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Leptonycteris nivalisMexican long-nosed bat

By Rosie Clarke

Geographic Range

Leptonycteris nivalis is a migratory species, with a range that includes W Texas, New Mexico, and SE Arizona (U.S. Fish and Wildlife Service, 2000), and extends south spanning Mexico, Honduras, and Guatemala (BCI, 2001).

Habitat

The Mexican long-nosed bat primarily lives at elevations ranging from 1,550 - 9,330 feet in habitats described as “desert scrub, open conifer-oak woodlands, and pine forest habitats in the Upper Sonoran and Transitional Life Zones” (U.S. Fish and Wildlife Service 2001). During the day, L. nivalis roosts in sheltered places like caves, hollow trees, and mines. However, information on roosting habitats is limited (U.S. Fish and Wildlife Service, 2000).

  • Range elevation
    516.67 to 3110 m
    1695.11 to 10203.41 ft

Physical Description

Leptonycteris nivalis is 70-90 mm long, weighing 18-30 g. Their hair coat on their back is pale brown to gray. They have three vertebrae in their tail; however, it is not visible externally. L. nivalis has a third finger that measures 105mm. Long hairs protrude from and extend past a narrow piece of skin along the inside edge of each leg called the interfemoral membrane or uropatagium. They have an elongated snout with a triangular nose leaf on the end. In order to feed on nectar, Mexican long-nosed bat have a long tongue with inward-pointing, elongated papillae at its tip (U.S. Fish and Wildlife Service, 2000). The dental formula is 2/2, 1/1, 2/3, 2/2x2 = 30 (Davis & Schmidly, 1997).

  • Average mass
    18-30 g
    oz
  • Range length
    70 to 90 mm
    2.76 to 3.54 in

Reproduction

Some studies have shown that L. nivalis may have two breeding peaks a year, one in spring and one in September. Other studies have shown that the breeding season is limited to the month of May (U.S. Fish and Wildlife Service, 2000). L. nivalis give birth to one offspring annually in Mexico in caves. Female Leptonycteris nivalis carry the offspring inflight until it can fly on its own when it is weaned, usually a couple of months after birth (Davis and Schmidly, 1997).

  • Breeding season
    May possibly September
  • Average number of offspring
    1

Lifespan/Longevity

The average life span of the Mexican long-nosed bat is approximatly 10 years (Texas Parks and Wildlife, 2001).

  • Average lifespan
    Status: wild
    10 years

Behavior

The migratory behavior exhibited by L. nivalis may be derived from the symbiotic relationship it has with Agave sp., its primary food source. Agave sp. flower once at night and then perish. The Mexican long-nosed bat's night activity and its migratory pattern matches the northward, seasonal flowering pattern of Agave. L. nivalis is a colonial species that forages for food in large flocks (U.S. Fish and Wildlife Service, 2000). The most extensively studied colony is at Emory Peak Cave, in Texas. It is a colony of juveniles with both female and male adults interdispersed (Davis & Schmidly, 1997).

Communication and Perception

Food Habits

In general Mexican long-nosed bats are nectarivores. They feed primarily on the nectar of Agave spp. Researchers have suggested that Mexican long-nosed bats physical adaptations of short ears and the presence of a triangular noseleaf are evidence that they use their sense of smell to locate Agave sp. plants rather than echolocation (Arita and Wilson, 1987). Mexican long-nosed bats feed secondarily on pollen from cactus flowers, and some berries and fruits. Leptonycteris nivalis feeds at night in flocks when Agave sp. are blooming. Its migratory patterns also match the blooming patterns of certain plants of Agave such as A. angustifolia (mezcal plant), A. salmiana (pulque plant), and A. tequilana (tequila plant) (Arita, 1991). Mexican long-nosed bats forage by hovering over the blooming Agave and by clinging to herbacious vegetation. Since L. nivalis eat a lot of nectar, their demand for water is very low to absent (New Mexico Game & Fish, 2000).

  • Plant Foods
  • fruit
  • nectar
  • pollen

Ecosystem Roles

L. nivalis has a very important role in the ecosystem; its presence directly and indirectly affects many biological interactions within its community. Many plants, like Agave, depend on the bat for the cross-pollination that maintains crucial genetic diversity within each plant species. Other species are dependent on plants pollinated by L. nivalis for their food and shelter. These include bees, moths, lizards, hummingbirds, woodpeckers, orioles, finches, sparrows, and field mice (Arita & Wilson, 1987). A decline in L. nivalis population could mean a reduction in the Agave population and many other species that rely on these plants, thereby changing the dynamics and interactions within the community. Leptonycteris nivalis has a mutualistic or symbiotic relationship with Agave, its primary food source (U.S. Fish and Wildlife Service, 2000).

Mutualist Species
  • Agave sp.

