Mountains and Marshes. David Rains Wallace
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minutes or so without awakening. They are generally more adapted to marine life than sea lions, which depend on their fur to keep warm, lacking the blubber layer that harbor seals have in common with whales. Sea lions move about fairly quickly on land because their hind legs turn forward and push them along. Seals have lost that ability.
All this suggests that seals’ ancestors were in the sea longer than sea lions,’ but the fossil record is inconclusive. Recognized sea lion ancestors have inhabited North America’s Pacific coast for about 30 million years, whereas harbor seal ancestors may have appeared here much later. Their ancestors may have evolved elsewhere: there are fossils of harbor seal ancestors from the Atlantic, although they aren’t older than the Pacific’s sea lion ancestors. Paleontologists have found fossils of sea lion ancestors in the Bay Area, at Drakes Bay on Point Reyes, but they haven’t found any such harbor seal fossils. Anyway, both the living genera probably are only a few million years old, not much older than the genus Homo.
Reference to human evolution, of course, brings up the question of intelligence, but harbor seals are no more confiding about this than about other parts of their lives. California sea lions clown in circuses and aquariums as “performing seals,” but harbor seals are not so inclined. When researchers gave intelligence tests to both species, the results were strikingly divergent. Sea lions ran up impressive performance records, while harbor seal records were skimpy. Researchers complained of erratic response, of indifference to the rewards and deprivations that usually stimulate performance. From a behaviorist standpoint, such indifference might not suggest high intelligence. Still, the harbor seals did perform at times, so the researchers concluded that they were at least capable of learning—and very alert, since they spent a lot of time glancing around nervously.
A harbor seal’s brain is larger and more convoluted than a dog’s. Then why is it a bad student? Is intelligence a capacity to learn, or to be taught? Sea lion mothers nurture and instruct their land-born pups until they are ready to enter the water, and teaching continues within the herd at sea. Young sea lions congregate in “schools.” Harbor seal mothers more or less abandon their pups after a three- to six-week nursing period, and the weaned pup gets no special treatment. The mother leaves it with a mantle of milk-fat, on which it lives until it starts to catch fish. Attrition of harbor seal pups is fairly high in the Bay Area’s realm of great white sharks.
Still, there are plenty of seals: their range is expanding where humans don’t persecute them. They seem to be born with survival skills, which would help explain a captive seal’s indifference to a man with a stale herring in one hand and a clipboard in the other. It also might explain their lack of organization: seals don’t seem to need each other as much as other brainy species do. Rich Schopen, a biologist at the Steinhart Aquarium in San Francisco who hand-raised two harbor seal pups, told me that a dolphin or orca would die if kept in a tank alone, but a harbor seal wouldn’t.
One might conclude that harbor seals are poor company. On the contrary, individuals have become greatly attached to humans on occasion. In her book Seal Morning, Rowena Farr describes raising a harbor seal on the isolated Scottish coast. The seal, a female named Lora, preferred to sleep in the author’s bed and developed a passion for musical instruments, including a harmonica, a xylophone, and a toy trumpet, on which she practiced every day and learned several tunes. Farr doesn’t say she taught Lora any of this.
The environmental barriers between the human mind and that of marine mammals like harbor seals are profound. Seals inhabit a world that continually liberates tremendous amounts of energy. Boulders shake as waves pounds them; surf rips through tidal channels. Seals duck under beach breakers like human swimmers but move with ease in currents no human could withstand, the same currents that bring them their food. They lead a double life between land, which may seem strangely ethereal to them, and sea, which must be unimaginably sensual. Bay Area seals inhabit the giant kelp forest, a match for tropical rain forest in its diversity of sights, smells, and sounds—especially sounds.
Harbor seals’ apparent taciturnity is another of their equivocal qualities. Water carries aural vibrations much better than air, so seals’ underwater hearing and vocalizations are complex. Rowena Farr writes: “Seals have perhaps the largest vocal range among mammals. Their repertoire includes grunts, snorts, barks, peculiar mewing hisses, and a wail which often rises from a deep base to a treble.” Under water, they use a special range of clicking sounds that may allow them to echolocate, to “see” by hearing echoes as bats and whales do. They probably can hear tremendous distances, perhaps listening for the sounds of salmon and lampreys moving up rivers, or of orcas communicating with each other far out to sea.
Harbor seals’ visual world may resemble humans’ more than their aural one, but again it’s hard to say. I got a close look at harbor seal eyes when Rich Schopen introduced me to his protégés at the Steinhart Aquarium, and they are strangely beautiful. The iris is an intricate zigzag pattern of gold, amber, and brown—like an abstract Rembrandt—and the pupil is an indescribable shape. It is hard to imagine how such eyes function, although they are set well forward in the head, suggesting good depth and distance perception. Their environment provides them with a lot to see anyway—in both air and water, day and night, vast sandy bottoms and intricate kelp forests.
Henry Wood Elliott, a nineteenth-century seal expert, wrote: “There are few eyes in the orbits of men and women which suggest more pleasantly the ancient thoughts of their being windows of the soul.” Humans living near harbor seals have often associated them with passage into a spirit world. Some believed that seals could come ashore, take off their skins, and live for some time as humans. But that seems anthropocentric to me. With all the unfathomable qualities they have evolved, why would harbor seals want to do that?
—Clear Creek, May 1971
Driving around Oakland’s Lake Merritt is misleading. The lake seems raggedly artificial, a run-down vestige of genteel Victorian landscaping. The lake does have an artificial side. It originated in the 1860s when Samuel Merritt—an early land developer—dammed a polluted tidal inlet to make a setting for mansions like one he was building. High-rises and apartment houses of a certain Raymond Chandler ambience replaced the mansions, although the city turned part of the north shore into a park. Yet a walk around the lake will show that it is not just urban decoration. It is still a working part of San Francisco Bay’s ecosystem, connected by a tidal channel to the San Leandro estuary. Bay waters still ebb and flow in it, albeit controlled by floodgates.
As I write, the first winter storms are passing through, bringing two phenomena that embody Lake Merritt’s connection to the Bay. First, storm sewers drain the summer’s accumulation of litter and grime into the lake, an extraordinary welter of plastic, paper, dead cats, torn underwear—everything imaginable—all filmed with an iridescent engine oil slick that swirls on the lake’s surface. Tides flush some of this out into the Bay and ultimately into the ocean, although the city has to clean much of it. Second, the storms bring flocks of migratory and/or marine birds to the lake, where they feed and shelter for the winter: ducks, grebes, phalaropes, gulls, pelicans, coots, egrets, and cormorants, among others.
But what do the birds eat in this welter of garbage and muck? They eat the products of a rich, functioning ecosystem, albeit a dirty one.
A look into the lake reveals the basic elements. Mingled with Styrofoam cups and Big Mac containers are sheets and strands of algae, the photosynthetic producers at the food pyramid’s base. During the warm seasons, algal blooms fill the lake, breeding disagreeable smells but also many small shrimp and other invertebrates. These feed small fish—mainly smelt and gobies—and they all reach astronomical numbers by October. A look into the lakeshore then will reveal smelt schools that shadow every inch of the bottom with their nervously darting bodies.
Algae, small invertebrates, and bacteria also feed large numbers of clams and mussels, and aquatic worms that live in white, limy cases and filter food from the water with bushy green gills. These organisms hide in the muck or attach to the lake’s stone margins,