Mongooses in Hawaii: Why Latest Find on Kauai Is So Disturbing

Mongooses in Hawaii are a big problem and even more so on Kauai which has been relatively free of them. The small Indian mongoose is native to Asia and was intentionally brought to other places including the Caribbean and Hawaii.

These animals which look like a weasel and are about 2 feet in length, low to the ground, and with a long tail, are considered opportunistic feeders. They sleep in dens at night and are active during daylight hours. We’ve seen them frequently on the Big Island.

Impacts of Mongoose invasive species throughout most of Hawaii.

The small mongooses eat birds and their eggs, in addition to other small animals, plants, fruits, and insects. The problem here is that they prey on the endangered Hawaiian sea turtles and native ground-nesting birds. They are already implicated in the deaths of 8 species of federally endangered Hawaiian birds, including the Hawaiian crow, petrels, and the Hawaii state bird (Nene).

Kauai has been largely free of mongooses up until now and we hope that continues to be the case.

Another mongoose was found this week on Kauai.

A mongoose was trapped this week for the first time in five years. It was captured at the Nawiliwili boat harbor after being spotted by state workers and subsequently reported to the Department of Agriculture. 15 traps were set Monday and the animal was caught on Tuesday. The state plans to keep the traps in place to determine if other mongooses are present.

Mongooses in Hawaii: brought to sugar plantations to control rat populations.

The mongooses here were imported from Asia via Jamaica in the late 1800s by individuals in the sugarcane industry, initially to the Hamakua Coast on the Big Island, in the false belief that they would control the rat problem in the cane fields on Molokai, Maui, and Oahu.

The introduction to Hawaii Island was not done scientifically based on research and was instead an ad-hoc, misguided effort. While they may have eaten some rats, they didn’t control the rodents and instead had a highly deleterious impact on important birds, insects, and other animals. Mongoose became rampant on the Big Island in addition to the other three islands where they were introduced.

One serious mistake was that rats are nocturnal whereas mongooses are diurnal. Therein the two populations are not typically active at the same time.

Keeping a mongoose is subject to a $1,000 fine per mammal, other than by permit.

No known mongoose populations exist on Kauai or on Lanai.

In 1976, a female mongoose was found dead on rural Kauai. Sightings have been reported elsewhere, and in 2012, a live one was captured near the airport. followed by another at Nawiliwili Harbor. Until this latest incident, the last one captured was in 2016, which was also near the airport. The state is still trying to determine whether any population of animals exists.

Folklore had it that when mongooses bound for Kauai arrived in the late 1800s, a dock worker handling them was bitten. He allegedly threw the container of animals into the water, killing them.

Don’t mistake a cat or a rat for a mongoose. Look for the short legs.

Keep in mind that mongooses are largely only active during the day while cats are active at night. Also, the mongoose has a brownish body, a long head with a pointed nose, and holds its tail level with the ground, whereas cats typically hold their tails at angles. Rats, another invasive species that was introduced to Hawaii are much smaller than mongooses and are again largely nocturnal.