50-foot sperm whale carcass washes ashore at Pacifica beach

Video: Beached Sperm Whale In Pacifica

The decomposing carcass of a nearly 50-foot sperm whale washed up on a beach in Pacifica on Tuesday, according to officials from the Marine Mammal Center in Sausalito.

It was unclear exactly when the massive whale appeared on the beach, how it died or what would be done with it, but researchers from the center, as well as from the California Academy of Sciences, would perform a necropsy on Wednesday to try to determine a cause of death.

In January, a rare pygmy sperm whale died after beaching itself in Point Reyes. Investigators in that case said the whale had likely gotten sick and was too weak to swim.

Kale Williams is a San Francisco Chronicle staff writer. E-mail: kwilliams@sfchronicle.com Twitter: @sfkale