Economic Importance for Humans: Positive

Agave sp. are of great economic importance in Mexico. Fibers called henequin are produced from the leaves of certain species of Agave. These fibers are exported, and they generate a substantial amount of revenue for some regional and local economies in Mexico. Tequila, another highly exported good produced in Mexico is primarily produced from Agave tequilana. The sale of tequila in international markets also produces a large amount of revenue for the country. The reproductive success of Agave spp. relies on the Mexican long-nosed bat to pollinate and cross pollinate plants. Without the bats, Agave seed count would drop to 1/3000th of normal (Arita & Wilson, 1987). L.nivalis also produce mass quantities of guano, which can be collected and used as fertilizer (Garza, 2001).

  • Positive Impacts
  • produces fertilizer
  • pollinates crops

Economic Importance for Humans: Negative

Leptonycteris nivalis has been known to roost on attic and parking garage ceilings. Beyond the inconvenience of having a bat living in your home, long-nosed bats produce large amounts of bat excrement or guano that can sustain bacteria and insects. The breakdown process of guano also releases large amounts of ammonia, which if humans are exposed to for periods of time can cause lung deterioration (Garza, 2001).

Conservation Status

Leptonycteris nivalis was listed in 1988 as an endangered species by the US Fish and Wildlife service and by the state of Texas. In 1990, New Mexico listed L. nivalis as endangered, and in 1991 L. nivalis was listed as endangered under the Mexican Endangered Species Act. The Mexican long-nosed bat population has been steadily declining over the years due to declining number of roost sites and the increased harvesting of Agave sp. to make liquor; these harvests decreased the primary food source of the bats (U.S. Fish and Wildlife Service, 2000). In southern Mexico many L. nivalis have been mistaken for vampire bats and killed in attempts to reduce the number of that species (Texas Parks and Wildlife, 2001). Efforts of conservation focus on increasing the abundance of roost sites, protecting existing roost sites, protecting critical Agave sp., and expanding biological information including the obtainment of an accurate population estimate (U.S. Fish and Wildlife Service, 2000).

Temperate North American bats are now threatened by a fungal disease called “white-nose syndrome.” This disease has devastated eastern North American bat populations at hibernation sites since 2007. The fungus, Geomyces destructans, grows best in cold, humid conditions that are typical of many bat hibernacula. The fungus grows on, and in some cases invades, the bodies of hibernating bats and seems to result in disturbance from hibernation, causing a debilitating loss of important metabolic resources and mass deaths. Mortality rates at some hibernation sites have been as high as 90%. While there are currently no reports of Leptonycteris nivalis mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America. (Cryan, 2010; National Park Service, Wildlife Health Center, 2010)

Other Comments

To some extent, lack of information regarding basic life history for this species may be attributed to the combination of Leptonycteris nivalis with Leptonycteris curasoae in classification of these species from 1940-1962 (U.S. Fish and Wildlife Service, 2000).

Contributors

Rosie Clarke (author), University of Michigan-Ann Arbor, Kate Teeter (editor), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

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

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

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

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

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.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

internal fertilization

fertilization takes place within the female's body

keystone species

a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

native range

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

nectarivore

an animal that mainly eats nectar from flowers

nocturnal

active during the night

scrub forest

scrub forests develop in areas that experience dry seasons.

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

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Arita, H. 1991. Spatial Segregation In Long-Nosed Bats Leptonysteris nivalis and Leptonycteris curasoae In Mexico. Journal of Mammalogy, 72 (4): 706-714.

Arita, H., D. Wilson. December, 1987. Long-Nosed Bats and the Agaves: The Tequila Connection. Bat Conservation International, 5: 3-5.

Bat Conservation International (BCI), 2001. "About Our Cover Image" (On-line). Accessed September 29, 2001 at http://www.batcon.org.

Cryan, P. 2010. "White-nose syndrome threatens the survival of hibernating bats in North America" (On-line). U.S. Geological Survey, Fort Collins Science Center. Accessed September 16, 2010 at http://www.fort.usgs.gov/WNS/.

Davis, W., D. Schmidly. 19987. "Mexican Long-nosed bat" (On-line). Accessed October 10, 2001 at http://www.nsrl.ttu.edu/tmot1/leptniva.htm.

Garza, Sam, , Fort Worth Zoo. August 1, 2001. "Mexican Long-nosed Bat" (On-line). Accessed September 29, 2001 at http://whozoo.org/AnlifeSS2001/samdelag/SDLG_LongnosedBat.htm.

National Park Service, Wildlife Health Center, 2010. "White-nose syndrome" (On-line). National Park Service, Wildlife Health. Accessed September 16, 2010 at http://www.nature.nps.gov/biology/wildlifehealth/White_Nose_Syndrome.cfm.

New Mexico Game and Fish, "Biota Information System of New Mexico Bison" (On-line). Accessed October 10, 2000 at http://www.fw.vt.edu/fishex/nmex_main/species/050060.htm.

Texas Parks and Wildlife, February 11, 2001. "Endangered and Threatened" (On-line). Accessed September 29, 2001 at http://www.tpwd.state.tx.us/nature/endang/animals/lnosebat.htm.

U.S. Fish and Wildlife Service, December 14, 2000. "Mexican Long-nosed bat" (On-line). Accessed September 29, 2001 at http://bb35.tpwd.state.tx.us/nature/wild/mammals/bats/species/mex_longnose.htm.

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