Exotic Fauna

Many plants and animals are assumed to belong to the Mauritian ecosystem. In fact, they were deliberately or accidentally introduced to the island by man. The alien species displace native species through competition for limiting resources, they may prey upon native species to the point of extinction, such as the Dodo, they may alter the habitat so much that natives are no longer able to persist. For example, Dutch colonisers introduced the Rusa deer from Indonesia and East Timor in 1639, and grazing by these deer hinders native forest regeneration and helps spread invasive plants, such as Chinese guava. With settlements increasing in Mauritius, the need for food increased and more exotic animals were introduced-goats, pigs, cattle and dogs, ate the native vegetation and wildlife. Millions of rats found their way onto the island. Soon cats and mongooses were introduced to control rats, but ended up eradicating many endemic species. Even today, exotic animals continue to threaten the survival of many native plants and animals. Long-tailed macaques directly competes with the endemic fruit bat for food resources in the forest. Macaques are responsible for damaging majority of the forests’ reproductive outputs (i.e., flowers and fruits) and hinders forest regeneration.

Black Rat

  • Scientific name: Rattus rattus
  • Year of introduction: 1400
  • Reason for introduction: rats were accidentally introduced by escaping from ships docking the island
  • Impact:
    • Destroy native seeds and seedlings inhabiting forest regeneration
    • Disrupt pollinator mutualism of native plants by robbing flower nectar
    • Destroy endemic tortoise’s eggs and kill youngs
    • Kill native birds by feeding on the eggs and young
    • Compete with native wildlife by eating invertebrates.

The Dutch finally abandoned Mauritius in 1710 in part as a result of the loss of food crops due to the huge numbers of rats on the island.


  • Scientific name: Felis catus
  • Year of introduction:  c. 1688
  • Reason for introduction: Cats were introduced to Mauritius to reduce the number of rats on the island
  • Impact:
    • Kill native land birds, seabirds and reptiles

Cats have contributed to the extinction of at least 63 animals in the world.

Long-tailed macaques

  • Scientific name: Macaca fascicularis
  • Year of introduction: c. 1606
  • Reason for introduction: monkeys were intentionally introduced as pets to the island.
  • Impact:
    • Destroy native seeds and seedlings inhabiting forest regeneration
    • Disperse exotic seeds
    • Kill native birds by feeding on the eggs, young and adults
    • Destroy orchids and ferns
    • Compete with native wildlife by eating invertebrates
    • Compete directly with endemic fruit bats for food resources
    • Consume agriculturally important plant species and damage crops

This monkey is also known as the crab-eating macaque because it eats crabs in its native Southeast Asia. Brought aboard ships as pets, some monkeys caused so much trouble, they were abandoned on islands. They have a preference for secondary habitats which have been disturbed by human activity and are highly adaptive to new environments. Despite being one of the most invasive mammals in Mauritius, the long-tailed macaque is viewed as a religious form and doted upon by locals and tourists.

The small Indian Mongoose

  • Scientific name: Herpestes auropunctatus
  • Year of introduction:  1900
  • Reason for introduction: introduced as biocontrol agents to control population of rats.
  • Impact:
    • Kill native birds by feeding on the eggs, young and adults
    • Predates on native snails

Following a plague epidemic in 1899, the Mauritian authorities brought in 20 male individuals to help control the rat population. Unfortunately, the 20 individuals were not all male – it is believed that there were in fact three females; this led to the widespread proliferation of the species throughout the island.

The Rusa Deer

  • Scientific name: Cervus timorensis
  • Year of introduction: 1639
  • Reason for introduction: introduced as livestock and became the quarry in organized hunts.
  • Impact:
    • Destroy native seedlings and plants by grazing and trampling.
    • Hinders forest regeneration.
    • Damage trees, especially saplings, when male deer rub their antlers against trunks
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