A male coyote confounded wildlife biologists earlier this year by swimming roughly 2 miles across San Francisco Bay from Angel Island to Alcatraz Island — a route twice as long as experts had initially assumed, the National Park Service announced Monday.
“Our working assumption was that the coyote made the swim from San Francisco because it is a significantly shorter distance,” Bill Merkle, a National Park Service wildlife ecologist, said in a news release. “We couldn’t help being impressed by his accomplishment in making it to Alcatraz.”
The coyote was first recorded in video footage paddling through the chilly bay in early January and was photographed on Jan. 24 by Rebecca Husson, who spotted the animal during a morning tour of Alcatraz while in town for a cousin’s wedding.
“He looked like a drowned rat when he ended up on the island, and when we saw him he looked healthy and so beautiful,” Husson told The Associated Press. “He looked like he had been eating well.”
Biologists collected coyote tracks and scat from Alcatraz and sent the material to the University of California, Davis, for DNA analysis. The results confirmed the animal belonged to the coyote population on Angel Island, surprising officials who had been operating under the San Francisco-landfall hypothesis.
Camilla Fox, founder and executive director of the nonprofit Project Coyote, said the animal likely left Angel Island in search of a mate or new territory. She noted that coyotes, like wolves, are capable swimmers, though long-distance ocean crossings are rarely documented.
“We have never, ever heard such a story of a coyote making such a long journey in a pretty challenging ocean current,” Fox said.
The Park Service had prepared to capture and relocate the coyote because Alcatraz serves as an important seabird nesting habitat. But the animal has not been seen again, and officials say there is no evidence it remains on the island.
Alcatraz Island, a former maximum-security federal prison notorious for its cold, swift currents and escape-proof reputation, is now part of the Golden Gate National Recreation Area. Its nearest landfall is San Francisco, just over 1 mile away. Angel Island, a state park that once housed an immigration detention center, was colonized by coyotes years ago — a feat that required the animals to cross open water in the first place.
“It wasn’t easy for coyotes to colonize Angel Island, but they persevered,” Fox said.
Fox urged visitors to Angel Island and other open spaces to be mindful of coyote dens, noting that the current season is pup season.