“Otterly” Awesome! Land Trust hosts river otter presentation
— Created November 18, 2020 by Kathy Reed
By Melanie Hammons
Now you see them, now you don’t. That just may be the most descriptive phrase you could apply to the North American River Otter, according to Dr. Heide Island, professor of Comparative Animal Behavior and Neuroscience at Pacific University. Island will give a free informational presentation on the creatures via Zoom at 6 p.m. Friday. The event is being hosted by the Whidbey Camano Land Trust.
Born and raised in Alaska, Island said the two things that drew her life-long interests were marine systems and marine mammals. In school, she very much enjoyed field work. By the time she became a full professor, she knew river otters were where she wanted to focus her research.
Island has devoted the past two years to the study and research of these elusive residents of Whidbey Island. Interestingly, she says the name, “river otter,” is a bit of a misnomer on Whidbey, which, though it’s surrounded by water, has no rivers of which to speak.
But the island is brimming with estuaries, lakes, wetlands and ponds; there’s a mix of saltwater and freshwater environments. And those features are key to explaining why the river otter’s appearances can seem so elusive and fleeting, said Dr. Island.
“River otters display a coastal preference, but they thrive in both healthy marine and freshwater settings,” she explained. “They are amazingly adaptable, capable of moving quickly from fresh water to salt water.”
In other words, there’s more than just shyness driving their behavior. Dr. Island offered some metrics to prove just how quickly they can switch locales.
“They are able to move between marine and freshwater environments within two minutes. They are mission-oriented (finding food,); if one feeding patch has scarce resources, they lose no time in moving on,” she said.
That adaptability trait impacts more than just their food choices. It turns out they have a very good reason to seek out freshwater sites exclusively from time to time – they need to clean and groom their coats; for that, only fresh water will do.
The river otter’s successful dual-environment adaptation engenders an even greater appreciation when one considers the inherent differences that exist between marine and freshwater settings, said Dr. Island.
“This documented movement, from freshwater to saltwater, then back again, means they are constantly moving from water with very little buoyancy, to saltwater, which has a great deal of buoyancy,” she said. “Not to mention the temperature shifts that are involved as well. And their navigational skills enable them to successfully forage even when the water has low visibility.”
Studying river otters yields far more valuable information than most people are aware. The North American River Otter is considered a “bellwether,” or indicator species, said Dr. Island.
“We’ve learned many details affect their foraging patches – salinity, currents and tides, seasons, and time of day all have a role to play. And it goes beyond that.”
“Lately, there’s been much concern expressed about the health of Puget Sound in general, and local waters in particular,” Island continued. “By studying how well these resident river otters fare, questions are answered. Light is shed on issues dealing with water systems and other animal species like salmon, rockfish, and Ling cod. In regard to declining salmon counts, for instance, does the river otter’s diet play a significant role? No. It turns out the otters dine mostly on flatfish.”
Volunteers and citizen scientists have supplied her with a wealth of river otter information on behavior and distribution. Often, it’s as simple as people just reporting sightings. Others host trail cameras on their property. Island said her findings would be woefully incomplete without their help.
“I’ve been fortunate. First, Whidbey Islanders are very welcoming and accommodating to scientists. But secondly, with the pandemic restrictions, I’ve been unable to do as much research with university students as I normally would. So the call-ins and trail camera recordings have given us an especially welcome boost in a most unusual year,” she said. “My website gives more information about ways volunteers can participate.”
North American River Otters enjoy a broad range across the United States.
“They don’t have many natural predators, and the population here on Whidbey seems stable,” said Dr. Island. She has a few helpful tips for people hoping to catch a glimpse of river otters in the wild. Early morning seems to offer the best chance of viewing but river otters may be seen at any time of the day.
The best way to differentiate between sea otters and river otters?
“Sea otters always float on their backs.” Island explained. “River otters float belly down. I’d describe their appearance as they move through the water as almost snake-like.”
And they can move quickly; Dr. Island said her average viewing window of river otters is about eight minutes.
It would seem the unique combination of marine and freshwater worlds gives great advantages to river otters here. Even with “no rivers,” Whidbey has still proven to be a good home for the North American River Otter.