Small woolly bat (Kerivoula intermedia)

Also known as: Sabah forest bat
KingdomAnimalia
PhylumChordata
ClassMammalia
OrderChiroptera
FamilyVespertilionidae
GenusKerivoula (1)
SizeHead-and-body length: 30 - 40 mm (2)
Tail length: 24 - 42 mm (2)
Forearm length: 27 - 31 mm (2)
Weight2.5 - 4.0 g (2)

Classified as Near Threatened (NT) on the IUCN Red List (1).

This tiny bat is one of the smallest in the world, rivalling the famous bumblebee bat (Craseonycteris thonglongyai) of Thailand. In some areas in its range, the smaller individuals are considered to be of a separate species, Kerivoula minuta, but the distinction is not clear and further genetic and morphological investigation is necessary to determine the status of these two very similar species. The fur of the small woolly bat is orange-brown on the back and paler on the underside. The base of each hair is dark, as are the wing membranes (2).

Occurs in western Peninsular Malaysia and Borneo (3).

This highly manoeuvrable bat occupies the densely vegetated understorey of lowland dipterocarp forest as well as scrubland (4) (5). Its roosting preferences are unknown (2), but some suggest that it may roost in caves (5).

The small woolly bat feeds on small insects whilst in flight. It emits echolocation pulses through its mouth starting at 173 kHz and falling to 77 kHz immediately before a catch. The calls last just two milliseconds, but occur in groups of two to four (2). It is able to dodge leaves and branches in the densest forest using its short, wide wings (6).

Pregnancy most commonly occurs during February and May, and lactation is from May to July. There seems to be a second, smaller breeding season from August to October (2). Each female gives birth to a single pup, weighing around a quarter of her own weight. The pup accompanies its mother on foraging trips, at first clinging to her belly and later flying alongside as it learns to forage alone. At one year the pup becomes sexually mature (6).

The rapid increase in land devoted to growing oil palm has resulted in extensive loss of primary forest. Together, Malaysia and Indonesia export 88 percent of the world’s palm oil, for use in products such as margarine, lipstick and detergent. Deforestation continues at a steady rate for conversion to agricultural land and building communities, and despite the contribution of many bats in the control of insect crop pests, persecution of bats is also a threat (7).

Deforestation of primary forest for oil palm plantations, including within protected areas, is an issue of major concern and one that relies on both governmental action and consumer concern. Some large retailers have agreed, in collaboration with the WWF, to source products containing palm oil from plantations that are not on deforested land (7). Many scientific and charitable groups contribute to bat monitoring and local education programmes that can help to reduce persecution and raise awareness of the natural assets of the land (6).

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: arkive@wildscreen.org.uk

  1. IUCN Red List (June, 2009)
    http://ww.iucnredlist.org
  2. Kingston, T. (2005) Pers. comm.
  3. Nor, S. (1996) The Mammalian Fauna on the islands at the Nortern Tip of Sabah, Borneo. Fieldiana – Zoology, 83: 17 - 28.
  4. Kingston, T., Jones, G., Akbar, Z. and Kunz, T.H. (1999) Echolocation signal design in Kerivoulinae and Murininae from Malaysia. Journal of Zoology, 249: 359 - 374.
  5. Asean Regional Centre for Biodiversity Conservation (December, 2005)
    http://www.arcbc.org
  6. Maltby, A. (2005) Pers. comm.
  7. Europa World (January, 2005)
    http://www.europaworld.org/issue66/swisspalm25102.htm