That's why the Galapagos National Park Service pursued a dogged campaign to eradicate goats from several of the islands, including Pinta, Santiago and northern Isabela.
The Galapagos goat population fed on native vegetation and competed with the giant tortoises for food, literally eating some species into extinction. A handful of goats were brought to Santiago Island in the 1800s and were once estimated to number close to 100,000. Non-native species introduced to the islands - whether today when a plane touches down or hundreds of years ago when explorers landed - have compete with endemic wildlife for food. An unsustainable rise in legal and illegal commercial fishing of sea cucumbers, shark fins and lobsters threatens marine ecosystems. Additionally, overfishing and the introduction of non-native species are causing environmental problems on the islands. The human impact - both the growing rate of permanent residency and tourism - poses a threat to the islands' ecosystems and availability of resources and services. Darwin's finches began as a single species of finch when they arrived on the islands, but through mutation and natural selection, they evolved into different species with different beak shapes - giving each an advantage in the specific island habitats. These finches are an example of what's called adaptive radiation, the process of rapid speciation of a single species. Competing with the giant tortoises for most famous species on the islands are the 13 species of finches, known as Darwin's finches because they provided evidence for his theory of evolution by natural selection. There are several reptile species including land and marine iguanas (marine iguanas are the only lizard known to swim in the ocean), lava lizards, geckos and snakes, 1,600 species of insects and 400 species of fish. Fourteen distinct subspecies of giant tortoise live on the islands, for example, as well as the only tropical-dwelling penguins. The Galapagos Islands are important because of these endemic species - there are roughly 9,000 species living on the islands and in surrounding waters. The blue footed booby booby is one example: These birds have stopped nest building in their isolated habitat and lay eggs directly on the ground. Many are fearless from living without predators.
While explorers and sailors left behind some animal inhabitants, such as goats and pigs, much of the wildlife on the islands are endemic species, some exclusive to certain islands in the archipelago. Exclusive species of cotton, guava, passion flower, pepper and tomatoes all grow here. There are more than 500 plant species found on the Galapagos, about one-third of which are endemic, meaning they're native to the islands and found nowhere else in the world. Solid bare lava forms cliffs and coastlines. They are spread out over 36,000 square miles (about 93,200 square kilometers) in the Pacific Ocean, a little more than 600 miles (1,000 kilometers) off the west coast of Ecuador. In addition to the 13 large islands, there are many more small islands and islets, all together about 3,000 square miles (8,000 square kilometers) of land total. The Galapagos Islands are a remote tropical archipelago made up primarily of 13 big islands: the Baltra, Espanola, Fernandina, Floreana, Genovesa, Isabela, Marchena, Pinta, Pinzon, San Cristobal, Santa Cruz, Santa Fe and Santiago. While they didn't stick around, their nickname for the islands did: Galapagos, which means "tortoise" in Spanish. De Berlanga and his men reported finding islands with tame wildlife, giant tortoise in abundance and little-to-no freshwater. That distinction goes to Tomas de Berlanga, the Bishop of Panama, and his crew when their ship drifted there in calm ocean currents in 1535, 300 years before Darwin arrived on the HMS Beagle. Although Darwin made them famous, he can't take credit for their discovery. Many of us recognize the Galapagos Islands as the place that inspired Charles Darwin's theory of evolution.
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