Three others have been found in recent days. One was at Crissy Field, one at the Berkeley Marina and another along the San Mateo Coast.
It isn't yet clear how the whales died. The first one was towed from Crissy Field to Angel Island for a necropsy.
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The video above is of a whale first spotted yesterday at Muir Beach.
You can see experts from the Marine Mammal Center conducting a necropsy on that whale this afternoon.
See more stories and videos about the environment here.