River otters are apex predators in various watershed environments. Typically such dens are makeshift, from log piles or similar natural sources, but often they will use former beaver or nutria dens as well. It is not uncommon for … Otters usually eat fish, eels, frogs, eggs and small birds and are also known to eat small mammals such as mice. River otters possess special valves to seal their ears and noses while they swim underwater. IUCN Otter Specialist Group Bulletin: Prey Preference of the North American River Otter (Lontra Canadensis) Evaluated Based on Optimal Foraging Theory. Otters eat a variety of small aquatic organisms such as … What Do Giant River Otters Eat? River otters may live along rivers, lakes, ponds, sloughs, bays, estuaries or even along a seacoast. A lifelong writer, Dianne is also a content manager and science fiction & fantasy novelist. They sometimes eat aquatic plants. While otters prefer to dine on slow-moving fish (which are easier to catch), they will also eat game fish, crustaceans and mollusks, aquatic reptiles, amphibians, birds, insects, and smaller semi-aquatic mammals as availability dictates. Copyright 2021 Leaf Group Ltd. / Leaf Group Media, All Rights Reserved. They are carnivorous, and most species eat a variety of fish, amphibians, shellfish, crabs, and other aquatic creatures. Mammals include eastern cottontails, snowshoe hares, and meadow voles. A female river otter exhibits delayed implantation of her fertilized egg, so that it will not implant on her uterus for several months. The most common fish consumed are perch, suckers, and catfish. River otters chew their food well, leaving very little waste. However, otters never eat bird eggs. River otters play the role of apex predators, so the river otter food web represents great importance to many watersheds. Mass Audubon is a nonprofit, tax-exempt charitable organization (tax identification number 04-2104702) under Section 501(c)(3) of the Internal Revenue Code. A variety of factors keep beavers inside their homes and out of sight when temperatures drop. This article was featured in the Winter 2020 issue of Explore, our quarterly magazine for members. During the winter, the otters appeared through holes in the ice, then dove down and caught fish and tossed them on top of the ice. But what happens when the water turns frigid and lakes freeze over? They also eat roots, grasses and aquatic plants, and in captivity they even eat leafy greens and mixed vegetables. Embryo Diapause. The local otters fish all winter,the fast water sections of the river stay open so they have no problem accessing dinner! Brown Trout. They hunt singly or in pairs and although otters generally forage in water, they are equally at home on land, sometimes traveling between 10 and 18 miles (16 and 29 kilometers) in search of food. A group of otters wizzes down a muddy slide on their bellies, splashes into the water, then turns and immediately scrambles up the embankment for another go. Sometimes otters work together as a team and scare the fish into small alcoves in the water where they can be caught easily. River otters reach sexual maturity at two years. River otters eat virtually anything that you can find near lakes or streams. Plus, beavers often maintain holes in the ice that otters can use as access points, and their lodges—both abandoned and inhabited—can be used as den sites by the otters. River otters prefer larger fish due to ease of capture; larger prey gives river otters more energy as well. As suggested by its name, the giant river otter is the largest otter species, and it is often referred to as the river wolf . Their impoundments (ponds and wetlands formed by beaver dams) provide a good supply of fish for otters without any additional competition for resources, since beavers are herbivores. River otters breed between late winter and early spring. When ice forms along the edges of rivers, streams, ponds and lakes, local otters climb on top of the ice to eat the fish they’ve caught, bask in the sun and play. Adult beetles and stonefly nymphs are just a few of these. It is always fascinating to come upon their scat (a.k.a. Otters eat a variety of small aquatic organisms such as fish, clams, muskrats, and turtles. Their dark bodies are easier to spot against a white winter … In the wild, they mostly consume non-game fishes, so the competition with game fishers is low. Otters eat lots of fish but also mice and small invertebrates such as crayfish. The trouble with my bright idea is that I can't prove it. Dawn and dusk are the best times to spot a Yellowstone river otter. Anything plant-based is potential beaver food. River otters are strong, unmatched swimmers in their environments, and on land they can run at speeds up to 15 miles per hour. The pups are born blind and spend the first month of their lives in their dens with the female. Mammals. However, otters actively seek out spawning salmon and will travel far to take advantage of a salmon run. Their thick fur made them highly prized for their pelts. If … Young river otters prove to be the most susceptible to predators. They have also been known to eat aquatic plants and to prey on other small mammals, such as muskrats or rabbits. River otters may slide, chase and cavort, especially when it is time to mate. The river otter food chain consists mostly of fish. These pups stay with their mother until autumn. But what happens when the water turns frigid and lakes freeze over? The river otter food web maintains great biodiversity. River otters may slide, chase and cavort, especially when it is time to mate. Sea otters eat about 25% to 30% of their weight. Regardless of its playful nature, the river otter is still a carnivore that feeds on other animals. Otters usually hide and launch surprise, lunging attacks on their prey. Pennsylvania Game Commission: River Otter Wildlife Note, The National Wildlife Foundation: North American River Otter, The Nature Conservancy: Journey With Nature: