Which Galapagos animals did Charles Darwin study during his visit?

During his 1835 visit to the Galapagos Islands, Charles Darwin encountered several unique species that later contributed to his development of the theory of natural selection.

The animals he observed and studied included:

• Giant tortoises: Darwin noted the presence of these large creatures, which were well-known to local inhabitants who believed each island hosted distinct races of the animals.1
• Marine iguanas: He observed these swimming lizards, which were endemic to the islands and fed on seaweed along the coastal rocks.21
• Birds: Darwin collected various bird specimens, including mockingbirds, which he noted differed across four of the islands. He also encountered what he initially categorized as finches, wrens, and oriole-relatives, though he famously failed to label these specimens by their specific island of origin at the time.13

While Darwin and his crew kept some small tortoises as pets during their voyage, his scientific observations of the archipelago's fauna were instrumental in his later analysis of how isolated populations adapt to their environments.13