Just kitten! Officials say ‘mountain lion sighting’ was just cat

What was believed to be a mountain lion was seen around 20th Avenue and La Salle Drive in San Mateo on Sunday evening. What was believed to be a mountain lion was seen around 20th Avenue and La Salle Drive in San Mateo on Sunday evening. Photo: Courtesy San Mateo Police Dept. Photo: Courtesy San Mateo Police Dept. Image 1 of / 1 Caption Close Just kitten! Officials say ‘mountain lion sighting’ was just cat 1 / 1 Back to Gallery

Editor's note: Click here for the original story about what was believed to be a mountain lion sighting.

A suspected mountain lion sighting in San Mateo that prompted a police response and shelter-in-place order Sunday night turned out to be nothing more than a rather large domestic house cat, state wildlife officials said.

Experts with the California Department of Fish and Wildlife examined a concerned resident’s photo — which was released by the police department as a warning to the public — and measured the cat’s length against a sign just above the feline, said Steve Gonzalez, a spokesman for the agency.

What they concluded: there’s no way that was a mountain lion.

“It wasn’t a mountain lion, but I think it’s good to be cautious,” Gonzalez said.

Asked the level of certainty of the mysterious cat being domestic, he said, “100 percent.”

The animal was spotted about 8 p.m. near 20th Avenue and Le Salle Drive, a neighborhood near Junipero Serra High School and Peninsula Golf and Country Club.

Officers from the San Mateo Police Department set up a perimeter and tried to pin the animal down while sending an emergency notification to residents asking them to shelter in place.

After an hour-long hunt that failed to locate the alleged mountain lion, police pulled out of the neighborhood.

Authorities told the community to stay away from the animal and immediately call police if it was spotted again. Residents were also advised not to run but face the animal, make noise, try to appear big and throw rocks or other objects at the cat to scare it off.

But it was all for naught.

“Typically cats are kind of smaller,” Gonzalez said. “The time of day made it look a little more ominous.”

Kimberly Veklerov is a San Francisco Chronicle staff writer. Email: kveklerov@sfchronicle.com Twitter: @kveklerov