A recent study conducted by the Zoological Society of London (ZSL) on endangered Galapagos sea lions (Zalophus wollebaeki) has revealed that the animals are more susceptible to starvation as a result of their exposure to humans. Over a span of more than 18 months, conservationists tagged and monitored the behavior and physiology of two groups of 60 Galapagos sea lions, one in San Cristobal, which is inhabited by humans, and one in Santa Fe, where there are no humans, dogs, cats, mice, or rats.