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The eastern small-footed bat (''Myotis leibii'') is a
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
vesper bat Vespertilionidae is a family of microbats, of the order Chiroptera, flying, insect-eating mammals variously described as the common, vesper, or simple nosed bats. The vespertilionid family is the most diverse and widely distributed of bat familie ...
. It can be found in southern
Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
and
Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
in
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
and in mountainous portions of the eastern United States from New England to northern Georgia, and westward to northern Arkansas. It is among the smallest bats in eastern North America and is known for its small feet and black face-mask. Until recently, all North American small-footed Myotis were considered to be "''Myotis leibii''". The western population is now considered to be a separate species, ''Myotis ciliolabrum''. The Eastern small-footed bat is rare throughout its range, although the species may be locally abundant where suitable habitat exists. Studies suggest
white-nose syndrome White-nose syndrome (WNS) is a fungal disease in North American bats which has resulted in the dramatic decrease of the bat population in the United States and Canada, reportedly killing millions as of 2018. The condition is named for a distincti ...
has caused declines in their populations. However, most occurrences of this species have only been counted within the past decade or two and are not revisited regularly, making their population status difficult to assess. Additionally, most bat populations in the Eastern U.S. have been monitored using surveys conducted in caves and mines in the winter, but Eastern small-footed bats hibernate in places that make them unlikely to be encountered during these surveys. Perhaps as a result, the numbers of Eastern small-footed bats counted in winter tend to be low and they are relatively variable compared to other species of bats. Many biologists believe the species is stable, having declined little in recent times, but that it is vulnerable due to its relatively restricted geographic range and habitat needs.


Description

The eastern small footed bat is between 65 and 95 millimeters in length, has a wingspan of 210 to 250 millimeters, and weighs between 4 and 8 grams (with 4.0-5.25 grams being typical). The bat got its name from its abnormally small hind feet, which are only 7 to 8 millimeters long. A defining characteristic of this bat is its appearance of having a dark facial "mask", created by nearly black ears and muzzle. In most individuals, the ears, wings and
interfemoral membrane The patagium (plural: patagia) is a membranous body part that assists an animal in obtaining lift when gliding or flight. The structure is found in extant and extinct groups of flying and gliding animals including bats, birds, some dromaeosaurs ...
, (the membrane between the legs and tail) are dark and contrast starkly with the lighter colored fur on the rest of the body. The fur on the dorsal side of their body is dark at the roots, and fades to a light brown at the tips, which gives the bats a signature shiny, chestnut-brown appearance. Like all bats, the eastern small-footed bat has a
patagium The patagium (plural: patagia) is a membranous body part that assists an animal in obtaining lift when gliding or flight. The structure is found in extant and extinct groups of flying and gliding animals including bats, birds, some dromaeosaurs ...
that connects the body to the forelimbs and tail, aiding in flight. Their head is relatively flat and short, with a forehead that slopes gradually away from the
rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...
, a feature that is unique to other individuals in the
Myotis The mouse-eared bats or myotises are a diverse and widespread genus (''Myotis'') of bats within the family Vespertilionidae. The noun "''myotis''" itself is a New Latin construction, from the Greek "''muós'' (meaning "mouse") and "''oûs''" (mea ...
species. They have erect ears, which are broad at the base and a short flat nose. Like other Myotis, they have a pointed tragus. They also have a distinctly keeled
calcar The calcar, also known as the calcaneum, is the name given to a spur of cartilage arising from inner side of ankle and running along part of outer interfemoral membrane in bats, as well as to a similar spur on the legs of some arthropods. The ...
(cartilagenous rod on the hind legs to support the interfemoral membrane). Their forearm length, which is less than 34 mm, can be used to distinguish them from all other Myotis in Eastern North America. Tail is between 25-45 millimeters in length and protrudes past their interfemoral membrane, and they have a dental formula of 2/3, 1/1, 3/3, 3/3. Eastern small-footed bats are most likely to be confused with the
little brown bat The little brown bat or little brown myotis (''Myotis lucifugus'') is an endangered species of mouse-eared microbat found in North America. It has a small body size and glossy brown fur. It is similar in appearance to several other mouse-ea ...
(''Myotis lucifugus''), especially in individuals where the face-mask is less apparent; however, forearm size less than 34mm and presence of a keeled calcar are considered diagnostic.


