Galapagos Wildlife

The native flora of the Galapagos totals about 500 species, of which some 175 are endemic. There are a further 550 or so introduced species. As with the animal life, evolution has expressed itself by producing a number of adaptive radiations among Galapagos plants. Scalesia, a member of the daisy family, has 21 different subspecies, ranging from small shrubs to trees, while the prickly pear Opuntia had developed 14 subspecies.

Because of the archipelago’s isolation, the number of invertebrate species is relatively small compared to continental regions of similar size. There are some 2,200 insects and other invertebrates in Galapagos, of which about 53% are endemic. Nevertheless, there are quite a few examples of species ‘swarms’, or a diversity of species that have evolved from a single ancestor. For example there are 65 species of land snails from one ancestor – although unfortunately many of these are now extinct.

The only native land mammals are two bats and four species of rice rats. The latter are endemic and of great scientific interest. Several domesticated animals have been introduced (cats, dogs, pigs, and even donkeys and cattle), and some pest species such as rats and mice have made the islands their home. These can cause problems for the native species, but conservationists are having some success in campaigns to remove them.

While mammals dominate the land fauna in most of the world, in Galapagos it is the reptiles that hold sway. Best known are the giant tortoises that once numbered around 250,000 but are now down to about 15,000. Of the eleven subspecies still found on the islands, there is one represented by a single surviving male, Lonesome George.

There are two species of land iguana, and one species of marine iguana on the islands. The latter has seven subspecies which vary greatly in size and colour. There are also lava lizards, geckos and several species of snakes which are unique to the islands.

The marine fauna and flora of the Galapagos are in their way just as unusual and worthy of study as their terrestrial counterparts. Indeed, the marine realm has been described as the most scientifically interesting area of its size in the world. The archipelago sits at the crossroads of three major oceanic current systems coming from the north, west and south. It thus has a unique combination of tropical species such as corals, hammerhead sharks, and manta rays; temperate species, such as kelps and sea lions; and species more typical of cold regions such as a fur seal, an albatross, and a penguin. Overall, the level of endemism is around 20% – an extremely high average figure.