Its reputation as a slayer of serpents has helped the mongoose gain fame as well as new territory. The family Herpestidae has 14 genera and 34 species, none of which are found outside Africa and Eurasia. Again, it is the genus Herpestes (6 species of which are native to South Asia) that has benefited. While the legends of snake-killing are said to be inspired by the abilities of the Indian Grey Mongoose (Herpestes edwardsii), it is a smaller cousin that has made the most of that reputation, the Small Asian Mongoose (Herpestes auropunctatus). It has spread to island groups scattered across the globe; no mean achievement for so diminutive a creature.

The natural range of the Small Asian Mongoose forms an arc stretching across the southern half of Asia, from Iraq in the west, over Iran, Afghanistan, South Asia, and on to Myanmar in the east. In contrast to the much larger Indian Grey Mongoose (around 90 cm long from nose to tail, and as much as 1.7 kg in weight), it is a lightweight – just 67 cm and 660 g. A diurnal species with a preference for dry forests, scrub and grasslands, the Small Asian Mongoose feeds on insects, arachnids, crustaceans, amphibians, lizards, snakes, ground dwelling birds and rodents. Fruits are also consumed.

It was this voracious diet of farm pests that encouraged some humans to introduce the species to far away lands. The intentions were good – controlling rats and snakes that had gone on a rampage. But the results were mixed at best, and a total disaster at worst. While the mongoose’s ability to control its intended targets began to be questioned, its impact on native wildlife was deemed to be negative. The debate rages on but the Small Asian Mongoose has managed to earn the dubious sobriquet of being one of the 100 Worst Invasive Species of the World (according to a IUCN report in 2014).

Where did all of this begin? Back in the 19th century, when rodents were threatening to destroy the very basis of many island economies – the sugarcane plantations of the Caribbean and the South Pacific. The first successful introduction of Herpestes auropunctatus took place when a batch of four males and five females were shipped from Calcutta (present-day Kolkata), Bengal to the island of Jamaica. These Jamaican mongooses were then sent to Cuba, Puerto Rico, the Virgin Islands, Barbados, Grenada, and Trinidad & Tobago. In 1883, 72 individuals were sent all the way from Jamaica to the island chain of Hawaii, establishing the first Pacific population.

Fiji (in the South Pacific), Mauritius (off the east coast of Madagascar, in the Indian Ocean) and the Ryuku Islands (between Japan and Taiwan, also in the Pacific) received batches of  Small Asian Mongooses in 1883, 1900 and 1910, all from South Asia. While the primary aim was to bring the population of rats in sugarcane fields under control, mongooses were also introduced to keep a check on poisonous snakes such as the Okinawa Habu (Trimeresurus flavoviridis of the Ryuku Islands), the Martinique Lancehead (Bothrops lanceolatus of Martinique), the St. Lucia Lancehead (Bothrops caribbaeus of  St. Lucia) and Sand Viper (Vipera ammodytes of the Balkans).

Here’s a brief list of territories which have fallen under the sway of Herpestes auropunctatus:

  • The Caribbean (Cuba, Jamaica, Hispaniola, Puerto Rico, the Virgin Islands, St. Kitts & Nevis, St. Martin, Antigua & Barbuda, Guadeloupe, Martinique, St. Lucia, St. Vincent & the Grenadines, Barbados, Grenada, Trinidad & Tobago)
  • South America (French Guiana, Suriname, Guyana)
  • Pacific (Hawaii, Samoa, Fiji, New Caledonia, Ryuku Islands)
  • Africa (Mauritius, Grand Comore Island of the Comoros, Mafia Island of the Zanzibar Archipelago)
  • Europe (Croatia, Bosnia-Herzegovina)

Its range might have expanded but its reputation has taken a hit. First of all, it did not take out the rats the way it was supposed to. But one cannot blame the little critter alone. Overenthusiastic proponents of biocontrol forgot to take into account the targeted rodents’ ability to switch to nocturnal mode in the presence of diurnal predators. The Small Asian Mongoose itself had no predator to keep it under check on the islands, and its population increased rapidly, thanks to flexible food habits and prolific breeding. Soon, it had become a problem, hunting down poultry and defenseless native species, especially ground-dwelling fauna.  The Bar-Winged Rail (Nesoclopeus poecilopterus) of Fiji and the Jamaican Petrel (Pterodroma caribbaea) are believed to have gone extinct on account of mongoose predation.

Others creatures put at risk by its wayward behaviour are listed below:

  • The Caribbean: Green Iguana (Iguana iguana), St. Croix Ground Lizard (Ameiva polops), Hawksbill Turtle (Eretmochelys imbricata), Leatherback Turtle (Dermochelys coriacea)
  • Hawaii: Hawaiian Goose (Branta sandvicencis), Hawaiian shearwater (Puffinus newelli)
  • Ryuku Islands: Amami Rabbit (Pentalagus furnessi), Lidth’s Jay (Garrulus lidthi), Ryuku Robin (Larvivora komadori), Okinawa Rail (Gallirallus okinawae)
  • Mauritius: Pink Pigeon (Nesoenas mayeri), Mauritian Kestrel (Falco punctatus)

Image Attribution: The image above was taken from Wikimedia Commons and depicts an Indian Grey Mongoose (Herpestes edwardsii). The illustration by Dutch artist Joseph Smit appeared in the Proceedings of the Zoological Society of London, in 1874.