River otters in the Filter Marsh
By Conservancy Volunteer Bill Rhodes
The Conservancy of Southwest Florida’s Shotwell Wavering Family Filter Marsh has become home to many animals. Fish abound, wading birds visit and feed, and reptiles and amphibians inhabit the marsh grasses.
From the viewing station, you can see many of these — but one of the most enjoyable to spot and watch is the river otter, Lontra canadensis.
The river otter is found throughout the United States, and is remarkably well-adapted for living in water. While they prefer freshwater, they will also visit and stay in slightly brackish water, commonly found upstream in our tidal rivers. They are uniformly brown, ranging in hue from tannish to dark umber. They are quite capable of moving about on dry land, but are most agile and comfortable in water — their short legs have webbed toes and they sport a long flattened tail. Their thick fur is water repellent, and, using their legs and tail to propel themselves, they move gracefully both above and below the water’s surface.
Stiff whiskers jut from their nose and snout, and these tactile hairs are used for locating prey underwater. When they swim below the surface, their ears and nostrils close, allowing them to stay under for as long as 4 minutes, without fear of drowning. They generally grow to be about 11 pounds, with males larger than females, but can reach weights of 30 pounds or so.
It is not uncommon to see them sitting up out of the water, earnestly looking around, to make certain they’re safe from predators (alligators find them a tasty meal), and to spy food. Otters are well known for their playfulness, and are often seen cavorting with family members, chasing and wrestling one another. They are social animals, and this play serves an important purpose, helping participants to bond, and letting younger otters learn necessary skills for chasing prey. You may see them hunting both day and night, and with their active metabolism, they need to eat as much as 15% of their weight in a day.
They feed primarily on crayfish and fish, but will also eat insects, reptiles, amphibians and even small birds. They breed once a year, and litters generally have 2 to 3 young, who stay and feed with their mother until they are about 12 months old. The mother and her young form the nucleus of the social group, and adult males often move away to join groups of other males.
Fisherman aren’t always that pleased to see river otters taking up residence in their local ponds — they can be fairly voracious eaters, and can work together to systematically capture and eat many of the fish there.
The next time you visit the Conservancy, take a walk out to the Shotwell Wavering Family Filter Marsh, and stand quietly. Look for a small, flattened brown head popping out of the water looking about. If you’re lucky, you’ll be able to see a river otter that will, in-between eating and playing, be looking straight back at you.
