Black myotis (Myotis nigricans)

Description

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Black myotis fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Black myotis description

The black myotis (Myotis nigricans) is a relatively small bat, aptly named for its blackish fur ^{(2) (3)}. However, its colouration can also vary from dark brown to light- or reddish-brown, and the underparts may be brown, cream or buff ^{(2) (3) (4) (5)}. The wing and tail membranes, face and ears are blackish ^{(3) (4)}.

The fur of the black myotis is smooth and somewhat silky. The tail is relatively long, but is entirely enclosed within the tail membrane, which is naked from below the level of the knees ^{(2) (3) (4)}. The black myotis has tiny eyes, narrow, pointed ears, a pointed tragus in front of each ear, and no noseleaf ^{(3) (4)}. The female black myotis is usually slightly larger than the male ^{(5) (6)}.

A number of subspecies of the black myotis have been identified ^{(2) (7) (8) (9)}. However, its taxonomy is poorly understood and further study may reveal it to comprise more than one distinct species ^{(7) (9)}.

Synonyms

Myotis bondae, Myotis caucensis, Myotis chiriquensis, Myotis esmeraldae, Myotis maripensis, Myotis nigracans, Myotis punensis, Phyllostomus quixensis, Vespertilio arsinoë, Vespertilio brasiliensis, Vespertilio concinnus, Vespertilio exiguus, Vespertilio hypothrix, Vespertilio mundus, Vespertilio nigricans, Vespertilio osculatii, Vespertilio parvulus, Vespertilio spixii, Vespertilio splendidus.

Size

Head-body length: 3.8 - 5.2 cm ^{(2) (3)}

Tail length: 2.8 - 4.4 cm ^{(2) (3)}

Forearm length: 3.3 - 3.8 cm ⁽³⁾

Weight

3 - 6 g ^{(2) (3)}

Black myotis biology

The diet of the black myotis consists predominantly of flying insects, including moths, beetles and flies ^{(1) (3) (10) (12)}. This species flies quickly, with rapid wingbeats ⁽⁴⁾, and captures its prey in the tail membrane before transferring it to the mouth ⁽¹¹⁾. Foraging takes place at night ^{(1) (2) (3) (10)}. The black myotis roosts by day in large clusters of females and young, with the males usually roosting alone or in separate bachelor groups ^{(2) (3) (5)}.

In Panama, the black myotis mate in December and January, with most births occurring around February, after a gestation period of around 60 days. The females immediately become receptive again after giving birth, and further birth peaks occur between April and May and again in August. However, breeding does not then resume until December, ensuring that no young are weaned in the dry season between January and March, when insects are scarce ^{(2) (3) (5) (10)}. In other parts of the black myotis’ range, birth peaks may occur at different times of the year ^{(5) (10)}.

The black myotis usually gives birth to a single young at a time ^{(5) (10)}. The young bat remains attached to the female for the first two or three days, after which it is left behind in a large group, or crèche, while the female leaves the roost to feed ^{(2) (5) (13)}. The young black myotis is able to fly for the first time from just three weeks old ^{(2) (5)}, but weaning does not occur until about five to six weeks ^{(2) (10)}. This species reaches sexual maturity at around four months and has been known to live for up to seven years in the wild ^{(2) (5)}.

Black myotis range

The black myotis is found in most of Central and South America, where it is reported to be the most abundant and widespread Myotis species ⁽⁷⁾. Its distribution extends from Nayarit and Tamaulipas in Mexico, south to northern Argentina, and also includes Trinidad and Tobago, Montserrat and Grenada in the Caribbean ^{(1) (3) (5) (7) (9) (10)}.

Black myotis habitat

This species occurs in a wide range of habitats, including most types of tropical and subtropical forest, as well as agricultural areas, gardens, savanna and scrub ^{(1) (2)}.

The black myotis prefers to forage in open areas or gaps in the forest, such as those formed by streams, trails or fallen trees, and even uses clearings around buildings ^{(1) (4) (11)}. It usually roosts in hollow trees, rock crevices, caves or buildings ^{(1) (3) (4) (10)}, and has been recorded up to elevations of 3,150 metres ^{(2) (3)}.

