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Sturnira magnagreater yellow-shouldered bat

By Josh Nimchuk

Geographic Range

Greater yellow-shouldered bats are found in South America, often along the northern Andes Mountains or in forests near the Amazon River. Specifically, they are found in south-central Columbia, eastern Ecuador and Peru, and northwestern Bolivia. (Tamsitt and Hauser, 1985)

Habitat

Greater yellow-shouldered bats are commonly found on the eastern slopes of the northern Andes Mountains in montane forests. They are also found in tropical forests near the Amazon River. They prefer undisturbed tropical forests for nesting sites, but specific roosting sites are unknown. Greater yellow-shouldered bats are most often found in tropical forests where the mean annual precipitation is greater than 400 cm and the mean annual temperature is greater than 24 degrees Celsius.

In Bolivia greater yellow-shouldered bats are typically found at elevations of 685 to 1650 m but have been recorded as high as 2300 m. In Columbia and Peru they are typically found below 300 m in tropical rainforests by the Amazon River. There appears to be a vertical range pattern associated with latitude. In areas north of 5 °S, their vertical range is 100 to 915 m. Areas south of 5 °S, their vertical range is expanded to 200 to 2300 m.

This species is often found in similar areas as Sturnira lilium, which often roost in hollow trees. Sturnira magna may also roost in hollow trees. (Anderson, et al., 1982; Lee, et al., 2006; Tamsitt and Hauser, 1985)

  • Range elevation
    100 to 2300 m
    328.08 to 7545.93 ft

Physical Description

Greater yellow-shouldered bats in the southern part of their range have a yellow-brown pelage. In the northern part of their range, pelage is browner. Dorsal hairs are gray or yellow at the base and brown or gray at the tip. Greater yellow-shouldered bats often have spots at the shoulders, from which the common name is derived. Ventral pelage is pale yellow or brown, is darker toward the posterior, and is paler than the dorsal side. Individual hairs are tricolored.

Greater yellow-shouldered bats are tailless and have a reduced uropatagium. Like all members of Sturnira, this species has a enlarged third digit. They weigh from 43.1 to 50.0 g and measure 85 to 90 mm in length. Males tend to be slightly larger than females and have slightly longer skulls and a longer maxillary toothrow. Females occasionally have yellowish-brown hairs on their shoulders.

Greater yellow-shouldered bats have trilobed incisors. The dental formula is I2/2, C1/1, P2/2, M3/3 for a total of 32 teeth. The presence of two lower incisors distinguishes S. magna from two other species in the genus Sturnira. Well developed cusps on the first two molars distinguish this species from five other species in the genus. (Marinkelle and Cadena, 1972; Tamsitt and Hauser, 1985; Tamsitt, et al., 1986)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • Range mass
    43.1 to 50.0 g
    1.52 to 1.76 oz
  • Range length
    85 to 90 mm
    3.35 to 3.54 in

Reproduction

Little is known about the mating behavior of greater yellow-shouldered bats.

Little is known regarding the reproductive behavior of greater yellow-shouldered bats. In a related species, Sturnira lilium, reproduction occurs twice a year, once in the dry season and once in the wet season. Gestation of S. lilium produces a single offspring each breeding season for an annual total of two pups. Pregnant greater yellow-shouldered bats have been found in February (dry season) and May (wet season) indicating a similar reproductive pattern. Lactating females have been captured in Columbia in May. Males with enlarged testes have been found in May and July. (Stoner, 2001; Tamsitt and Hauser, 1985)

  • Breeding interval
    Greater yellow-shouldered bats are thought to reproduces once in the wet season and once in the dry season.
  • Breeding season
    The specific breeding seasons of greater yellow-shouldered bats are unknown.

Little is known regarding parental investment of greater yellow-shouldered bats. As mammals, females lactate until pups are weaned.

  • Parental Investment
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female

Lifespan/Longevity

Lifespan of greater yellow-shouldered bats is currently unknown. Sturnira lilium can live approximately 20 years in the wild. (Grzimek, 1990)

Behavior

Although they have a wide distribution and presumably have a large population, little is known about the biology or behavior of greater yellow-shouldered bats.

Home Range

Range size of greater yellow-shouldered bats is currently unknown.

