California sea lions (Zalophus californianus) choose their habitats based on having optimal thermoregulation (maintaining their body temperature). Some of their preferred habitat characteristics include large, flat rocks, lighter surfaces, and protected coastlines from wave action. These features allow California sea lions to easily perform thermoregulation behaviors such as basking on large flat surfaces (like the famous Pier 49 dock in San Francisco, CA) or retreating underneath large rocks for shade, as well as easy entry and exit points to cool off in the water without exerting too much energy.
[Photo by Nick Chudeau and caption by Karli Chudeau]
Gonzalez-Suarez, M. & Gerber, L.R. (2008). Habitat preferences of California sea lions: Implications for conservation. Journal of Mammology, 89(6), 1521-1528.