CURRENT ISSUE

SUBSCRIBE

CONTACT US

ADVERTISING

SEARCH

BACK ISSUES

CONTRIBUTORS'
GUIDELINES

THIS WEEK IN
CALIFORNIA WILD

habitats

Alameda Whipsnake Hanging On By Its Tail

Gordy Slack

Deep in separate burrows on a hillside a few miles from my north Oakland home, two Alameda whipsnakes wait for the winter rains to end. They are too cool to move a muscle; just as cool, in fact, as the chilled, compacted dirt on which they lie. But in the spring, when the warming morning sun thaws their torpor, quick movements will define them, setting them above all the competition in their hunt for the fence lizards that are their favorite prey.

If they're lucky, in the spring these two snakes will find each other and entwine their sooty-black and orange striped bodies, he pressing her broad, large-eyed head repeatedly down in the hour-long joinings they may perform several times over their few days together.

And if their luck holds out, their half dozen or so offspring may survive the season's marauding raccoons, possums, California kingsnakes, striped skunks, coyotes, foxes (both the native gray and the introduced red ones), feral cats, and hawks that all ignore the federal government's prohibitions on "taking" threatened species.

Last December, the U.S. Fish and Wildlife Service boosted the Alameda whipsnake's (Masticophis lateralis euryxanthus) chances of surviving the next century by adding it to the federal endangered species list, making it the second Bay Area snake--along with the San Francisco garter snake--to belong to that dubious club. The 30 or so known Alameda whipsnake sites, all of which are in western and central Contra Costa and Alameda counties, face a gauntlet of threats. First among them is their isolation from one another and the genetic problems that poses. Not long ago, many of the populations were connected, allowing for the migration of individuals during fire and flood, and the exchange of genetic material needed to maintain a robust species over time. But reservoirs, housing projects, commercial developments, and highways have carved up their habitat, erecting barriers to genetic exchange.

According to the U.S. Fish and Wildlife Service (USFWS), fire suppression poses an even more immediate problem. Left to itself, ignited by lightning, the snake's habitat burns periodically every five to thirty years. These fast-moving, relatively cool fires clear out the brush and other flammable material which, if allowed to accumulate for greater lengths of time, fuel much more severe and destructive fires. Periodic burns also maintain the relatively open habitat whipsnakes need to make a living.

The "whip" in whipsnake aptly describes their speed and precision. There is a clear correlation between a reptile's speed and its body temperature. Research conducted by herpetologist Geoff Hammerson shows whipsnakes to have the highest mean active body temperature (33.4 degrees C) of any snake--at least any snake whose mean body temperature has been measured. Humans and other mammals are endotherms, meaning we generate our own heat. Reptiles, on the other hand, are ectotherms and rely on their environments for whatever heat they can muster. To maintain their high temperatures, and thus their speed, whipsnakes spend a lot of time basking in the sun. But lying out in the open would expose them to hawks and other predators. The relatively open scrub and chaparral gives them both protective cover and sufficient exposure to the sun.

Whipsnakes do their best hunting in the morning. Even before whipsnakes get to work, however, they often come completely or partially out of their burrows to sunbathe, soaking up the solar energy that will allow them to strike with lightning speed at the lizards, particularly fence lizards, that make up the bulk of their diet.

According to California State University at Hayward herpetologist Sam McGinnis, this specialization is the secret to both the whipsnake's success and predicament. Unlike most snakes -- even its closest relatives--the whipsnake does not rely primarily on chemical stimulation or vibration to find its prey. Instead, says McGinnis, whipsnakes are sight hunters. And nothing stimulates a whipsnake like a lizard. Generalists, like coast garter snakes and ourselves, are better at adapting when conditions shift. No frogs? Fine, we can get by on fish, or mice for that matter. But specialists like the Alameda whipsnake are less adjustable. If fire suppression leads to too much shade and sun-dependent lizards decline, or head for better territory, the whipsnake will follow. Except that, in the latter case, they can't, because they are surrounded by hostile, man-made environments.