Communication and Perception

Like all Phyllostomids, greater yellow-shouldered bats echolocate. Other species in the genus Sturnira tend to have low intensity, high frequency patterns that are less specialized than those of insectivorous species due to the sessile nature of their food. This is common in bats that forage under the canopy. Echolocation, however, has not been studied specifically in Sturnira magna. (Tamsitt and Hauser, 1985)

Food Habits

Greater yellow-shouldered bats are low flying frugivores. They feed alone at night and pick fruits from trees. They consume picked fruits away from the tree. Greater yellow-shouldered bats consume fruits from the family Solanacea and have been captured near gardens containing bananas (Musa) and papaya (Carica papaya). A similar species, Sturnira erythromos, feeds on fruits of the genus Solanum. (Giannini and Barquez, 2003; Pacheco, et al., 2008; Patterson, 1996; Tamsitt and Hauser, 1985)

  • Plant Foods
  • fruit

Predation

Predators of greater yellow-shouldered bats are currently unknown.

Ecosystem Roles

Sturnira magna is a frugivore and likely plays a role in seed dispersal for the plants on which they feed. Greater yellow-shouldered bats are parasitized by Anastrebla delatorrei and Capillaria. (Nogueira, et al., 2003; Tamsitt and Hauser, 1985)

  • Ecosystem Impact
  • disperses seeds
Commensal/Parasitic Species
  • Anastrebla delatorrei
  • Capillaria

Economic Importance for Humans: Positive

Positive impacts of greater yellow-shouldered bats on humans are unknown.

Economic Importance for Humans: Negative

There are no known adverse effects of greater yellow-shouldered bats on humans.

Conservation Status

In 2008, Sturnira magna was declared a species least concern by the IUCN. Its wide distribution makes the species unlikely to be declining at a fast rate. In Bolivia, however, S. magna is considered vulnerable due to habitat loss by deforestation. (Pacheco, et al., 2008)

Other Comments

The specific epithet, magna, refers to the large size of Sturnira magna within the genus Sturnira. (Tamsitt and Hauser, 1985)

Contributors

Josh Nimchuk (author), University of Manitoba, Jane Waterman (editor), University of Manitoba, Gail McCormick (editor), Animal Diversity Web Staff.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

echolocation

The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

References

Anderson, S., K. Koopman, G. Creighton. 1982. Bats of Boliva: An annotated checklist. American Museum Novitates, 2750: 1-24.

Giannini, N., R. Barquez. 2003. Sturnira erythtomos. Mammalian Species, 729: 1-5.

Grzimek, B. 1990. Bats. Pp. 584-611 in B Grzimek, ed. Grzimek's Encyclopedia of Mammals, Vol. 1, 2 Edition. New York, NY: Mcgraw-Hill Publishing Co.

Lee, T., A. Diego, R. Platt, G. Goodwiler. 2006. Report on a mammal survey of the Cosanga River Drainage, Ecuador. Occasional Papers, Museum of Texas Tech University, 260: 1-10.

Marinkelle, C., A. Cadena. 1972. Notes on bats new to the fauna of Columbia. Mammalia, 36: 50-58.

Nogueira, M., S. de Fabio, A. Peracchi. 2003. Gastrointestinal helminth parasitism in fruit-eating bats (Chiroptera, Sternomatinae) from western Amazonian Brazil. International Journal of Tropical Biology and Conservation, 52: 387-392.

Pacheco, V., L. Aguirre, H. Mantilla. 2008. "Sturnira magna" (On-line). In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. Accessed November 05, 2011 at http://www.iucnredlist.org/apps/redlist/details/20956/0.

Patterson, B. 1996. Distributions of bats along an elevational gradient in the Andes of south-eastern Peru. Journal of Zoology, 240: 637-658.

Peterson, R., J. Tamsitt. 1968. A new species of bat of the genus Sturnira (Family Phyllostomatidae) from northwestern South America. Life Sciences Occasional Papers, Royal Ontario Museum, 12: 1-8.

Stoner, K. 2001. Differential habitat use and reproductive patterns of frugivorous bats in tropical dry forest of northwestern Costa Rica. Canadian Journal of Zoology, 79: 1626-1633.

Tamsitt, J., A. Cadena, E. Villarraga. 1986. Records of Bats (Sturnira magna and Sturnira aratathomasi) from Columbia. Journal of Mammalogy, 67: 754-757.

Tamsitt, J., C. Hauser. 1985. Sturnira magna. Mammalian Species, 240: 1-4.

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