Range and distribution

The range of this species includes Northern
Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...
and southern
Missouri Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...
, East to the
Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...
and Ohio River Basin, South into northern Georgia, and North into
New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
, southern
Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
and
Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
. Distribution is spotty within their entire range, and they are considered to be uncommon. These bats are mostly associated with rock formations in
deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...
or
coniferous Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant ...
forests. Most observations have been from mountainous areas from 240–1125 meters in elevation, where exposed rock formations are more common. However, the species has also been observed at lower elevation rocky sites. During the spring, summer, and autumn they predominantly roost at emergent rock-outcrops such as cliffs, bluffs, shale barrens, and talus slopes, but also man-made structures, including buildings, joints between segments of cement guard rails, turnpike tunnels, road-cuts, and rip-rap covered dams. The largest populations of ''Myotis leibii'' have been found in New York, Pennsylvania, West Virginia and Virginia. (red list) The total count of individuals across all known hibernacula is only 3,000, with roughly 60% of the total number from just two sites in New York.Erdle Y., S. Hobson (2001). Current status and conservation strategy for the eastern small footed Myotis (''Myotis leibii''), Virginia Department of Conservation and Recreation, National Heritage Technical Report: #00-19. Unfortunately, 90% of their habitat is on private land, which makes it difficult to protect them.


Diet

Eastern small-footed bats are believed to feed primarily on flying insects such as
beetles Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
,
moths Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...
, and
flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...
and are capable of filling their stomachs within an hour of eating.Best, T., J.S. Altenback., J.M. Harvey Eastern small-footed bat. The Tennessee Bat Working Group. They are nighttime foragers and usually forage in and along wooded areas at and below canopy height, over streams and ponds, and along cliffs. Moths compose nearly half of their diet, and they forage primarily on soft-bodied prey. It is believed that the avoidance of hard prey is due to their small, delicate skulls. The food habits of eastern small-footed bats are similar to those of the closely related
California Myotis The California myotis (''Myotis californicus'') is a species of vesper bat. It is found in British Columbia in Canada, Guatemala, Mexico, and in the western United States, including California. Description The California myotis is a small (70– ...
(''M. californicus'') and
western small-footed bat The western small-footed bat (''Myotis ciliolabrum''), also known as the western small-footed myotis, is a species of vesper bat native to North America. Description Western small-footed bats are relatively small bats, having a total length of , ...
(''M. ciliolabrum''), as well as other North American Myotis (e.g.,
little brown bat The little brown bat or little brown myotis (''Myotis lucifugus'') is an endangered species of mouse-eared microbat found in North America. It has a small body size and glossy brown fur. It is similar in appearance to several other mouse-ea ...
, (''M. lucifugus''), and
northern bat The northern bat (''Eptesicus nilssonii'') is the most abundant species of bat in northern Eurasia occurring from England to Hokkaidō and south to northern India. Description The northern bat is dark brown or black with some gold touched at th ...
, (''M. septentrionalis'').


