Leptonycteris nivalis

Mexican Long-nosed Bat

FWS Focus

Overview

Characteristics
Overview

The Mexican long-nosed bat (Leptonycteris nivalis) is a nectivorous species of bat, ranging from the southwestern United States to Central Mexico, and mainly found in desert and pine-oak forest habitats. The species engages in an annual long-distance migration that coincides with flowering phenology of food resources, mainly agaves and columnar cacti. The loss of food resources due to conversion of foraging habitat to agriculture and ranching, in addition to the disturbance by humans, is thought to have contributed to the decline of the population sizes of this species by at least 50% in the last 20-30 years.

Scientific Name

Leptonycteris nivalis
Common Name
Mexican Long-nosed Bat
Greater Long-nosed Bat
FWS Category
Mammals
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

The Mexican long-nosed bat is a large bat in comparison with most bat species in the U.S.

Measurements

Length: 2.75 to 3.75 in (6.99 to 7.62 cm)

Color & Pattern

Mexican long-nosed bats are a dark gray to "sooty" brown color. The Mexican long-nosed bat is grayish brown on upper parts and paler on the shoulders and under parts.

Characteristic category

Habitat

Characteristics
Habitat

Mexican long-nosed bats typically roost in caves, although they have been found in mine tunnels, found at elevations of 1,000 to 2,300 m, typically in pine-oak habitats. The species requires roosts (caves, mines, crevices) with appropriate temperatures (around 18 °C) and humidity, with limited human disturbance and limited access to predators. Appropriate roosts are required in summer and winter areas, and along the migration pathway, however much is unknown about the migratory paths of this species throughout the year.

Cave or Karst

A natural chamber or series of chambers in the earth or in the side of a hill or cliff. An irregular limestone region with sinkholes, underground streams and caverns.

Characteristic category

Food

Characteristics
Food

While Mexican long-nosed bats can feed on more than 50 species of plants, they are thought to specialize feeding on species from the families Agavaceae and Convolvulaceae, specifically those in the genus Agave and Ipomoea. The Mexican long-nosed bat requires healthy populations of flowering plants included in its diet (mainly Agaves and cacti), near roosting sites and along migratory routes. Adequate foraging resources within 50 km of roosting sites are considered crucial, especially for maternity colonies.

 

Characteristic category

Behavior

Characteristics
Behavior

 

Characteristic category

Life Cycle

Characteristics
Life Span

The life span of the Mexican long-nosed bat is approximately 10-12 years.

Reproduction

L. nivalis has a monoestrous reproductive pattern, mating and giving birth only once a year. L. nivalis gathers in Central Mexico during fall-winter to mate. Cueva del Diablo (Tepoztlán, Morelos) is the only known mating roost where males and females concentrate in the winter range and likely is where most mating occurs. Females and males have been reported in other roosts in Central Mexico during winter but groups of L. nivalis in these roosts are only a few dozen.

During the mating season, a few groups of multiple males and females are formed and these groups move between chambers inside the cave. Studies of mating behavior in Cueva del Diablo have not reported any type of female guarding, group, or harem defense by the males, nor any type of courting behavior by the males. Females, however, have been observed defending the male from other females while copulating, suggesting some sort of mate selection behavior by the females.

Following mating, females tend to make the migration northward, while males tend to remain in the southern part of the distribution.

Geography

Characteristics
Range

The Mexican long-nosed bat has a geographic range that covers four regions: central Mexico, eastern Mexico, northeastern Mexico, and the southwestern United States.

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