Marine iguanas of the Galapagos Islands face novel threats from climate change and introduced species that affect individual welfare and population viability.
During El Nino events, marine iguanas face slow starvation as their algae food supply disappears. Iguanas that survive lose body mass dramatically — some appear to shrink as they reabsorb bone for energy. The stress of starvation and thermoregulatory challenges causes significant suffering in surviving populations. Introduced predators cause fear-related stress and direct predation mortality in what was an island ecosystem with few natural predators.