This group of California sea lions (Zalophus californianus) was hauled out on a dock in Westport, Washington. The scene reminded me of Pier 39 in San Francisco — although on a much smaller scale. California sea lions are a protected species and, by law, all marine mammals should be viewed from a distance of 100 yards wherever possible. These images were shot with my 70-300mm lens, with a reach of 600mm (35mm equivalent), so the proximity is an illusion of the lens.
I always marvel at how sea lions get any rest at all, given the squabbles that arise each time a new sea lion leaps onto the dock and crawls over the mass of sleeping animals. This description covers the behavior well (from The Natural History and Behavior of the California Sea Lion – Peterson, Bartholomew 1967):
Non-breeding individuals are always highly gregarious while on land. They often pack themselves so closely together that arriving or departing animals must crawl over the bodies of the others. These congested groups form even though large sections of adjacent beach remain unoccupied. The animals are strongly thigmotactic and while sleeping tend to keep their bodies pressed against each other. Even non-territorial bulls lie close together in this way, especially in winter. Sometimes small individuals may lie on top of larger ones, but this is not tolerated for extended periods of time. They also rest on the backs of elephant seals or on piles of kelp, seemingly preferring these soft resting places to rocks.
For more intricate details and scientific papers on sea lions and other marine mammals, check out the Marine Mammal Center’s online library. If you live in or are visiting the San Francisco Bay Area and are interested in marine mammal rehabilitation, you can tour the state-of-the-art facility in the Marin Headlands for free. It’s an incredible sanctuary for the 600 or so marine mammals rescued each year by the Center.
Sea Lion Factoids
- Sea lions have an automatic dive response, bradycardia, that slows the heart rate and conserves oxygen. This study monitored variations in the sea lions’ physiological responses.
- Male Steller sea lions, larger than California sea lions, can reach 11 feet in length.
- Sea lions are polygamous, and aggressively defend their large harems.
- The most significant human threat to sea lions is entanglement in nets and fishing gear. They are also found illegally shot and otherwise harmed. Abnagale was one sea lion fortunately rescued from such an entanglement by the Marine Mammal Center.
- Sea lions are protected under the Marine Mammal Protection Act. It’s important to know the law if you’re in areas where interaction with marine mammals is common. As a general rule of thumb, stay 100 yards away.
- You’ll find California sea lions from Vancouver Island, B.C. in the north, to Baja in the south.
- Wherever large numbers of sea lions congregate, you’ll see rafting behavior — large clutches of sea lions floating as a mass, often with flippers held up out of the water.
One of several harbor seals (Phoca vitulina) milling about in the same area.
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