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Galapagos sea Lions and fur seals, adapted to a variable world

Abstract:

Galapagos otariids (Galapagos sea lions Zalophus wollebaeki, and Galapagos fur seal Arctocephalus galapagoensis) have developed a number of behavioral adaptations to living in a tropical ecosystem exemplified by high environmental variability and subsequent oceanographic disturbances that lead to unpredictable marine productivity. Both species have been subject to selection pressures to reduce overall body size and energy requirements compared to otariids living in more predictably productive systems. The environmental stochasticity also appears to have modified both reproductive and foraging behavior. Galapagos otariids respond to limited food supplies with prolonged lactation, thus enhancing the chances of pup survival, and have developed trophic specialization with a high level of flexibility that reduces interspecific competition, combined with prey-switching during El Niño events. Galapagos fur …