Rats are considered an invasive species in Galapagos and today they represent one of the greatest threats to the ecosystem of the islands. These rodents were brought to the islands over the course of several centuries aboard the ships of pirates, whalers and buccaneers who used the Galapagos as a stopping point during their voyages. Their ability to reproduce very quickly and to survive in hostile conditions has turned them into a pest on several islands of the archipelago.
These Galapagos rats feed primarily on the eggs of sea turtles and wild Galapagos tortoises, as well as on several plants that are an important food source for many species. The natural reproduction of turtles and tortoises has not been successful in many islands due to the presence of rats, but hopefully in a near future, with the efforts of the Galapagos Park Directive, working closely with the Ministry of Environment, NGOs and other multilateral international cooperation, the threat of these invasive species will be controlled.
The fight to control the introduced rat population in Galapagos today has expanded to include aerial fumigation with helicopters, spreading blue poison around the Island of Pinzon. The project aims to exterminate over 180 million rats that currently live on this island. However, by 2014, the rat free project will expand to include larger islands such as Floreana. To restore the ecosystem of the islands, affected by the aggressive predation of these animals, control programs are being carried out every year to prevent and eradicate rats permanently on different islands.
There are more than 500 species of animals in the Galapagos Islands between vertebrates and invertebrates. However, several invasive species have colonized and made their home, many protected areas of the islands. The 11 current invasive species in Galapagos are: rodents, ants, anis, the Philornis fly, the fruit fly, donkeys, pigs, feral cats, goats, the African snail and frog Scinax quinquefasciatus.
Animals that currently cause direct damage to the fauna of the islands are the black rat, the house mouse, the brown and bighead rat and the fire ant. Rodents and insects in particular, attack the nests of turtles, tortoises and iguanas, breaking open the eggs and killing the embryos instantly. The Galapagos National Park has been mainly focusing on these species as part of its most recent control and eradication program, but it is also fighting to eradicate the African snail, which is a threat to native flora, plants and fauna that are endemic to the islands.