The re-beavering of the Bay Area
Plump, smelly and paddle-tailed, this important rodent is making a comeback in San Francisco Bay creeks
In a deep muddy creek near Silicon Valley’s busiest freeway, a large furry head pokes up. And then quickly submerges.
The brief sighting, along with a growing collection of video footage, confirms something remarkable: After being hunted to extinction in the 1800s, the North American beaver is returning to the creeks of the San Francisco Bay Area.
Ecosystem explorers, beavers were re-introduced to Lexington Reservoir in Los Gatos about four decades ago, and made homes in upper Los Gatos Creek. Since then, they’ve expanded their range north along the edge of the Bay to the Guadalupe River, Coyote Creek, San Tomas Aquino Creek in the wetlands by Sunnyvale’s Water Pollution Control Plant — and, now, Palo Alto’s Matadero Creek.
“There’s a resilience that’s built into their DNA to find a location, set up shop, find a mate and go to work on increasing the population,” said naturalist Bill Leikam. This week, his trail cameras captured proof that a pair of beavers — male and female — enjoy evening strolls together along the creek, just two miles from the global headquarters of Intuit and Google.
Plump, smelly and paddletailed, beavers shaped the California landscape for thousands of years. Their dams built ponds, slowed runoff, cooled stream flow and re-charged aquifers, creating pockets of biodiversity in a hot and dry landscape.
They were eradicated by the 1840s, when fur trappers swept through the west in search of pelts for men’s beaver top hats, which were warm, waterproof and an essential part of a sophisticated wardrobe.
“They were little $20 bills swimming around,” said Heidi Perryman of Martinez, who founded the beaver advocacy group, Worth a Dam.
But conventional wisdom held that the rodents had never lived here in the Bay Area. In historic range maps published in 1937 by preeminent zoologist Joseph Grinnell, the first director of the Berkeley’s Museum of Zoology, they were nowhere to be found.
More recent research suggests that Grinnell got it wrong — and the Bay Area has always been a soggy beaver paradise.
While visiting the Smithsonian Museum in Washington D.C., Palo Alto-based physician and amateur ecologist Dr. Rick Lanman discovered a beaver skull from Saratoga Creek collected in 1855. A beaver tooth and some bones, dated back to A.D. 300500, were found at Emeryville Shellmound, a sacred burial site of the Ohlone people located on historic Temescal Creek.
Now beavers are back, in a long-overdue homecoming.
They’re unlikely celebrities: they’re nearly blind, eat their poop, and have anal glands that emit musky yellow-tinged oil to mark their territory. Reclusive, they’re rarely seen in the wild because they tend to work in the dark, avoiding people.
But they’re increasingly cherished for their role as civil engineers, creating complexity in a landscape by building ponds that serve as safe habitats for fish, otters, herons and other wildlife. In celebration last April, supporters gathered for the first-ever California Beaver Summit. Every June, the town of Martinez hosts an annual Beaver Festival.
The Palo Alto beaver was first spotted one morning by a nature-lover who was meditating on the creek bank. Startled out of his reverie by the three-foot swimmer, he told Leikam about the sighting. Leikam set up a network of camouflaged trail cameras to confirm the animal’s presence.
Now, twice a day — at dawn and dusk — Leikam, 82, weaves through dense thickets of willow and fennel along the banks of Matadero Creek on a two-milelong route to inspect his 14 cameras, memory cards and batteries.
Discarded plastic bottles, aerosol cans and other trash litter the