North American River Otter - Conservation Success Story

March 19, 2021  •  Leave a Comment

They’re cute, entertaining, charming, and smart. Beyond the species conservation mission, another reason many zoos may keep Otters is because they’re fun to watch and people flock to see them. I was very excited to have a few wild Otter encounters in 2020 and 2021 and wanted to know more about these charming, semi-aquatic mammals. For starters, like so many wild animals, Otter life has not been easy and has its hardships. By the early 20th century, River Otters had been driven nearly to extinction by over-trapping, habitat loss, and water pollution. They disappeared from much of their North American range. However, as habitat conditions have improved over the past several decades, and because of the success of several state reintroduction programs, river Otters are making a comeback.



In March 2021 I was very excited and surprised to encounter a few North American River Otters in a remote lake in West Virginia -- a state where they can still be legally hunted. I observed a pair of Otters engaged in early spring mating. I would never have known the Otters were in this location, except for the constant “duck-like” sound I was hearing off in the distance. River Otters have a mix of vocalizations, ranging from whistles and buzzes to twitters, staccato chuckles, chirps and growls. When threatened or frightened, they emit a scream that can be heard up to 1.5 miles (2.4 km) across the water. After hearing this “duck-like” sound for about 10 minutes straight, I got my binoculars out and could see brown “things” moving about in the water. I viewed through the binoculars for a while and eventually one head appeared above water and I could see it was an Otter. Later in the morning, in a different part of the lake, I photographed another Otter (certainly could have been one from earlier that morning) who spent some time marking his scent -- an important way Otters communicate their presence and status. Otters were once extinct in West Virginia. As part of a reintroduction program, from 1984 to 1997, over 200 otters were released in 14 major rivers across West Virginia. Since then, the West Virginia Division of Natural Resources has determined that the Otter populations are high enough that a trapping season was initiated in 2011 with a limit of one Otter per year.

Conservation SuccessConservation SuccessNorth American River Otter, West Virginia


The name River Otter is a little misinforming. River Otters are not just found in rivers but also lakes, wetlands and ponds if the water quality is good and there's a food supply. In fact, River Otters are an indicator species for water quality and healthy wildlife habitats. Basically, they’ll live wherever they can find food and water to swim in, but they’re sensitive to pollution so they won’t inhabit polluted waterways. Today, North American River Otters live along the Atlantic and Gulf of Mexico coasts, the Pacific Northwest, the Great Lakes, and most of Canada and Alaska. They often live in the same areas as beavers.



In late 2020 I was also fortunate to see wild River Otters in the marshes and wetlands of Huntley Meadows in Northern Virginia. Once word got out that River Otters were in this location, dozens of photographers and hundreds of visitors flocked to this location and enjoyed a few weeks of observing River Otters very close up, in the early part of the day. These Otters eventually moved on or changed their habits because they’ve not been seen at Huntley Meadows since Jan-Feb 2021. North American River Otters prefer minimal human disturbance, and when people are around, they’ll move on or come out only at night or very early in the morning.


Whiz KidWhiz KidNorth American River Otter Whiz KidWhiz KidNorth American River Otter


River Otters are sometimes called "seadogs" which is understandable because they have canines like a dog, clawed (and webbed) feet, and long whiskers which they use to detect prey underwater. Adult river otters weigh 10 to 33 pounds (4.5 to 15 kilograms) and are about 2.5 to 5 feet (76 to 152 centimeters) in length. Females are roughly one-third the size of males. They can seal their nostrils shut while underwater and can hold their breath for up to eight minutes. They eat fish, crayfish, crabs, frogs, invertebrates, snakes, birds, carrion, and occasionally small mammals or birds. Alligators, bobcats, and coyotes all prey on River Otters. River Otters spend a good deal of time on land, and they travel over land, so they become vulnerable to land dwelling carnivores. A North American River Otter's home range can be as large as 30 square miles (78 square km), but a typical territory is 3 to 15 square miles (4.8 to 24 square km). That range shrinks drastically during breeding and rearing season.



While River Otters tend to live alone or in pairs, they socialize in groups and are known for playful behavior. Male and female Otters come together briefly in early spring to mate. Because River Otters experience delayed implantation (meaning that the fertilized egg does not implant in the uterine wall immediately), a female River Otter will be technically pregnant for about a year even though gestation lasts only 5 to 7 weeks. Females give birth to three or four pups at a time, usually between April and May. The young are born blind, toothless and completely helpless, weighing about 4 to 6 ounces (113 to 170 grams) and measuring 8 to 11 inches (20 to 28 centimeters). The male Otter is generally chased away until the young are weaned and old enough to leave their den, which happens about 3 months after birth. After that, the males may return and help raise the pups. Otters remain as a family unit for seven to eight months or until the birth of a new litter. Otters reach sexual maturity at 2 to 3 years of age. If an Otter survives the critical first year of life, it may live to the age of 12, with some surviving longer. The oldest living river otter on record was 27 years old.


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