(Sorry, I couldn’t resist…) On an invigorating hike in Annadel State Park, as the afternoon sun shone onto Lake Ilsanjo in the park hills, B. and I heard splashes. A ripple on the water, then three small sleek heads surfaced, long bodies flexing and muscular tails arcing through the water.
I quickly reported our sighting on the website of the River Otter Ecology Project. ROEP research drawing on over 1000 citizen scientist sightings shows that Bay Area river otters, gone for decades, are now back and breeding successfully around San Francisco Bay and the Marin and Sonoma coasts. The first census of Marin County river otters shows about 50 animals along that coastline.
Sadly, research also shows car strikes causing the highest mortality, true for related mammals like badgers. River otters are a sentinel species – their survival shows the effectiveness of local conservation and restoration efforts. This research is the first to show otters’ function in their ecosystem, especially crucial to understand because they’re endangered predators. ROEP’s work involves studying social structure and behavior: how otters use their habitats, bring up their young, interact with other species including prey, and thrive in our watersheds.
Otter mythology is international: the playful animals at home on land and in the water are beloved Caledonian Forest fauna. Scots tales tell of Otter Kings accompanied by seven black otters. If captured, they grant wishes in exchange for their freedom. Otter pelts were also valued for rendering warriors invincible, and protecting against drowning. Celtic and other folklore depicts otters as friendly, helpful creatures sometimes known as water dogs. Ancient Persians also called them water dogs, esteemed above all other animals; anyone who killed them was severely penalized.
Carnivorous river otters eat fish, shellfish, insects, frogs, and small mammals. They also eat water birds such as gulls, coots, and cormorants – especially in fall and winter along coastal waterways – evidenced by feathers in their scat. These warm-blooded animals lack the thick protective fat layer of most marine mammals, so they must consume lots of calories to keep warm in cold water, and keep hunting.
Mothers of young pups hunt and bring prey to their dens. Once pups are old enough to learn to swim, the mothers still fish, but also teach them how to dive and catch their own prey. River otters’ sensitive vibrissae (whiskers) help them fish in murky waters. Pups often nose around each other as they feed, chirping from time to time. Then the mother, disappearing nearby to hunt for a few minutes, swims back to her young, mother and pup nosing, nuzzling, and grunting with each other. Our human connection to these complex mammals is clear in the words of American naturalist Ernest Thompson Seton: “…the joyful, keen and fearless otter; mild and loving to his own kind; … full of play and gladness in his life, full of courage in his stress; … steadfast in death; the noblest little soul that ever went four-footed through the woods.”