Fire suppression in whipsnake habitat also exposes the snakes to the superhot conflagrations that eventually do come when smaller fires are suppressed. Again, this problem is intensified by the isolation of the snake's habitat. When fire comes, the snakes have no place suitable to flee to.

Throughout much of its range, there is now so much fuel that to just let habitat burn would be the undoing of the snake, and probably a lot of other wildlife, too. But some management agencies are hoping to employ controlled burn techniques to revitalize whipsnake habitat. The East Bay Regional Parks District, for instance, plans to begin a burning regimen this year that should create a patchwork of scrub and chaparral of different ages while reducing the threat of catastrophic burns. The whipsnake should appreciate that, says herpetologist and consultant Karen Swaim, who conducted telemetry research on whipsnakes in Tilden Regional Park. Swaim found that though whipsnakes primarily reside in rocky upland scrub and chaparral, they also slither into a variety of other habitats including adjoining grasslands and open woodlands, which they use for foraging and courtship.

Despite the fact that the parks may be the species' best hope for preservation, USFWS's final ruling cited concerns about the park district's ability to handle the pressures of nearby urban growth: more visitors (one park visitor recently saw an Alameda whipsnake that had been run over by a bicycle on one of the trails), more feral pets that prey on snakes, more homeowner insistence on fire suppression.

But the whipsnake has even bigger problems. Since 1970, according to a usfws study, approximately 65 developments in Alameda and Contra Costa counties either converted or encroached upon suitable Alameda whipsnake habitat. And there are a lot of development projects in remaining whipsnake habitat at various stages of planning or construction. In Alameda County, a project known as Hansen Ranch is now beginning to convert suitable whipsnake habitat into 474 homes. Then there are the Hayward 1900 and Baily Ranch projects; these two total 1,971 acres of Alameda whipsnake habitat on the Hayward-Pleasanton Ridge. To the east of the Las Trampas Regional Wilderness population of whipsnakes, the proposed Rossmoor Neighborhood Nine Project would also result in the direct loss of habitat.

This spring, the Gateway Project in Orinda--recently renamed Montenera -- plans to develop an 18-hole golf course and 225 homes on 978 acres of land adjoining known snake habitat. Though no snakes have been caught on the property itself, renowned University of California at Berkeley herpetologist Robert Stebbins says "a lot of the Montenera property would make excellent Alameda whipsnake habitat. I'd be very surprised if the snake weren't living there."

On the whole, the snake's new status as a federally listed species will strengthen its protection on these development sites. But listing is no guarantee. Even if no more habitat is lost, genetic isolation and fire suppression on "protected" habitat still present major obstacles. And if past is prologue, increasing human population and economic pressures will chip away at the snake's valuable real estate, and homes will be built on or adjoining whipsnake habitat in exchange for mitigations of dubious value.

Listing may also have a downside, according to USFWS. Some black-market reptile collectors specifically target endangered species. The new threatened designation, combined with relatively easy access, may put Alameda whipsnakes at risk. The usfws even declined to name critical habitat for the Alameda whipsnake, concluding that doing so would provide a road map for illicit collectors.

I spend so much time reading about environmental problems and the collapse of biological diversity that I forget how lucky we are. I slip into thinking of ours as California's post-wild period and long for the days when it was possible to see a grizzly snatching salmon from Lobos Creek in San Francisco's Presidio, clouds of migrating waterfowl darkening the Great Central Valley sky, or California condors plying the air currents up and down the coast. But should I have grandchildren, they will probably be amazed to learn that in 1998 I could drive a half-hour from downtown San Francisco and watch coho spawning; that I could walk through a Humboldt redwood forest and call out to northern spotted owls...and have my calls returned!; that only a few short miles from my urban North Oakland home, Alameda whipsnakes still hunted the hills. These may soon be California's good old wild days.

But then again, maybe the Endangered Species Act and other conservation legislation will prove that prediction too pessimistic. After all, 30 years ago it was very rare to see gray whales or brown pelicans on the California coast. Today they are gloriously common, thanks--lest we forget--to the Endangered Species Act.



Gordy Slack is an associate editor of California Wild and he is the editor of this website.

cover fall 1999

Spring 1998

Vol. 51:2