The problems worldwide caused by introduced rats, mainly in crops and as vectors for diseases which affect man and other animals, started thousands of years ago. In the Galapagos Islands introduced rats were probably brought in pirate boats at the end of the seventeenth century, and sporadically with the subsequent colonists.Rodents are carriers of many human and animal diseases, caused by ecto-parasites (fleas and ticks), viruses (for example hantavirus), bacteria (for example Leptospira) and protozoans (for example Toxoplasma gondii). Toxoplamsis can cause ocular and cerebral damage in adults and fetuses and salmonella infection can cause high fevers, body pains, diarrhoea and in some cases, meningitis. These diseases can be transmitted to man via contact with rodent feces, urine, saliva, or in the case of some viruses, inhaling them in aerosol form.
Rodent control is the best means of preventing these diseases, especially in oceanic islands such as Galapagos which are
vulnerable to the introduction of new diseases. In addition, their unique fauna and flora are affected. In some cases,
they have resulted in the extinction of species.
Introduced rodents which have had the most negative impact are: the black rat (also known as the ship or roof rat) (Rattus rattus) and the Norwegian rat (also known as the brown or sewer rat) (Rattus norvegicus).
These two species of rodent, together with pigs and goats, are among the most damaging introduced mammals to native ecosystems. For this reason, with the objective of achieving the complete ecological recovery of one of the important islands in the Galapagos National park, Santiago Island, pigs have now been eradicated, the goat eradication is entering the final stage and eradication of the introduced rodents is the next step.
However, before this begins, eradication of black rats on off-lying islets is being carried out, so that these islets can be used as refuges and reproductive sites for the endemic rice rat of Santiago, Nesoryzomys swarthi. Therefore the GNP began the rat eradication on the Bainbridge rocks and up to now have managed to clear introduced rats from two of the four islets.
They will continue carrying out control on the other islets
Source: Galapagos National Park.