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The Hawaiian Hoary Bat

The Amazing Hawaiian Hoary Bat

Many visitors to Hawaii will find the Aloha State offers many wonderfully unique things to see as well as experience. And if they are lucky, they might be able to see the rare Hawaiian hoary bat or ope’ape’a. Ope’ape’a means half-leaf in Hawaiian. This name refers to the shape of the bat’s body which resembles half of a taro leaf.

Hawaiian Only Endemic Land Mammal

This rarely seen animal is Hawaii’s only endemic land mammal. This means one cannot find it anywhere else in the world. It is only one of two endemic mammals in the state. The other is the Hawaiian monk seal. The Hawaiian hoary bat has been an endangered species since 1970. Hawaii recently designated it as its official State land mammal in 2015.

The ope’ape’a is a sub-specie of the hoary bat that lives on the American continents. But unlike its mainland cousin, scientists know very little about the Hawaiian hoary bat. Recent DNA sequencing evidence reveals that the bat’s ancestors came from the Pacific coast of North America. They came in two separate waves, 9,000 years apart.

The ope’ape’a’s diet consists of insects which they hunt for only during nights. It can eat up to 40% of its weight in bugs in a single night. The typical ope’ape’a weighs about half an ounce and has wingspans ranging from 10.5 to 13.5 inches.

How it Came to Hawaii

It is Hawaii’s only endemic land mammal. But the ope’ape’a is also remarkable in that its ancestors had to fly at least 2,300 miles from North America to get here. This would make it the known longest migration for any type of bat. Scientists believe the Hawaiian hoary bat’s ancestors would have had the capability of flying such distances. This would be achievable, particularly if strong storm winds aided them over the Pacific Ocean.

Where It Lives Today

Fossil records indicate the ope’ape’a once lived on all of the main Hawaiian Islands, except for Kahoolawe and Niihau. But today, one can mainly see them on Kauai, Maui and on the Big Island of Hawaii. On the Big Island, there are less sightings of the ope’ape’a along the coasts during the months of January through April. This suggests that they are migrating to the higher elevations on Mauna Kea and Mauna Loa. This is where the bats can enjoy cooler temperatures. In turn, this allows them to lower their metabolic rates while resting. The ope’ape’a small size and few number of sightings make these bats very difficult to study. So it is unknown whether the population of the ope’ape’a are increasing or decreasing.