Rattus rattus: Black Rat

Origin: India

Colonized areas: Throughout the world. For example: the United Kingdom, France, Italy, Spain, Belgium, Denmark, Portugal, Indonesia, Tanzania, Tunisia, Madagascar, Mauritania, the Seychelles Islands, La Réunion, the Caribbean Islands, the United States, Canada, Mexico, Chile, the Galapagos Islands, Australia, New Zealand, Papua New Guinea and at least 28 archipelagos in the Pacific.

Method of colonization: Accidental introduction via shipping containers and motor vehicles. Can also swim from one island to another.

Impacts: Directly contributed to the extinction of many bird, mammal, reptile, invertebrate and plant species, particularly in island populations. A vector of plague; responsible for certain recent outbursts in Madagascar.

Rate of reproduction: 7 young in a litter, gestation of 21 days, sexual maturity at 4 months. The female can have almost 200 babies during the life cycle (2 to 3 years).

Obstacles to eradication: Strong adaptability in all environments and high rate of reproduction.