The group Heal the Bay says a 2-foot-long yellow-bellied sea snake was found on the sand Friday at Silver Strand Beach in Oxnard in Ventura County. But it died a short time later.
Local resident Anna Iker snapped a photo of the snake while watching her kids play in the water, CBS Los Angeles reported. It's one of two seen in the area this week.
"I was really shocked because we don't even see land snakes around our neighborhood," Iker said.
The black-and-yellow snake, which is common south of the border, may have been drawn north by warmer ocean temperatures attributed to the El Nino condition.
Experts say it's highly venomous, but it is unlikely to attack unless grabbed or otherwise molested.
The Los Angeles Times says the body was sent to the Los Angeles County Natural History Museum, where it was examined Saturday and samples were taken for DNA analysis.