On today’s third installment of Species Tuesday, we highlight the charismatic California sea lion. Now, let’s begin by clearing up the differences between sea lions and their more soulful cousins, seals. While they’re both pinnipeds, there are quite a number of physical differences between the two marine mammals. Sea lions have large flippers that they use to walk around on land, are typically brown in color, and have large, visible earflaps. Seals, on the other hand, wriggle on their bellies while on land due to their small flippers. They’re also usually gray or silver in color and lack visible earflaps.
California sea lions are sexually dimorphic, with males measuring about eight feet, 770 pounds and females coming in at a smaller six feet, 220 pounds. After about ten years, male sea lions exhibit a protruding crest on top of their heads, reflecting the animal’s strong jaw muscles. In an attempt to branch out from society’s preconceived expectations about how they should look, male California sea lions rarely grow a distinct mane (you be you, CSL). Females and juveniles usually are brown in coloration, though after molting their fur appears a more light gray.
These west coast mammals stake their turf from southern Alaska all the way south to Mexico. Individuals gather on sandy or rocky Pacific beaches during the breeding season, when the weather is warmer. During colder spells, California sea lions can be found feeding in nearshore waters. Their major prey items include clams, squid, and many different types of fish. In turn, transient killer whale pods and large sharks prey upon California sea lions.
The California sea lion, though a single species, is comprised of five genetically-distinct populations:
- The U.S. Temperate stock
- The Baja California (or Pacific Tropical) stock
- The Southern Gulf of California stock
- The Central Gulf of California stock
- The Northern Gulf of California stock
As we discussed in an earlier post about Pacific tuna, it’s critical to conservation efforts that representatives of each genetically-distinct population within a species be protected to ensure adequate genetic diversity within the group. Further, as our climate continues to change and marine animals shift their distribution accordingly, we must increase our monitoring efforts of the California sea lion and its respective prey items to understand how this species will adapt to future environmental conditions.
Enjoy the Podcast!