Features

If our city ever adopted an official civic rodent, there would be only one possible choice. No, not who you’re thinking about; I’m referring to the Berkeley kangaroo rat, Dipodomys heermanni berkeleyensis. 

As far as I know, this is the only creature that has Berkeley embedded in its scientific name. It was discovered here about a month before the end of World War I, on a grassy hilltop at the head of Dwight Way, and christened in 1919 by Joseph Grinnell, for decades the doyen of bird and mammal studies at the university. 

We don’t know all that much about the rat’s natural history. Grinnell considered it a new species, but later taxonomists demoted it to the status of a subspecies of the Heermann’s kangaroo rat, which has a wide distribution in central California, from the Sierra to the coast. 

Subspecies is one of those slippery categories that a lot of biologists would like to junk altogether. A subspecies is a population that appears physically distinct from other populations but can still, given the opportunity, interbreed with them. It may, like a full species, be entitled to the protection of the Endangered Species Act. Many of the poster creatures of endangerment, like the infamous northern spotted owl, are subspecies. 

Heermann, incidentally, was Adolphus L. Heermann, a colorful 19th-century frontier physician-naturalist who made it to California at the peak of the Gold Rush, but was more interested in wildlife than wealth. In addition to the kangaroo rat, he’s the namesake of the Heermann’s gull that follows the pelicans up from the Sea of Cortez in summer. 

Kangaroo rats in general are engaging little creatures, with powerful hindlegs for hopping and a long tail ending in a tufted tip. “Rat” is a misnomer; they’re more closely related to squirrels and gophers than to conventional rats. Most of the 22 species are adapted to arid regions and never need to drink, obtaining all the water they need from the plants they eat. The Heermann’s species, though, living north of the deserts, requires free water. Typically, a Heermann’s kangaroo rat spends most of its life underground, either digging its own elaborate tunnel complex or moving into an old ground squirrel burrow. It surfaces after dark for brief foraging bouts, harvesting seeds and green vegetation. 

Not one of your more conspicuous animals, in short. And I have to admit that I had never even heard of the Berkeley kangaroo rat until this spring, when the US Fish and Wildlife Service issued its draft recovery plan for the chaparral and scrub ecosystems of the East Bay. Rather than focusing on a single endangered species, the plan covers a natural community that’s home to several at-risk plants and animals. The plan’s marquee species is the Alameda whipsnake, a handsome black-and-yellow serpent that’s confined to a few disjunct patches of habitat. But it also encompasses four plants—the pallid manzanita, Contra Costa manzanita, Mount Diablo bird’s-beak, and Mount Diablo buckwheat—and the rat. 

All well and good, except that the rodent appears to be extinct. None have been reliably reported since 1940, when a specimen was collected near the Calaveras Reservoir. (That was also the last year anyone saw the Mount Diablo buckwheat). A recovery plan for the Berkeley kangaroo rat seems, on the face of it, about as useful as a recovery plan for the California grizzly. 

But I wouldn’t be too quick to judge this as another instance of federal foolishness. It’s much easier to misplace a kangaroo rat than a bear. A small, subterranean, nocturnal species can easily go unnoticed. Other secretive mammals have turned up after long absences: the black-footed ferret, for one, which had been given up for lost when a farm dog in Meteetse, Wyo., brought home one of a colony of survivors. 

And there have been intriguing rumors of rats in the last few decades: a report of an apparent kangaroo rat trapped near Mount Diablo in the 1980s, another killed by a Blackhawk resident’s cat. Biologist Gary Beeman, who has been searching for the creature for more than 10 years, believes there may still be a few out there. Beeman has wanted posters up in strategic places; I recently saw one in the visitors’ center at Mount Diablo State Park. 

Being still officially extinct, the Berkeley kangaroo rat is not on the endangered species list and doesn’t merit critical habitat designation. But it makes sense for the federal guardians of the whipsnake and the manzanitas to keep an eye out for the rat, just in case. Or for other evidence of its existence, like suspicious droppings. Someone at the Smithsonian Institution has developed a technique for analyzing mammal scat for genetic markers that, according to the authors of the recovery plan, could be applied to the kangaroo rat. 

I wouldn’t count on the rats still being where Grinnell first found them: there’s been too much development in the Berkeley Hills, too many prowling cats. If you do happen to encounter a long-tailed creature hopping through the chaparral, though, Gary Beeman would like to know about it. You can reach him at (925)284-2602.