River otters are found in the wild throughout Nova Scotia. … River otters have dens on land in which to sleep and have their babies. They have few natural predators, especially while in the water, but coyotes and wolves will hunt otters on land. River otter lifespan is 5-8 years in the wild.
Diet: Carnivores, eating mostly fish such as minnows, perch and trout, river otters will also eat other aquatic items like clams/mussels and crustaceans, as well as frogs, muskrats, birds (particularly young waterfowl), eggs, insects and even turtles.
Life Cycle: River otters mate in early spring but due to delayed implantation do not birth their young until almost a year later. The fertilized eggs do not attach to the uterus or begin to grow until late winter. A litter of 1-6 young (kits) is born in spring, which is followed by adult mating season. The young are born blind and helpless, though they have fur. Their eyes open at 35 days and at around 2 months old they begin to swim. Young otters spend the summer with their mother, learning to hunt before they are ready to be independent in the autumn. River otters have dens on land in which to sleep and have their babies. They have few natural predators, especially while in the water, but coyotes and wolves will hunt otters on land. River otter lifespan is 5-8 years in the wild.
Adaptations: River otters are well suited for their semi-aquatic lifestyle. They are streamlined with waterproof fur and webbed feet to help move quickly and easily through the water. Valves in their ears and nose keep the water out and clear third eyelids protects their eyes and allow them to see underwater. Specialized lenses in their eyes also increase the otter’s vision in murky water, plus sensitive facial whiskers aid in maneuvering underwater. River otters keep holes open in the ice so they can remain active through the winter without getting trapped under the ice. Their oil-insulated fur keeps their skin warm and dry in cold water. River otters are very sensitive to pollution as polluted makes their fur less waterproof, and can severely limit food sources.
Otter in the Water!
BY BOB BANCROFT in Saltscapes
Otters can travel hundreds of metres submerged, remaining there for as long as four minutes. They chase fish visually, but use stiff, sensitive whiskers to locate animals like frogs hiding in the bottom.
They breed in the spring; two or three young are usually born the following spring. Sometimes whole families arrive at the pond. Otters can be playful, and routinely sunbathe on the dock.
In winter, they leave telltale pairs of paw prints and a tail drag on the snow around the edge of the pond. Rough knobs on their rear heel pads give traction on ice. Otters hunt the open water areas of the harbour for both fish and ducks. Excavating a hole in the thin pond ice along one shore, they continue to pursue fish underwater.
As fish-eaters, animals like loons and otters tend to accumulate heavy metals that are present in the aquatic food chain. A 1996 otter study in southwestern Nova Scotia found mercury levels of inland river otters to be 10 times higher than river otters living along the coast. (Along the East Coast we don’t have sea otters, just river otters that also use the sea.)
Otter tracks in the snow have sometimes gone off into woods, away from the brook. Were the otters searching for hollow logs to use as den sites and sanctuary from roving predators like coyotes and bobcats? Because this forest had grown on land once cleared for pasture, there were no old trees with cavities on the forest floor.
With help from a forestry contractor, I scattered big, hollow logs throughout the woods. Branches and other woody material were piled around the logs to hide them. With time, otter and mink began to appear more regularly.
One day I watched an otter dragging a large tree branch out of the pond, depositing it on the bank. I remembered an instance when I had watched four otters collectively herd a school of fish into a shallow area of the pond. Once cornered, the fish were easily caught.
Tree limbs might interfere with that process, allowing fish to escape. Was the otter making sure that the limb wouldn’t get in its way?
Later in the summer I strapped some large tree limbs together, weighted them, hoisted the entire affair on a sheet of plywood and loaded it on a canoe. Paddling out to where the water was 10 feet (3 metres) deep, I slid the brush pile off the gunwales and over the side, watching as it slowly disappeared into the murky depths below.
Placing hollow logs on the forest floor for otters had reminded me that fish, in turn, need hiding places. Life can be a delicate balance.