Los Farallones

Dispatches from Point Blue’s field station on the Farallon Islands National Wildlife Refuge

Did Somebody Say Sperm Whale?

Each day on the Farallones, you truly never know what you are going to wake up to find. On the morning of February 2nd, the Farallon crew almost didn’t believe our eyes when we arrived at the elephant seal colony to find the body of an immature sperm whale washed up on Mirounga Beach. This calf was approximately 20 feet long and took up the entire entrance to the small beach where six of the elephant seal cows currently reside. The cause of death is unknown and there appeared to be a postmortem shark bite taken out of the animals back.

Sperm whales are one of the deepest diving cetaceans in the ocean, alongside beaked whales, with diving depths recorded from 400-2000 meters. Part of the family Odonteceti, or “toothed whale,” they forage for squid and other deep sea organisms at these depths. They are occasionally seen along the California coast although most of their time is spent in deeper waters. In the last 5 years there have been just a handful of publicly reported sightings between Cordell Bank and Monterey Bay, and several were of whale carcasses washing up on beaches. The last reported beaching was in 2015 in Pacifica, near San Francisco.

Why are they called sperm whales you may be wondering? If you notice the large bulge on their head, it is filled with a white fluid called spermaceti that is used in echolocation, something initially mistaken by humans as sperm. Sperm whales are also known to have the largest sheer brain size of any animal species on Earth.

As the tide reached its high for the day, the water washed the whale out of Mirounga Beach and into another rocky area of intertidal. Just before the sun set, the whale began drifting off shore and back out into the open expanse of the ocean.



“Fifty-foot sperm whale washes up on shore south of San Francisco” Associated Press in Pacifica, California. 15 Apr 2015.Peter L. Tyack, Mark Johnson, Natacha Aguilar Soto, Albert Sturlese, Peter T. Madsen.

“Extreme diving of beaked whales”  Journal of Experimental Biology 2006 209: 4238-4253.William A. Watkins, Mary Ann Daher, Kurt M. Fristrup, Terrance J. Howald, Giuseppe Notarbartolo Di Sciara.

“Sperm whales tagged with transponders and tracked underwater by sonar” Marine Mammal Science, Vol 9 Issue 1. January 1993.Whitehead, Hal.

“Sperm Whales: Social Evolution in the Ocean” University of Chicago Press, 2003.

“Sperm Whale (Physeter Macrocephalus).” INaturalist,