There's no reason to panic if you see a torpedo shape charging across the pond-unless you're a pond inhabitant.
The pond below our home, in Pomquet, NS, affords a tranquil and ever-changing view. Winter settles in with combinations of graceful ice patterns and swirling snowdrifts, punctuated by dark spots where swift currents keep the water open. When the pond freezes on a windless night, the ice becomes transparent-you can watch tadpoles and insects moving in slow motion under the glassy surface.
Summer has its own set of wonders. Dragonfly males patrol their shoreline territories, scooping mosquitoes out of the air with legs gathered to form a basketball hoop, chasing other males away while they entice females to lay eggs on "their" patch of water. Wood ducks and other waterfowl land to feed in the shallows, dining "bottoms-up." Fish dimple the surface, some jumping for airborne insects. A chorus of green frogs "glump" from the banks. Bitterns occasionally descend to skulk after the frogs, making it tough to be green.
In recent years, whatever the season, a quiet riot erupts on the pond every few weeks. Wanderers within large territories, otters burst onto the scene after an absence, their torpedo shape charging across the water or ice, catching other pond inhabitants off-guard. Ducks flap off the water, fish dart and jump, attempting evasive manoeuvres, muskrats retreat for dens while frogs plop off banks into the water, digging into the muddy bottom. Although the otter's main diet is fish, other small animals learn to pay heed.
The most aquatic member of the weasel family, river otters (Lutra canadensis) have a long, streamlined body that measures from 35 to 52 inches (89 to 132 centimetres) in length, including a tapered tail that's about a third of their total body length-it serves as a rudder for chasing fish. Otters often live for 10 to 15 years, and can weigh from 10 to 30 pounds (4.5 to 13.6 kilograms).
Small eyes and ears positioned high on their head allow otters to see, smell and hear while remaining low in the water. Their ears and transparent eyelids close when they propel themselves underwater with repeated kicks of webbed feet and a serpentine swimming action.
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.
Just before Christmas I woke up to see an otter on the ice beside its hole, dining upon a fine sea-run speckled trout it had just nabbed.
It's easy to trace their activities by observing their tracks in the salt marsh. Traditional scent mounds on exposed points of land are maintained to notify other otters that this territory is occupied. These territorial scat markers are often composed of shiny fish scales, a testimony to the abundance of stickleback and killifish minnow populations in the estuary.
Otters began using this waterway after I spent many years restoring it. The pond area had been a wooded swamp that was converted to pasture many generations ago, and trampled by heavy animals. This was normal land use for the time, and between the mid-1800s and the early decades of the 1900s, the North American river otter all but disappeared across the continent. Up to 95 per cent of wetlands in many regions were drained; the added pressures of trapping, bounties and water pollution spelled their near demise.
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.)
Travelling up from Pomquet Harbour through a salt marsh to the freshwater pond, the otters eventually continue upstream along a brook that serves as a territorial boundary. After visits to two other ponds in the small watershed, they either head off towards a marsh to the west or return downstream.
The otters' short legs create a hump-backed gait through the snow as they travel along stream banks, stopping to inspect open water sites. Sometimes they establish "slides" on steep banks beside the brook, using their bodies to toboggan down inclines. Propelled by their hind legs, they also bound and bodysurf over level snow.
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.