I am in the process of reading “New Directions in Ecological Physiology” and I came across something I had to write a post about. It falls in the catagory of “My god, that is so obvious, why didn’t I think of it?”
The northern fur seal (Callorhinus ursinus) is adapted for heat retention while in the water. However, this causes problems when the seal is on land, for example some seals have died of heat shock in 10 c temps.
Zalophus californiansus (California sea lion) also faces this problem. Interestingly enough the California sea lion also occurs in the Galapagoes. So the we can compare how it solves the heat problem with A. galapagoensis. A. galapagoensis
Both the California sea lion and the Galapagos fur seal are highly polygamous. Males compete for large territories and try to acquire large harems of female seals. So, the question is how do you compete and avoid heat stress? The Galapagos fur seal competes for territory and mates on land, however, its land habitat of choice are wave cut caves and talus slopes containg large boulders (to hide in the shade of). The California sea lion competes for territory in the ocean and comes ashore primarily at night for mating purposes.
Two points need to be made. The first is that, as the above example shows, behavior can be used to expand niches. The second is that adaptations have unintended consequences. Adaptation to cold oceans can lead to problems when it is time to come ashore. The interaction between being adapted to a cold environment and needing to inhabit a warm environment (for however short a time) has yielded a complex answer.