PLEASANTON -- The Bay Area's version of Nessie has been spotted again.
This time, the mysterious and elusive large black cat that has reportedly stalked East Bay hills was seen in Pleasanton.
Jo Gunderson, a recent San Francisco transplant, was with her 1-year-old daughter Thursday at Alviso Adobe Community Park when she saw what she said is a black panther.
"It is so weird to describe," Gunderson said. "Even though I hadn't heard the myth, I just knew there were no such things as black cats in North America. But there is no mistake about that shaped head and how massive it was. It was not a house cat."
Although wildlife experts are skeptical, there have been other sightings of a large black cat in the area. In July 2009, a couple reported seeing a huge, dark cat on a hillside in the same area.
Lynn and Kathleen Reed were headed east on Interstate 580 when they saw the cat on the southwest side of the freeway near Foothill Road. Lynn Reed said he saw a similar cat 13 years before at his Castro Valley ranch.
Gunderson said the cat she saw was about 5 feet long, with an equally long tail. She saw it in an open field near the park's farmhouse and first thought the head was a rock. But when she made a sound and saw it move, she knew it was something much larger.
"It was like seeing a yeti," she said. "It was just a shock. You get stuck in a trance, and I was telling myself, 'Is that really a black, massive cat in front
Gunderson said she was 80 feet from the animal and knows what she saw. It wasn't a house cat or a cougar, she said. She has had house cats all her life and has seen pumas in the Santa Cruz Mountains.
"It was just surreal," said Gunderson, who swooped up her daughter and high-tailed it back to her car.
Wildlife specialists for the East Bay Regional Park District and the state Department of Fish and Game say it's unlikely a large black cat roams the Bay Area, but not impossible.
"Jaguars had been extricated from the country for quite a while," said Steven Bobzien, a wildlife ecologist for the park district. "There were reports of jaguars being seen (in Arizona) but there was no solid physical evidence. It was similar to what we are going through with these black cats here. (Gunderson) may have seen one, but without evidence, people are going to be skeptical.
"Overwhelming evidence suggests black mountain lions do not exist. Although I would not completely dismiss the possibility, it is highly unlikely."
Experts said the majority of puma sightings are erroneous, with other species including bobcats, cats, coyotes, dogs, and foxes mistaken for the large cats.
Bobzien said he first heard reports of large black cats 30 years ago in Marin.
In the 1970s, Contra Costa County ranchers reported seeing a big black cat in the San Ramon area. It was found to be an escaped pet black leopard.
Bobzien said the first proof of jaguars, which can be black, reappearing in the United States was in 1996 with a photo taken in Arizona. Since then, others have been spotted in Arizona and New Mexico.
Fish and Game officials say they hear of thousands of puma sightings a year and sometimes hear of a black panther, which are more likely dark mountain lions.
"From an ecologist's perspective, if someone was to produce evidence it would be remarkable," Bobzien said. "I would be smiling. Nature never seems to surprise me."
Staff writers Denis Cuff and Gary Bogue contributed to this report.