry their tools and prey in the loose folds of skin underneath each foreleg.
The need for food may result in otters stealing food from each other, or holding pups “hostage” until the parent otter has given up their food in exchange.
Otters will completely eliminate their habitats of food sources, especially if it is a closed system, such as a lake without fish replenishment.
If food sources become scarce, they will turn to other prey for food or move to a new water location.
How Otters Catch Ducks
If ducks, and other birds, are on or near the water, otters will hunt them as well. Domestic ducks with clipped wings and ducklings are an especially easy target for otters.
Otters will swim up underneath a floating duck or duckling, and grab its legs or neck. It may eat it while it is alive and struggling.
Or, they may capture the bird by grabbing it and then repeatedly pulling it underwater, while biting it, until it stops struggling.
Once the bird is deceased, it will chew the desirable parts of the bird such as the breast, neck, and legs.
Eating birds demonstrates that the otter’s diet is versatile, beyond the scope of aquatic creatures only. Researchers theorize that otters may eat ducks and other birds if they are ill or injured and unable to dive as frequently, or if there is a lack of other food sources.
Otters need to eat a lot to sustain energy to thermoregulate and feed their high metabolisms.
While otters primarily eat fish and other small aquatic creatures, unsuspecting ducks are grabbed by otters, pulled underneath the water, and consumed.
To thrive, otters eat 15% to 30% of their body weight each day, and ducks are an option to otters in providing an essential source of food.
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