3. Fauna

There are no indigenous land mammals on Cocos Island. The only five that now live on the island are rats, pigs, cats, goats and white tail deer, which were introduced in the recent past by humans, either intentionally or accidentally. The wild pigs and the rats are a real problem because of their negative impact on the environment and on biological diversity. Some kind of control or management program is needed.

There is a resident population of bottlenose dolphins living in the waters surrounding the island. Occasionally other sea mammals such as the false killer whale, the cuvier-beaked whale, the hunchback whale and the sperm whale have been observed. Sea lions from the Galapagos Archipelago have also been identified. Their presence is related to the warming of the waters that is produced by El Niño.

There are 100 species of birds on the island, 13 of which are resident, meaning that they reproduce on the island, and the remainder are either regular or occasional visitors. Of the resident species, five are land birds and three of those are endemic to the island: the flycatcher, the cuckoo and a finch. In addition, the warbler is endemic to both Cocos Island and the Galapagos. The finch found on Cocos Island, along with the 13 varieties of finches on the Galapagos Islands, form part of the so-called Darwin Finches, which helped Charles Darwin form his premises about the evolution of the species.

The remainder of the resident birds are sea birds, the most outstanding of which is the white or fairy tern, or Holy Spirit dove. The bird is present in the western Pacific, but only nests on Cocos Island.

The only two land reptiles are a small lizard and a gecko salamander; both species are endemic to the island. Marine turtles have been observed in the waters surrounding the island: the olive gridley, the eastern Pacific green turtle, and the hawksbill. However, there are no indications that they nest on the island. There are also records of the Pacific Ocean water snake. There are five species of fresh water fish on the island, three of which are endemic: the clingfish, goby and sleeper.

Currently, the integrity of the exceptional and fragile marine and land biodiversity of Cocos Island is being threatened. Directly or indirectly, the presence of human beings has been and continues to be the origin of this threat.

The first threat is the presence of aloctonous (non-autoctonous) species. That is to say, plants and animals that were accidentally introduced by human beings. Among those animals that were introduced and that have established themselves on the island are pigs, goats, cats, rats and the white tail deer.

In their search for food, the pigs root up the ground, which is washed away by the heavy rainfall, which in turn results in erosion. These materials are carried towards the ocean, which results in dirty water and sedimentation on the coral ecosystems that surround the island; this can lead to degradation and death. Rats eat all kinds of organic matter, and on Cocos Island they eat different species of flora and fauna, endangering the incredible diversity of the island, especially that of the endemic species. The impact of the cats, goats and deer has not been studied, but it is assumed that their impact is less than that of the other two species.

Illegal fishing within the protected marine area of Cocos Island is seriously compromising the fauna and the marine ecosystems, as well as the island's function as an area for reproduction and maintenance of marine productivity in the region. Illegal fishing takes place in different ways: sport fishing and hunting; extraction of lobsters and cabrilla, which are endemic to the island; and above all, unselective and destructive commercial fishing techniques, such as the use of fishing line with multiple hooks or long lines used to catch sharks.

The growth of tourism on the island, especially in the ocean area, is affecting some of the outstanding natural characteristics of the scenery, ecosystems and marine organisms. The physical contact of the tourist-divers with marine organisms, the destruction of the bottom of the sea by incorrect anchoring, the extraction of biological materials, the production of liquid and solid waste, which are not correctly managed, are some of the threats that tourism produces. Appropriate regulations are lacking for the use of the area as a tourist site.

Lastly, the lack of economic, human and technical-scientific resources make it impossible to adequately manage the biodiversity of the island in an appropriate manner.