Wildlife in the Credit River Watershed
This is part-two in our four-part wildlife spotlight series sharing the exciting news that over the past few years our staff have spotted, or have received reports of four species in the Credit River Watershed that had no previously confirmed records of presence or breeding.
In each edition of this series, we introduce one of the four species so you can learn more about them and their roles within the watershed ecosystem. This week, we’re highlighting the river otter.
Species Spotlight: River Otter
Often confused with the American mink (Neogale vison) or the fisher (Pekania pennanti) highlighted in part one of this series, the river otter (Lontra canadensis) is a member of the mustelid family. Mustelidae, a family of carnivoran mammals, includes weasels, badgers, ferrets and wolverines – to name a few.
River otters are known for their playful nature and adorable appearance. They are dark brown with lighter brown bellies and faces. Their streamlined bodies, short legs, webbed feet and dense water-repellent fur make them excellent swimmers.
Nose to tail, they can be up to 1.4 metres long, with their tail making up about a third of their total length.
River otters weigh between five to 14 kilograms (11 to 30 pounds), with males being larger than females.
You may hear them communicate with whistles, yelps, growls and screams on late night walks. They also scent mark using scent glands near the base of their tails that produce a strong, musky odour to let other animals know they are trespassing on claimed territory.
Where They Roam
River otters prefer a solitary lifestyle and are well adapted for semi-aquatic living, inhabiting and travelling across much of Canada and the United States.
Provided there is enough food, they can thrive in diverse aquatic habitats, including rivers, lakes, creeks and even out of water areas.
Their den building habits, often in burrows claimed by beavers or other similar animals, frequently lead to confusion with North American beavers (Castor canadensis). They can build in natural hollows, such as under a log, or in riverbanks too. Their dens will feature underwater entrances so they can access the water to hunt.
Their breaks from swimming and hunting occasionally include snow play or slides down muddy hills for fun or low-energy travel enhancing their charming nature.
What They Eat
Though cute, these nocturnal hunters will aggressively defend their territory against other male river otters.
Hunting on land is hard enough, but add water and it’s even tricker. To guarantee steady meals, river otters have mastered a range of skills and physical adaptations, including:
- Good underwater vision and long whiskers help them find prey such as fish, clams, insects and other aquatic animals in cloudy waters.
- Flexible bodies and clawed feet help make sharp underwater turns to catch and grab slippery prey like fish.
- Underwater breath-holding, achieving an impressive eight minutes!
Reproducing Populations
Males and females only come together to breed between late winter and early spring. Females give birth to between one and six pups, but usually have two to three, during April or May.
Newborn pups are blind and stay with their mother in their dens for their first month. As they reach their fourth month, mothers will teach her now sighted pups how to swim.
Between 12 and 13 months of age, juvenile otters disperse, often journeying over 160 kilometres to establish a suitable home range.
River Otters in the Watershed
Reasons for Decline
The biggest threat to river otters continues to be humans. Over-harvesting for their sleek fur and water pollution led to a significant decline in their populations throughout the late 1800s and decades beyond that time.
Through conservation management and reintroduction efforts, their populations are now considered stable or increasing.
Recent Sightings in our Watershed
Why do we suspect river otters are frequenting the watershed? Because our trail cameras have spotted them! Perhaps you saw our Instagram reel of some travelling rivers otters captured on camera in the watershed. Here’s more ways were informed of their activity:
- Confirmed otter tracks were found in winter 2020.
- Trail camera footage in 2022 showing two otters interacting.
- Confirmed sightings reported recently in the watershed and other areas along Lake Ontario’s shoreline.
As we do not monitor river otter populations, we have no formal data other than community science or public reports.
Reason for Returning
We can’t say for certain why they are coming back, as their increased activity and population growth likely have various causes. One reason may be that we are seeing the results of the late 1990s reintroduction of river otters to western New York.
Here’s a few ways our work could be helping this species thrive again:
- Habitat restoration.
- Improved water quality.
- Protection of greenspaces, forests and wetlands.
Protect, Restore and Enhance
We study changes to the environment in the Credit River Watershed through our Integrated Watershed Monitoring Program to inform our conservation planning. Explore stories from our data through interactive StoryMaps.
Help report animals and plants in the Credit River Watershed through community science! Submit photo observations to iNaturalist, or if you feel that the observation should be called to our attention, please contact us.
Follow us on Instagram, Facebook and X for more fun nature and wildlife facts.
By Sarah Lebret, Associate, Marketing and Communications.
While fly-fishing in the Credit River in the mid-1980’s just upstream of the Sligo Bridge in Caledon, 2 otters swam past me. They were heading downstream and swam within 6 feet of me while I was wading mid-stream. In all my years of fishing the Credit, it was the only time I saw otters.
Amazing article! Are there any sightings in the Credit River area? Where is Silver Creek?