California sea lions and northern elephant seals are seen on Sonoma’s Pacific Coast, but Jenner’s rookery attracts mostly Pacific harbor seals. Each spring a large sand spit builds up in Jenner, right at the mouth of the Russian River. The spit provides an ideal rookery – an area where seals feel safe to give birth, rear their pups, and forage for food.
All summer long the spit is crowded with adult harbor seals and their frisky youngsters. When they’re not barking at each other they stretch out in the sun for hours, and every now and then they wiggle awkwardly on their bellies across the sand and into the water. The playful pinipeds are fun and fascinating to watch and tend to draw crowds.
However, though they appear sweet and fun-loving, never forget that seals are wild animals. Harbor seals are strong, fast-moving and unpredictable (especially those protective mama seals). Enjoy watching them play, but for safety’s sake stay at least 50 yards away.
On a typical day, Pacific harbor seals spend about half their time on the sand and half in the water. They tend to forage at night and rest during the day. When foraging for food, they can dive as deep as 1,500 feet and stay submerged, according to the Marine Mammal Center, for as long as 40 minutes. Most dives, however, average about three to seven minutes.
Here are some facts about these Pacific harbor seals that will make your observations fun:
Size: As adults, they can weigh as much as 300 pounds and reach six feet in length. Unlike many other types of seals, male and female harbor seals aren’t much different in size.
Mating and Breeding: A single pup, weighing 20-24 pounds, is born to a female between February and April. Pups can swim at birth, and take about four to six weeks to be weaned. Adult females mate and give birth each year.
Food: As you’d expect, seals are big into seafood. They particularly enjoy sole, anchovy, herring, flounder, sculpin, hake, cod, octopus, and squid.
Aside from pinipeds, the Russian River spit is also a major resting spot for various species of coastal birds. Among them are brown pelicans (considered a “Bird of Special Concern” under the Endangered Species Act), and Heerman’s gulls (protected under the Migratory Bird Treaty).