The motivation to migrate

When visiting the Sea Lion Center, one may become intrigued by California Sea Lions' migratory behaviors and ask questions such as:

Why do animals migrate?

Males only?

And why so far?

With California Sea Lion migration, it’s all about food and breeding. There’s better food up north, and the ladies are down south. The females don’t migrate because simply stated, the costs outweigh the benefits.

If it were beneficial to swim north for hundreds of miles or maybe thousands while pregnant, then we would see that happening. But we don’t. That said, and because there’s always an exception to the rule, females have been seen migrating north in years of difficulty, such as El Niño’s. However, that’s when the food is so low that they are forced to explore outside their normal hunting grounds. Pregnant females have been known to miscarry if the pregnancy cannot be sustained.

Ultimately, migration comes down to energetics:
  • If benefits > costs = migrate (males)
  • If benefits < costs = don't migrate (females, for the most part)
The average life span of a California Sea Lion is 20–25 years.
Sea Lions are considered “opportunistic feeders,” eating available prey rather than one species.