Also called simply Seymour, North Seymour’s topography is flat and strewn with boulders since this island was formed by a seafloor uplift instead of having a volcanic origin as most of the Galapagos Archipelago.
The island is mainly populated by Magnificent Frigatebirds, which nest nearly year round, and blue-footed boobies that use the inland of the island as a nesting site.
Marine iguanas and sea lions are usually present on the shores and cliffs, a space shared by swallow-tailed gulls and Sally Lightfoot crabs.
One of the main attraction of this visit is the observation of an unusual colony of marine iguanas who adapted to eating the plant Batis maritima instead of the algae that marine iguanas normally eat. It's also possible to see land iguanas here even though they are not endemic to North Seymour; these iguanas were introduced from Baltra Island as part of an experiment in the 1930s. Although introducing an invasive species to an ecosystem is no longer accepted in science, this introduction was fortunate because the land iguanas in Baltra became extinct in the 1940s, and nowadays Baltra is being repopulated with the specimens found in North Seymour.