Marine iguanas of the Galapagos are uniquely vulnerable to climate events, with El Nino years causing mass starvation that represents one of the most dramatic welfare events in natural history.
Marine iguana mass starvation events represent natural suffering at extraordinary scale — tens of thousands of animals dying slowly from starvation across weeks during El Nino years. These events are not human-caused but their frequency and intensity are increasing with anthropogenic climate change. The welfare of individual marine iguanas during these events — lethargy, weight loss, failure of reproductive function, eventual death — is acute and widespread. Conservation actions that protect non-El-Nino year populations and support ecosystem resilience are the most practical welfare interventions available, even if the suffering of individual animals during events cannot be directly alleviated.