This species was thought to be a subspecies of M. evotis until 1969, when it was found that this bat occurred with M. evotis in New Mexico. Researchers concluded that the two could not be conspecific.
Although communication patterns have not been reported, we can assume that this species resembles other members of its genus. Myotis auriculus probably uses some combination of tactile communication (which is especially important in the roosts, where they are in close proximity with conspecifics), and vocalizations in the audible spectrum. Although visual signals may be used, bats are not known for their keen eyesight, and other signals may be more important. Scent cues are probably important, especially in identifying young in the maternity roost. Myotis auriculus can perceive ultrasonic signals, and uses these to locate food. However, there is no evidence that such signals are used in communication in this species.
Communication Channels: visual ; tactile ; acoustic ; chemical
Perception Channels: visual ; tactile ; ultrasound ; echolocation ; chemical
Populations appear to be stable and no conservation efforts are underway.
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 Myotis auriculus mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America.
CITES: no special status
IUCN Red List of Threatened Species: least concern
Bats are a common known carrier or rabies, but southwesten bats are not particularly know for carrying rabies.
Negative Impacts: causes or carries domestic animal disease
Myotis auriculus consumes massive quantites of insects nightly. This species therefore assists humans by controlling populations of pesky moths.
Positive Impacts: controls pest population
Due to their high-energy requirements and subsequently incredible appetites, insectivorous bats may have a substantial impact on insect populations, insect activity, and a variety of insect-related ecological processes such as herbivory, pollination and disease transmission.
Southwestern bats are insectivorous. Their primary food is moths with wingspans ranging between 3 and 4 cm. Males eat significantly more of these than do females. This bat is known to glean its prey with from buildings and tree trunks. These bats may briefly land on the substrate to pick the insect off the surface. Like most microchiropterans, southwestern bats find their insect prey through echolocation.
Water is also very important to insectivorous bats because of the high proportion of protein in their diet, and because of their high rates of evaporative water loss. These bats are usually found in close proximity to some source of water.
Animal Foods: insects
Primary Diet: carnivore (Insectivore )
Myotis auriculus is found throughout Mexico from Veracruz, Distrito Federal, and Jalisco, northward into New Mexico and Arizona. In the United States, the range of the species is restricted to southwestern New Mexico and southeastern Arizona. The winter range of these animals is unknown. It is thought that migration may result in selection of different habitats during different seasons.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
These bats usually found in arid woodlands and desert scrub. They can be found in a variety of habitat types, from mesquite and chaparral forest to oak forests and pinon-juniper habitats. M. auriculis is also found in sycamore, rabbitbrush, cottonwood, oak savanna, oak woodland, and coniferous forest. It seems to reach its greatest abundance in areas of extensive rocky cliffs where some water is available. No day roosts are known but night roosts include buildings, mines, and caves. These bats are usually found at an elevation of 366 to 2,227 m.
Range elevation: 366 to 2,227 m.
Habitat Regions: temperate ; tropical
Terrestrial Biomes: chaparral ; forest ; scrub forest
Life span is at least 3 years.
Typical lifespan
Status: wild: 3 (low) years.
Average lifespan
Status: wild: 3 years.
Myotis auriculus is also known as the southwestern bat. The species has brownish fur that is not glossy. It also has long, brownish ears (20 to 22 mm.) and a narrow pointed tragus. The bat has a calcar without a keel and a wingspan of about 270 mm. Myotis auriculus also has a distinct sagittal crest and an inflated skull. These bats weigh between 5 and 8 g. Myotis auriculus is easily identified from Myotis evotis and Myotis thysanodes with which they are sympatric in Arizona, because their flight membranes are brown, and lack a fringe of hairs on the posterior margin of the interfemoral membrane.
Range mass: 5 to 8 g.
Average wingspan: 270 mm.
Other Physical Features: endothermic ; bilateral symmetry
It is unknown what predators this bat may be faced with.
The mating system of this little-studied animal has not been reported.
What is known wih certainty about reproduction in M. auriculus is limited. Usually a single young is born measuring from 12 to 18 mm. Young are usually born in June or early July, although birthing season is later in the southern portion of the species' range.
Beyond that, we must speculate on the reproductive biology of M. auriculus. Like other long-eared bats in the genus Myotis, it is likely that this species mates in the autumn when the bats enter their hibernaculum. In their close relatives, ovulation and fertilization do not occur until the following spring, and it is likely that M. auriculus is similar.
Breeding interval: These animals breed once annually.
Breeding season: Although not known with certainty, it is very probably that these bats breed in the autumn.
Range number of offspring: 1 to 1.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous ; sperm-storing ; delayed fertilization
Parental investment for this species has not been described. However, in most of the genus, females care for their young in maternity roosts. Females provide the young with milk, grooming, and protection until weaning. The role played by the father int he parental care of this species is unknown.
Parental Investment: no parental involvement; altricial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
