Macrotus californicus
California leaf-nosed bat

The California leaf-nosed bat, the most northern member of the Phyllostomidae, lives in Northen Mexico, Baja California, southern Arizona, southern California and southern Nevada (Constantine 1998).

This species can be found in the caves and abandoned mines in deserts of South West North America. In the winter, they choose roosts that are geothermically heated (Tuttle 1998).

The Macrotus californicus has short broad wings and huge ears and eyes (Tuttle 1998). It's skull has no post orbital processes and a complete premaxillae.

During the summer, most males form separate colonies close to female groups of around 100-500 members. However, a handful of dominant males stay within the female colony and have harem groups consisting of 5-25 females and young (Tuttle 1998).

Mating takes place in the fall. For the first several months of gestation, the embryo develops extremely slowly. Development speeds up in the spring, and young are born in June. (Tuttle 1998).

Infants are born with open eyes and ears and a full coat of fur. Infants nurse for one month. While females become sexually mature their first fall, males take a full year to reach sexual maturity (Harris 1999).

These bats have year long activity and do not migrate or hibernate. Members of this species are nocturnal, generally emerging 90-120 minutes after sunset during the summer, returning to their roost approximately one hour before sunrise (Harris 1999).

M. californicus is an insectivore. It uses its unuusal hovering ability to capture insects from the ground instead of from the air. It also uses its keen sense of vision over echolocation whenever light is adequate (Bell 1986). They feed up to 1.3km from their roost (Harris 1999).

Foods eaten include: crickets, moths, beetles, and grasshoppers, cicadas and caterpillars.

M. californicus plays an important role in insect control.

M. californicus, an insectivorous bat, helps to control pest populations.

Populations of this species are definitely decreasing. Human disturbances in caves and the reestablishment of mines is driving these animals out of their homes.

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 Macrotus californicus 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)