Mountains and Marshes. David Rains Wallace
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Boas show their evolutionary age by being the only snakes with such vestigial legs, which they use not to get around but to grip sexual partners.
I once dreamt of digging up a rubber boa so big that it curled all the way around a backyard garden. At least, its head was at one end and its tail at the other: I couldn’t see how much more of it there was, and I couldn’t decide whether to dig up more of it or to start burying it again. There was a sense of danger in this, but also of exhilaration and, somehow, reassurance. This had to do with a series of brilliantly marked birds that landed on a bare sapling in mid-garden and then zoomed away again—a crimson-black-and-white sapsucker, a scarlet-yellow-and-black western tanager, and a black-and-white poorwill. Since poorwills are actually grayish-brown, nocturnal birds that perch on the ground, the latter seemed particularly significant for some reason.
There is a group that I’m not sure about because they are so fast. I may have seen a racer or a striped racer, but all I could see was sinuous bodies slipping through chaparral or grass. I could be pretty sure it wasn’t an Alameda striped racer, a subspecies of the latter, since it is endangered. I did have an impressive sighting of another possible Bay Area member of this group—a big purplish snake called the coachwhip—but not here. It appeared so suddenly before my car at a freeway overpass south of Joshua Tree National Park that there seemed no way not to hit it, but when I stopped and looked, it had disappeared. Harry Greene observed that coachwhips “almost defy the laws of physics at times.”
The snakes I’m sure I haven’t seen are those specializing in the dry habitats of the eastern Bay Area. That is the remotest and most trashed part, between agribusiness, wind and solar farms, and hazardous research or industrial facilities. The best-known arid reptile habitat, Corral Hollow, is the site of a state vehicular recreation area, and then there was the Altamont Speedway from 1966 until it closed in 2008. Having endured the 1968 Rolling Stones concert there, I can testify to its ecological grimness. Even in protected areas like Round Valley Regional Preserve near Brentwood—actually one of the most beautiful landscapes here—local snakes are elusive because arid land species largely live to beat the heat, emerging at night.
There are four such species known here. The California night snake, the size of a garter snake, is the Bay Area’s other poisonous snake, subduing its frog or lizard prey with venom from enlarged teeth on the back of its upper jaw. It’s not dangerous to humans, so it doesn’t have a rattlesnake’s charisma. The California black-headed snake is smaller than the sharp-tailed snake and stays underground more. The glossy snake is a smaller, paler relative of the gopher snake. The long-nosed snake is a drabber relative of the mountain king snake.
If this was PBS Nature, I’d proceed to lecture about how all snakes are threatened everywhere. And it’s true enough in the megalopolis. Even in parks, mountain bicyclists who insist on illegally riding foot and horse trails kill snakes—I’ve found the bodies. Some people deliberately kill snakes just because they don’t like them, which humans probably always have done, reverence or not. Apollo, god of arts and sciences, slew the primordial Great Python, although the corpse just came apart and crawled away to become the local ones of rites and oracles.
. . . a gigantic serpent.
Python by name, whom the new people dreaded,
A huge bulk on the mountain side. Apollo,
God of the glittering bow, took a long time
To bring him down . . .
In memory of this, the sacred games
Called Pythian, were established . . .
—Ovid, Metamorphoses
There are interesting questions as to why snakes are threatened. Much native wildlife has adapted to urban living—mostly birds and mammals but some “herptiles” too. Salamanders abound in gardens; frogs and turtles survive around creeks and ponds; I’ve seen a native fence lizard in my North Berkeley neighborhood. But I’ve never seen a snake—not even the most common or most secretive kind. (Given their slug diet, little sharp-tailed snakes should be welcome garden residents and may persist in some suburban backyards, but not mine.) Cats, rats, and cars must have a lot to do with this. Sun-warmed roads are narcotic for night-roaming snakes. Still, it’s puzzling that a group that succeeds in so many other hostile environments should fail in this one.
Maybe they just need time to adapt. Snakes are slow, comparatively speaking, but so is evolution. Another interesting aspect of Bay Area snakes is that competitive exotic species and diseases don’t seem to have impacted them. Introduced mammals, birds, plants, turtles, and frogs have run riot, but I know of nothing here like the situation with escaped Burmese pythons in Florida, although pet owners must release or lose many exotic snakes here every year. I’ve never seen a feral exotic snake here, anyway. Maybe, where they do survive, native snakes have filled the ecological niches so efficiently that intruders can’t get in.
Civilization certainly has changed the Bay Area in the past two centuries with its wonders like the Golden Gate Bridge. Some say that it has “transformed” the place and proclaim an “end of nature.” That is nonsense. According to probability math, what has lasted longest will last longest. So it’s 100 million years of snakes against five thousand years of bridges. And of course the World Serpent of our blue-green ridges is not always imperceptibly slow in its movements.
Vita longia, ars brevis.
It is a windy December day: the water beneath the rowboat looks excessively cold and briny. With a lonesome awareness of my dependence on land, I turn to see how far I am from it. But I’m not alone: a harbor seal is watching me. On its kelp-colored face is a look of concern; for what, I don’t know, but it is an anxious look of concern. It catches my eye and slips out of sight.
That’s about as much as I see of harbor seals on this excursion. Their distant relatives, California sea lions, are more visible. A herd advertises itself with much barking and waving of flippers. I can row to within a few feet of them, close enough to smell their fishy breath, before they take notice of me, roll their eyes, and dive. Harbor seals usually see me first, surfacing suddenly, and when I get too close, they don’t dive—they just duck.
Not that much is known about harbor seals, although they inhabit coasts from Baja California to Japan and from New Jersey to Portugal. Without particular economic significance, they’ve been left alone compared to other marine “resources” like whales, sea otters, or fur seals. Enough inhabit the oceans to populate a medium-sized city, if the concept applied to them.
The Bay Area has one of the world’s densest harbor seal populations, including a major breeding site, so one might think spying on them would be easy here, as with sea lions. But everything about harbor seals seems to work against that. Sea lions’ glossy fur makes them glitter conspicuously in the water. Harbor seals’ mottled gray-and-tan hair camouflages them. Sea lions are organized: huge crested males dominate females and young on breeding beaches. Harbor seals look alike, and although they are more social than they let on, they are discreet about it. Breeding congregations tend to be cryptic, and the seals seem to do little more than lie around together. Competition among males for females is not conspicuous, although individual squabbling is common enough.
Sizable harbor seal groups often bask on islands in the Bay, but it is not easy to distinguish them from rocks and sand because they lie around in a disorganized way. Sea lions usually bask with their heads toward the top of a reef, but harbor seals may be content to bask head down. It is easier to slip back into the water that way.
Much harbor seal private life goes on in the water and at night. Unlike sea lions, they can mate and give birth in the water. Somewhat paradoxically,