If you visited the site of my marine education center three hundred years ago you would have found a small spring-fed river flowing through primary forests, emptying into the mouth of Narragansett Bay. Eels, shad and Atlantic salmon swam upstream to spawn at the headwaters of the Mattatuxet River. Like thousands of similar rivers throughout New England, during the industrial revolution textile mills sprung up along the banks, powered by waterwheels built alongside dams created to control and harness the energy provided by the river.
Although disrupting the natural flow of water, small ponds appeared at regular intervals along the river’s path. The eels, shad and especially the salmon, took quite a hit, no longer able to reach the spawning grounds used by countless generations of their ancestors. To other species the creation of these mill ponds was a boon, including perch, painted turtles and river otters.
This mill was built along the Mattatuxet in 1820 by a jeans manufacturer. It was taken over by General Walter Chapin in the late 1850’s to manufacture wool blankets for the Union Army. After the Civil War the mill returned to private ownership, once again to make jeans for civilians. Above is a photo, belonging to a local historical society, of some of the garment workers around the turn of the century.
At this time in our country’s history the river otter was a scarce commodity. Prized for its fur, this member of the Marten family was ruthlessly trapped and shot until their numbers declined to near zero. Otters don’t do well in fast moving waters, so the rise of the textile mills may have inadvertently played a role in preserving this particular species. Historically, otters depended on the services of beavers to dam the rivers for them, but with beavers disappearing nearly as fast, and with natural ponds being drained or filled for agriculture, the few otters that managed to avoid the traps where otherwise hard pressed to find livable habitat.
The dam that built this particular mill pond isn’t very impressive, standing only five feet high. The old cement pilings above is all that’s left of a foot bridge used to cross the river and repair the dam when needed. If you follow the river through the couple thousand acres of secondary forest, the next dam you would find is on the property of the former home of Gilbert Stuart; the guy who painted those famous portraits of George Washington.
River otters (Lontra canadensis) need a lot of room to live and a small mill pond can’t support a very large population. The ones in this pond, as far as I can tell, all belong to a single family. These three above are siblings, born five years ago. I haven’t seen the parents in ages and they have most likely moved on to another section of the river. If you can’t find the third otter in the picture, look closely at the ice edge. He’s the boldest of the three.
Otters are not limited to fresh water ponds. They can also survive in slow running rivers and salt marshes. The two key requirements are food supply and suitable den sites. Otters can’t tunnel very well themselves so must rely on other burrowing or den-making mammals to provide them with nesting sites. Beavers, muskrats and weasels are the most common providers of these dens. The otter will move in once the burrow is vacant.
Although present all year round in our mill pond, these animals go completely unnoticed for most of the year. Their dens are underground on the river bank. During the summer the dens have two entrances, one above the water line and one below. During the winter the upper entrance is sealed closed and only the underwater entrance is used. Dens are made at the base of riverside trees, although in areas where beavers have returned the abandoned lodges are favorite nesting sites.
As a friend and I watched the three siblings across the pond, the brave one swam towards us and emerged halfway across at a break in the ice. Closer to us the ice is solid and the otters use the many breathing holes they maintain in the ice to emerge. During cold spells, when the entire pond is sealed with ice, this seems to be a nearly full-time job.
Another one immediately followed his brother. River otters reach sexual maturity at two years old, so these are well into breeding age. They won’t interbreed so eventually they’ll need to travel up or down stream to search for a mate. These three appear to be content with their siblings as company so perhaps they’ll need to rely on another otter group finding them. When this family was first born there was a fourth sibling, who happened to have been an albino. I don’t think she made it since she was only around for that first year, too young to have moved to another stretch of the river.
Baby otters are called kits and are cared for by the mother for the first six months of their lives. Although the males stick around they don’t really help to raise the litter. After a year, when the parents are ready to start another family, the young are on their own.
Now all three are together, surveying their surroundings and seeming to judge how close to us they are willing to come. Young otters can fall prey to raptors, foxes and coyotes, but an adult otter has no predator save man. For the past couple of centuries the ones that managed to survive were those who learned to avoid human contact. With the hunting threat diminished, at least in my area, where killing them is frowned upon even if it isn’t illegal, the fear of people has waned a bit. Otters are found throughout the United States and Canada and hunting and trapping laws vary from state to state and province to province. Up to ten thousand are killed each year in Louisiana alone.
Our head otter dives back into the water and reemerges at a breathing hole very close to us. He pops up out of the hole and stares at his two visitors, but just as Roberto snaps the photo something underwater distracts him. He dives back into the hole and disappears, his siblings looking on from a distance. Turtles and frogs are wintering over beneath the mud so the diet this time of year is mostly limited to fish.
Otters are at the top of their food chain in the mill pond. Strictly carnivorous, they feed on nearly anything they can catch including fish, young turtles, crayfish, frogs and insects.
Sure enough a few minutes later he appears across the ice with a large catfish in his mouth. Although an otter’s eyesight is very good, this won’t do them much good in the silted water of a mill pond. This is where the whiskers come in. Whiskers can not only sense prey hidden in the mud, but they can also detect energy waves created by a fish moving through the water.
Otters are playful animals, and not in an anthropomorphic sense. They really do spend a lot of time amusing themselves with various games like ice sliding, playing tag and toying with their prey.
While otter number one is busy with his catfish, his siblings decide to try their own luck at hunting. The sight of their brother’s meal seems to make us less interesting for the moment so they both dive back into the water. Otters do not hibernate or become less active in winter, as many local mammals do. The cold and the ice doesn’t bother them at all. The fur is waterproof and the feet are heavily padded. The nose and ears are watertight as well, having valve-like flaps that cover these openings whenever the animal is underwater.
One of the other siblings gets lucky and resurfaces with a sunfish. Otters eat their prey headfirst and although they seem to be unfazed by bones or scales, they don’t like the fins. Walking on the ice, assuming it’s solid enough to hold a person’s weight, you can examine the breathing holes and see dorsal, pelvic and tail fins scattered around the ice. Eating is a messy business and a meal is usually followed by a trip to the river bank where the otter will rub its face in the snow or dirt to clean off the blood and guts from its fur.
Fun Fact: A group of otters is called a "romp".
Except for the one of the millworkers, all photos are by Roberto Julio Bessin.
Other diaries in this series can be found here.