After five years without a sighting, the rare 'golden bat' reemerges in Jeju lava tubes

The endangered species Reddish-black myotis, known as the "golden bat" and designated as a natural monument, has been found on Jeju Island.

Reddish-black myotis, otherwise known ″golden bat,″ hangs from a cave ceiling. [JEJU WORLD NATURAL HERITAGE CENTER]

The endangered Reddish-black myotis, known as the "golden bat" and designated as a natural monument, has been found on Jeju Island.

The Jeju World Natural Heritage Center said Monday that it confirmed the presence of a hibernating Reddish-black myotis during routine monitoring of the Gimnyeonggul Lava Tube cave last month. The cave is a Unesco World Natural Heritage site on Jeju Island.

Belonging to the Vespertilionidae family, the bat has a body length of 4 to 6 centimeters (1.57 to 2.36 inches) and is distinguished by its deep orange body and black wings, earning it the golden bat moniker.

Designated as a natural monument in 2005, the golden bat is classified as a Category One endangered species in Korea.

The golden bat was first sighted in an undisclosed section of Manjanggul Lava Tube, near the Gimnyeonggul Lava Tube, in 2008. Its presence was observed each winter until 2019.

This recent discovery marks the first sighting in Gimnyeonggul Lava Tube in seven years. The cave, located 500 to 600 meters (1,640 to 1,968 feet) from Manjanggul Lava Tube, recorded sightings of the golden bat during the winters of 2015 and 2016, and once more in the spring of 2017.

The Jeju World Natural Heritage Center speculates that the Geomunoreum Lava Tube System, also a Unesco World Natural Heritage site, provides a suitable habitat for the bat, allowing it to expand its range to nearby caves.

Both Gimnyeonggul and Manjanggul Lava Tubes have multiple entrances and maintain stable conditions year-round, with winter temperatures around 10 degrees Celsius (50 degrees Fahrenheit) and humidity levels above 95 percent. These conditions create an ideal environment for the Reddish-black myotis to hibernate.

Unlike other bats, the golden bat is especially sensitive to temperature and humidity, which has contributed to a decline in its habitats nationwide. However, Jeju's lava tubes, being a World Natural Heritage site with restricted access, have helped preserve the bat’s habitat.

“We plan to continue monitoring to ensure a safe wintering period for the Reddish-black myotis,” said an official from the Jeju World Natural Heritage Center.

“We are committed to preserving and managing the Geomunoreum Lava Tube System, a World Natural Heritage site, as a stable habitat for diverse species.”

BY KIM MIN-YOUNG [kim.minyoung5@joongang.co.kr]