Hibernation

The eastern small-footed bat is most often detected during
hibernation Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
, and has been counted at approximately 125 caves and mines.Arryo-Cabrales, J., T.A. Castaneda (2008). ''Myotis leibii'' in IUCN red list. IUCN Red List of Threatened Species. 13.1. They are one of the last species to enter hibernation in the fall and the first to leave in the spring, with a hibernation period lasting from late November to early April. They have been found in relatively cold caves and mines and can tolerate lower temperatures than other bat species (Whitaker and Hamilton 1998). Unlike most other bat species, they often hibernate in caves and mines that are relatively short (150m) and they are most often found hibernating near the entrance where temperatures sometimes dip below zero and the humidity is low (Barbour and Davis 1969; Merritt 1987; Harvey 1992). Such locations may put them at a greater risk of
white nose syndrome White-nose syndrome (WNS) is a fungal disease in North American bats which has resulted in the dramatic decrease of the bat population in the United States and Canada, reportedly killing millions as of 2018. The condition is named for a distincti ...
, although the species appears to have been less impacted by the disease than some others. Estimates from winter cave and mine surveys suggest the disease caused a 12% decrease in their overall population between 2006 and 2011, which is lower mortality than other species of Myotis experienced at the same sites.Salazar, K., M, Matteson (2010). Petition to list the Eastern small-footed bat ''Myotis leibii'' and Northern Long eastern bat ''Myotis septentrionais'' as threatened of endangered under the Endangered Species Act. The Center for Biological Diversity. Other aspects of their biology make them difficult to count, but also probably offer some protection from WNS. For example, they tend to hibernate individually or in groups of less than 50, and often in small crevices. Bat biologists have speculated that the species also may hibernate outside of caves and mines. Observations of eastern small-footed bats in western Virginia roosting in crevices along sandstone cliff faces in winter support this idea.


Spring and summer roosting

There is little published information about the spring and summer roosting locations of eastern small-footed bats. The first study into the summer roosting habits was only done in 2011 so information is scarce. This study discovered that these bats most commonly use ground level rock roosts in talus slopes, rock fields and vertical cliff faces for their summer roosts. On average they change their roosts every 1.1 days, males travel about 41 meters between consecutive roosts and females around 67 meters. They also found that females roosting sites were closer to ephemeral water sources than male's roosts. Females who have young require roost sites that receive a lot of sunlight in order to keep the pups warm while the mother is away from the roost. Summer roosting habitats were previously considered difficult to find, but several recent studies have shown that the species is relatively easy to locate if survey efforts are focused near appropriate rocky habitats.


Mating and reproduction

As with many other species of bats, the eastern small-footed bat usually has only one offspring a year, although a few instances of twins have been noted. This
k-selected In ecology, ''r''/''K'' selection theory relates to the selection of combinations of traits in an organism that trade off between quantity and quality of offspring. The focus on either an increased quantity of offspring at the expense of indivi ...
reproductive strategy means that their populations are not capable of withstanding high mortality rates, making them particularly vulnerable to sudden population declines. Mating most often occurs in autumn and the female stores the male's sperm throughout hibernation in the winter. Fertilization occurs in the spring once the females are active again, and gestation occurs between 50–60 days with young being born in late May and early June. Mating has also been noted to occur throughout the hibernation period, if individuals are awake. During the time of breeding, large number of bats come together in a behavior commonly known as "swarming." All bats of this genus are polyandrous, meaning they mate with multiple partners throughout the mating period. This mating behavior allows them to increase the likelihood of
copulation Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...
, and therefore increase their reproductive success. Male bats initiate copulation by mounting the female and tilting her hear back 90 degrees. The male then secures his position by biting and pulling back on the hairs at the base of the female's skull. The male then uses his thumbs to further stabilize his position and enters the female under her interfemoral membrane. Both individuals have been noted to be very quiet during copulation. Once the process is over the male dismounts the female and flies away to find another mate. Newborn bats (called "pups") weight 20–35% of their mother's body weight and are completely dependent on their mother. The young's large body size is believed to lead to high-energy expenditure from the mother, which is what limits her to only having one offspring a year. Adult males and females may use the same rock outcrops, but as is typical for other bats in the genus, the sexes typically roost separately from one another. In Virginia, both sexes appear to roost alone or occasionally in pairs, except females begin to congregate into maternity groups around the time pups are born and likely maintain these "maternity colonies" until pups are weaned. Size of maternity colonies is not well studied, but they appear to form smaller groups than other bats in the genus.


