Citizen scientists at Elkhorn Slough Reserve have discovered that sea otters spend a surprising amount of time napping on salt marshes.
Most research on southern sea otters comes from the rugged open coast of California, because they recovered from a tiny population off Big Sur. Elkhorn Slough is the first estuary to be thoroughly colonized by sea otters, and volunteer researchers found they behave quite differently in this ecosystem, in particular hauling out on the marsh for much longer periods than on the open coast, including during the daytime.
This can be enormously valuable for sea otters, which have no blubber and pay a huge metabolic cost to stay warm – it takes a lot less energy to stay warm in the air than in cold water. Hypotheses for the frequency of haul out in the estuary include greater availability of low profile habitat near feeding grounds, lower disturbance by humans, and safety in numbers, as densities are unusually high in the estuary.
There have been few opportunities for scientists to study haul out behavior in southern sea otters, but now the behavior is easily observed due to real-time cameras installed by the volunteer scientists. You can visit our Otter Cams at ElkhornSlough.org/ottercam.
The volunteers happened to start making observations from a hill vantage point, which allowed them to observe otters in creeks from afar, without disturbing them – this discovery, like so many in science, was serendipitous. One implication of the work is that other estuarine marine protected areas, with ample salt marsh and low human disturbance, may provide especially valuable habitat to recovering sea otters in the future.
Download the research from the journal Ecology here. The paper was authored by Elkhorn Slough Reserve volunteers and citizen scientists Ron Eby and Robert Scoles with assistance from Research Coordinator Kerstin Wasson and UC Santa Cruz Researcher Brent Hughes.