The Jeju Striped Field Mouse, or Apodemus chejuensis, is a field mouse

Field mouse

Field mouse may refer to:*in Europe, Asia and north Africa, one of several species of mice in genus Apodemus*in North America, a small vole such as the Meadow Vole*in South America, one of several species of mice in genus Akodon...

 found only on Jejudo

Jeju-do

Jeju-do is the only special autonomous province of South Korea, situated on and coterminous with the country's largest island. Jeju-do lies in the Korea Strait, southwest of Jeollanam-do Province, of which it was a part before it became a separate province in 1946...

, an island in the northern East China Sea

East China Sea

The East China Sea is a marginal sea east of China. It is a part of the Pacific Ocean and covers an area of 1,249,000 km² or 750,000 square miles.-Geography:...

 off the southwestern coast of South Korea

South Korea

The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...

. It was originally described in 1965 as a subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of Apodemus agrarius. However, a 1992 study of mitochondrial DNA

Mitochondrial DNA

Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...

 found that it was in fact a separate species.

The Jeju Striped Field Mouse is one of the most abundant mammals on Jeju. It has brown fur with an eel back, hence the name.