River Otters. River otters are apex predators in their food web. Make sure to look in areas nearby a body of water. They have a very high metabolism, so they need to eat frequently. River otters (Lontra canadensis) are amphibious mammals known for their swimming ability. How the Otter Half Lives (in Winter) The North American river otter (Lontra canadensis), a member of the subfamily Lutrinae, in the weasel family (Mustelidae), is an equal opportunity player on both land and water. River otters help thin invasive species and protect biodiversity. This species is also considered to be the largest member of the Mustelid family, and this is because these … North American River Otter © Joseph Cavanaugh. These pregnant females seek shelter in dens lined with vegetation. Methods of Collecting Food. A double layer of fur—dense underfur for warmth plus a waterproof outer layer—and a second, clear eyelid allow otters to see and swim gracefully in even the iciest of waters. Today, reintroduction efforts and stricter environmental regulation aid the increasing numbers of river otters. The river otter food web plays a crucial role in the environments the river otter calls home. With a long, muscular body and short legs ending in webbed feet, otters are streamlined for peak efficiency in the water, making them well-suited for a diet of mostly fish, crayfish, frogs, turtles, and other aquatic invertebrates. Why not take a page out of their playbook and get outdoors this winter for some fun in the snow? In higher elevations, deep freezing of waters can force otters to leave the area for lower, warmer elevations, but if all waters become deeply frozen they are capable of traveling long distances over land in search of food. With a long, muscular body and short legs ending in webbed feet, otters are streamlined for peak efficiency in the water, making them well-suited for a diet of mostly fish, crayfish, frogs, turtles, and other aquatic invertebrates. River otters prefer to mate over winter or in early spring, and reach sexual maturity at around two years of age. Social habits River otters are often found in groups. The otters have a finer sense of timing than I can sense. River otters can be found throughout much of the United States, Canada and Mexico around the Rio Grande and Colorado River deltas. They can dive to depths of over 40 feet, all which makes them excellent hunters. poop) on the rocks by a pool and see the iridescent scales of a fish or claws of a crayfish. Life on Land Males are larger in size than females (see photos). Once abundant throughout the watersheds of the United States and Canada, river otter numbers suffered greatly due to hunting by humans. River otters love fish, frogs, crayfishes, crabs, and other aquatic invertebrate creatures. Donations to Mass Audubon are tax-deductible to the full extent provided by law. This mustelid LOVES to have a good time! But they are opportunists, and are … Without river otters, entire watershed food webs would suffer. She spent nine years working in laboratory and clinical research. Birds, their eggs, and small terrestrial mammals are also eaten on occasion. Unlike some other members of the weasel family, the river otter avoids eating carrion (dead animals). In the winter month the Zoo drains the otter pool, but that doesn’t bother the otters at all. The embryos do not begin development until about eight months later, and 50 days after that, the young are born. Although they are able to reproduce annually, it is more likely for this species to give birth every two years. J. Dianne Dotson is a science writer with a degree in zoology/ecology and evolutionary biology. ZIP, ZIP, ZIP. These furry water lovers hunt mostly at night, following the scent of fish even into urban areas. Fish is a favored food among the otters, but they also consume various amphibians (such as salamanders and frogs), freshwater clams, mussels, snails, small turtles and crayfish. Those that have offspring may hunt more because it takes a great deal of milk to feed their young. They can also catch terrestrial mammals such as chipmunks, mice, and young rabbits. River otters eat 15% to 20% of their total body weight each day. They remain active in winter, using ice holes to surface and breathe. They have loads of fun sliding down their slopes and playing with the novel items hidden in their exhibit by the zookeeper. The otter uses its sense of sig… Adult otters weigh 10 to 30 pounds and can grow up to four feet long, while baby otters are typically half their size. Young stay with their mother through their first winter. The Red River Zoo is home to two otters, Annabelle and Butler. As the seasons turn colder, beavers carefully store food near their dens to prepare for bad weather. They will feed on fish, invertebrates, frogs, clams, crayfish, and small mammals or birds. Food. The cubs will remain with the parents through the first winter, but separate the next spring. They may even dig up hibernating turtles or frogs from the bottom of the pond. But they are opportunists, and are known to capture bigger creatures such as ducks. •They appear to have a real fondness for sliding down steep mud, snow, or ice-covered banks. The brown trout is a medium-sized fish that lives in lakes, rivers, and streams, and it … A female Otter can spend up to 8 … In an area with river otters, it is common to see a pattern in the snow left by the otters. Favorite foods include fish, frogs, crayfish, snakes, turtles, amphibians, birds and small mammals. River otters possess long, muscular bodies suited to their life on both land and in water. Their high metabolisms result in rapid food digestion. River otters reach sexual maturity at two years. They primarily eat slow moving fish like suckers and catfish. River otters are smaller than their cousins, the sea otters. While beavers don't hibernate in winter, they are less active and people spot them infrequently. 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