Threats

The main threat to this species is habitat disturbance, both natural and human caused. They also likely are under threat from white-nose syndrome, pollution (especially water pollution) and human disturbance during hibernation. Very low levels of light, noise and heat are sufficient to wake hibernating bats. Once awake bats begin to expend energy and deplete critical fat reserves needed to survive winter. If disturbances within hibernacula are repeated, bats (especially juveniles) are likely to die. This phenomenon was well documented in other species of bats in eastern North America, such as the
Indiana bat The Indiana bat (''Myotis sodalis'') is a medium-sized mouse-eared bat native to North America. It lives primarily in Southern and Midwestern U.S. states and is listed as an endangered species. The Indiana bat is grey, black, or chestnut in colo ...
(''Myotis sodalis'') and gray bat (''Myotis grisescens''). White-nose syndrome is a fungal infection that attacks bats while they hibernate. In the first 6 years following the discovery of WNS, 7 million bats of 6 different species were estimated to have been killed by the disease. Early estimates of impacts from white-nose syndrome based on bats counted in hibernacula suggested a 12 percent decline in eastern small-footed bat populations. However, changes in capture rates during summer, in West Virginia and New Hampshire, suggested declines from WNS may have been more severe (68-84%) in some regions. Due to their dependency on exposed and predominantly non-forested rock outcrops for roosting sites, they may be at risk from "natural" processes such as forest encroachment and establishment of more mesic forest types due to suppression of forest fires. Likewise, the species is likely threatened a host of human activities that impact rocky habitats or the surrounding areas where eastern small-footed bats forage, such as: mining, quarrying, oil and gas drilling and other forms of mineral extraction, logging, highway construction, wind energy and other forms of agricultural, industrial and residential development. However, it is also likely that some of the above activities have created roosting sites by providing exposed rock faces.


Conservation

The eastern small-footed bat is listed as
endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...
by the
IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
. Many states in the US in which the bat resides have begun listing it as threatened, and have begun conservation efforts in order to improve its numbers. In Canada, eastern small-footed bats are considered endangered in Ontario, and "threatened or vulnerable" in Quebec. The species is not protected under the US Endangered Species Act, but was a former C2 candidate for listing prior to the abolishment of that category by the U.S. Fish and Wildlife service in 1996.Heoways. H., F.J. Brenner (1985). Species of Special Concern in Pennsylvania. Carnegie Museum of Natural History. Some states (e.g. Pennsylvania) have given the species legal protection while others have recognized its apparently low numbers and consider the eastern small-footed bat a species of concern. In the report Species of Special Concern in Pennsylvania, the Pennsylvania Biological Survey assigned ''Myotis leibii'' the status of "threatened". Other states, such as Virginia, are currently working to get the eastern small-footed Myotis legal protection. Despite these efforts not many conservation projects have been initiated to help the species. Due to their strange hibernation patterns, and the lack of information regarding their spring and summer roosting sites, meaningful conservation efforts are very difficult. The species will not usually use bat boxes like many other bat species, so construction of bat boxes is not an appropriate action to mitigate against habitat disturbance issues. However, the species is known to roost in man-made rocky habitats such as road cuts and rip-rap embankments, suggesting it should be possible to create roost sites for conservation purposes.


Longevity

The eastern small-footed bat has been recorded living up to the age of 12 years.


See also

*
Bats of Canada There are eighteen indigenous species of bats in Canada, which are found in many parts of the country. They are insectivores, and are prey to falcons, hawks, owls, snakes, cats, and raccoons.Health Canada Species The little brown bat is the mos ...


References

{{Taxonbar, from=Q1832366 Mouse-eared bats Bats of Canada Bats of the United States Fauna of the Eastern United States Cave mammals Mammals described in 1842 Taxonomy articles created by Polbot