Black myotis status

The black myotis is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Black myotis threats

With its large population and widespread distribution, the black myotis is not currently considered at risk of extinction. It is not known to face any major threats, and appears to be relatively resilient to the modification of its habitat ⁽¹⁾.

Black myotis conservation

The black myotis occurs in several protected areas, but there are no specific conservation measures currently targeted at this species. Some populations may need extra protection, such as the northern population in Mexico, which is a potential subspecies ⁽¹⁾.

The taxonomy of the black myotis also needs to be revised as, if it does comprise more than one distinct species, the conservation needs of the different forms may potentially need to be reassessed ⁽¹⁾.

ARKive is supported by OTEP, a joint programme of funding from the UK FCO and DFID which provides support to address priority environmental issues in the Overseas Territories, and Defra

Find out more

Find out more about bat conservation:

• Bat Conservation International:
  http://www.batcon.org/
• Organisation for Bat Conservation:
  http://www.batconservation.org/

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arkive@wildscreen.org.uk

Glossary

Gestation

The state of being pregnant; the period from conception to birth.

Noseleaf

A fleshy structure surrounding the nose, common to many bats. It is believed to function in focusing echolocation calls (high-pitched calls used in orientation and to locate prey) emitted from the nose.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

Taxonomy

The science of classifying organisms, grouping together animals which share common features and are thought to have a common ancestor.

Tragus

A soft cartilaginous projection extending in front of the external opening of the ear. In bats, it plays an important role in filtering returning echoes in echolocation.

References

1. IUCN Red List (February, 2011)
   http://www.iucnredlist.org/
2. Wilson, D.E. and LaVal, R.K. (1974) Myotis nigricans. Mammalian Species, 39: 1-3. Available at:
   http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-039-01-0001.pdf
3. Reid, F.A. (2009) A Field Guide to the Mammals of Central America and Southeast Mexico. Second Edition. Oxford University Press, New York.
4. Emmons, L.H. (1997) Neotropical Rainforest Mammals: A Field Guide. Second Edition. University of Chicago Press, Chicago.
5. Eisenberg, J.F. and Redford, K.H. (2000) Mammals of the Neotropics. Volume 3. The Central Neotropics: Ecuador, Peru, Bolivia, Brazil. University of Chicago Press, Chicago.
6. Bornholdt, R., Oliveira, L.R. and Fabián, M.E. (2008) Sexual size dimorphism in Myotis nigricans (Schinz, 1821) (Chiroptera: Vespertilionidae) from south Brazil. Brazilian Journal of Biology, 68(4): 897-904.
7. Gardner, A.L. (2008) Mammals of South America. Volume 1: Marsupials, Xenarthrans, Shrews, and Bats. University of Chicago Press, Chicago.
8. Hall, E.R. and Alvarez, T. (1961) A new subspecies of the black myotis (bat) from eastern Mexico. Universityof Kansas Publications, Museum of Natural History, 14(4): 69-72.
9. Wilson, D.E. and Reeder, D.M. (2005) Mammal Species of the World. A Taxonomic and Geographic Reference. Third Edition. The Johns Hopkins University Press, Baltimore. Available at:
   http://www.bucknell.edu/MSW3/
10. Nowak, R.M. (1991) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
11. Siemers, B.M., Kalko, E.K.V. and Schnitzler, H-U. (2001) Echolocation behavior and signal plasticity in the Neotropical bat Myotis nigricans (Schinz, 1821) (Vespertilionidae): a convergent case with European species of Pipistrellus? Behavioral Ecology and Sociobiology, 50(4): 317-328.
12. Aguiar, L.M.S. and Antonini, Y. (2008) Diet of two sympatric insectivores bats (Chiroptera: Vespertilionidae) in the Cerrado of Central Brazil. Revista Brasileira de Zoologia, 25(1): 28-31.
13. Wilson, D.E. (1971) Ecology of Myotis nigricans (Mammalia: Chiroptera) on Barro Colorado Island, Panama Canal Zone. Journal of Zoology, 163(1): 1-13.