Japanese noctule  (Nyctalus furvus)

The Japanese noctule is classified as Vulnerable (VU) on the IUCN Red List (1).

The enigmatic Japanese noctule (Nyctalus furvus) is a small, poorly understood species of bat from Japan (2). It belongs to the Vespertilionidae family, a large group of over 308 bat species also known as the vesper bats (3).

Very little information exists on the elusive Japanese noctule, but, like other vesper bats, it has a well-developed tail and minute eyes. The ears are widely separated on the head and possess a tragus. The fur may be golden brown, yellowish-brown or dark brown on the upperparts, and a paler brown on the underparts (4).

As its name suggests, the Japanese noctule is only found in Japan. It occurs in four separate populations (1), all of which are located in the north of Honshu (5), the largest island of Japan.

The Japanese noctule inhabits primary forest. It typically roosts in tree hollows, although one colony was found in a building (1). The island of Honshu has a mainly subtropical climate, although the northern extremity has snowy winters (6).

The Japanese noctule is an insectivorous species (4). Although little is known of the specific diet of the Japanese noctule, it is likely to be similar to that of closely related bats. Noctule bats (Nyctalus species) are typically fond of beetles, catching them midflight (4) (7), but they may also eat moths, winged ants and other insects (4). Noctule bats typically hunt for prey during flights just before sunrise and in the early evening (4).

Bats in the Vespertilionidae family typically mate in the autumn, prior to hibernation. The sperm remains viable in the oviduct of the female, until the female is aroused from hibernation in early spring, when the female ovulates and fertilisation then occurs (8).

Pregnant females often roost together in large colonies of up to 400 individuals, while the males roost separately (4). Each female bat gives birth between 1 and 3 young in the spring (4), after a gestation period of 70 to 75 days (4). Bats in the Vespertilionidae family can live for up to 30 years (9).

Although accurate information on the Japanese noctule population is lacking, numbers are thought to be in decline (1). This species faces the threat of deforestation for logging, agriculture and conifer plantations, as well as for the general development of infrastructure in the region (1).

There are no known conservation measures currently in place for the Japanese noctule.

Find out about bat conservation:

• Bat Conservation Trust:
  http://www.bats.org.uk/
• Bat Conservancy:
  http://www.batconservancy.org/