Lesser long-nosed bat
Leptonycteris yerbabuenae

Description: The lesser long-nosed bat is gray or yellow-brown above and reddish-brown below, with a short tail and small ears. It has a triangular shaped nose leaf, a projection of skin above the nostrils, which juts from the end of its nose. This species of bat is medium-sized and weighs less than 25 grams. It is 2.5 to 3 inches long and has a 14 inch wingspan. Juvenile lesser long-nosed bats have gray fur. These bats eat nectar, pollen, and fruit and feed exclusively on night-blooming cacti, with columnar cactus flowers and fruits and agave flowers representing its core diet.

Life History: Lesser long-nosed bats migrate seasonally from Mexico to southern Arizona and southwestern New Mexico, residing in the United States between early-April and mid-September. Such long-distance migration is rare among bats, and is found in only three other nectarivorous and two insectivorous North American bat species. Not all individuals of this species migrate, with females more likely to undertake the journey than males. Mating occurs in Mexico in the winter, and females generally give birth to one pup after migrating to the United States. Timing of mating and birth may vary geographically, with birth coinciding with peak flower availability.

Pregnant females with their recent adult progeny arrive in the United States first and form maternity colonies near columnar cacti. Adult males often occupy separate roosts forming bachelor colonies. Young are born with well-developed feet and are left at night to hang in the roost for the first several weeks while the females forage. Young begin to fly at four weeks and begin leaving the roost at six or seven weeks, when the female stops nursing. Between foraging at night both sexes will rest in temporary night roosts. Roosts can contain thousands to tens of thousands of bats. Maternity colonies begin to disband in July and August after the young are weaned.

Habitat: Lesser long-nosed bats are found in desert scrub habitat. In addition, they require appropriate day and night roosting habitat. In the United States the bats use hot, humid caves and abandoned mines as day roosts. Night roosts are found in the bats' day roosts as well as other caves, mines, rock crevices, trees and shrubs, and abandoned buildings. In Mexico, fall and winter roosts occur in tropical deciduous and thorn forests.

Distribution:

This species is found in southern Arizona and southwestern New Mexico south to western Mexico and Baja California del Sur.

Status: These bats were listed as endangered in 1988 under the Endangered Species Act. Causes for the decline include maternity roost disturbance and habitat loss due to development, invasive annual grasses, and changes in fire regimes affecting both the bat and its food sources. The harvest of agave for tequila production is increasing and this activity also threatens the species. Other researchers have suggested that lesser long-nosed bats may not be declining and may have even benefited from the availability of mines as roost sites. However, much remains to be learned about the status of this species.

Resources:

Animal Fact Sheets: Lesser Long-nosed Bat (Arizona-Sonora Desert Museum)

Coronado National Memorial: Lesser long-nosed bat (United States Department of the Interior, National Park Service)

Lesser Long-Nosed Bat Recovery Plan (United States Fish and Wildlife Service)

Lesser Long-Nosed Bat (Leptonycteris curasoae yerbabuenae) (Center for Biological Diversity)