Myotis lucifugus

Status

Three species of bats have been confirmed to date on the island of Newfoundland and one in Labrador. These are the Little Brown Bat (Myotis lucifugus), the Northern Long-eared Bat [Myotis keenii (septentrionalis)], and the Hoary Bat (Lasiurus cinereus). The Little Brown Bat is the most common on the island and is the only species known to live in Labrador. It can be a challenge to locate, observe, identify and census bats because of their nocturnal and secretive nature. When you can find them, they are likely to be flying around, zigzagging and diving in the dark of the night.

There are special aids that help locate the bats. An electronic instrument, called the bat detector, enables humans to hear sound pulses emitted by the hunting bats. Bat researchers with experience using bat detectors can learn to identify many species of bats. Bats use certain frequencies, and every species has its own characteristic pattern, similar to the way each bird species has its own individual song.

Another monitoring aid is the Tuttle trap (it looks like a bed spring). This is a trap that allows researchers to capture bats without harming them. The captured bats are identified, banded, counted, and released unharmed. More study is needed so that we may learn more about this fascinating creature.

Habitat

In Newfoundland little brown bats are found virtually anywhere there are trees, buildings, or caves. During the year the bats will use two different types of roosts (places to rest or sleep). In the summer they will roost in buildings or trees. In many parks bats can be seen especially around your campfire. In winter, the bats need to find frost-free places in which to hibernate, such as caves, mineshafts, cellars, tunnels, or unoccupied buildings.

Food

Little brown bats feed on insects such as moths, beetles, mosquitoes, and flies. A single little brown bat can catch 600 mosquitoes in just one hour. Bats hunt for about two hours after sunset and two more hours just before sunrise. Between hunts, the bats rest in roosts – often crevices – where they form tight clusters. During the summer months, the bats consume about half their weight in insects each night. This enables them to put on the body fat needed to survive months of hibernation.

Predators/Threats

One great threat to bats is the loss or disturbance of their habitat. Traditionally, bats have roosted in trees and caves. They have adapted to living in buildings because fewer and fewer trees and caves are available to them.

Bats and people are not always compatible when it comes to sharing living space. Harmful chemicals have been used in trying to eliminate bats from attics but this can be harmful to humans as well. Local wildlife officials can advise and help with removing bats without harming them, you or your property.

When bats are disturbed during their winter hibernation, they use up vital energy reserves. The food supply of the little brown bat consists of insects which are available only in the spring and summer months. Without being able to replenish the lost energy, the bats could die.

Some people harass or even kill bats out of fear and ignorance. They may think that bats are diseased and dirty. While bats are not as dangerous as portrayed in the past, they are wild animals and therefore should be treated with respect.

Nearly 40% of North American bat species are threatened or endangered. Around the world, many more bat populations are declining at alarming rates. Four Canadian bat species have been listed as vulnerable by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC); namely, Fringed Myotis (Myotis thysanodes), Keen’s Long-eared (Myotis keenii), Pallid (Antrozous pallidus) and Spotted (Euderma maculatum).

The loss of food supply is another threat to the bat population. The disruption of natural habitat reduces the numbers and varieties of insects that the little brown bat feeds on. Pollution and pesticides can also reduce the food supply for bats, and pesticides can potentially poison the bats themselves.

The little brown bats have some natural predators such as hawks and owls that can harm them as well. Even trout will prey on hunting bats while they are flying low over the water! Small carnivores (meat eaters), such as cats, rats, weasels, mink and squirrels, can enter the bats’ roosting areas and prey upon the bats.

Lifespan

Bats often live for more than 10 years. Other equally small mammals such as shrews have a very short life span of a year or two. Two little brown bats were recaptured 29 and 30 years after banding! The thirty-year old bat did not appear fragile or have worn teeth, the tell-tale sign of being old.

Appearance

The little brown bat’s fur colour can range from pale tan to reddish or dark brown, and its ears and wings are dark brown to black. The little brown bat reaches a maximum length from nose to tail-tip of approximately 9 centmetres. An adult weighs only 8 grams and can crawl through an opening about 1 centimetre wide. The wingspan is about 22-27 cm. The wings are membranes of skin, supported by forearms and elongated fingers that have evolved to form the support structure. The wings extend down the sides of the body to the legs. Besides flying, bats use their wings for crawling, catching prey and grooming. Little brown bats also have a membrane between their hind legs (interfemoral) which helps them to maneuver in flight and to scoop up insects. Pregnant females also catch their newborns in this membrane.

Breeding Biology

In Newfoundland, in early April, the pregnant females begin their spring migration to summer roosting sites where they establish maternity colonies. The males either roost alone or form small separate colonies by themselves. The gestation period is two months, or so, depending on available food and climate. Most little brown bats produce only one young or pup a year, usually in June or July. A pup may weigh as much as 30% of the mother’s weight; that’s like a 120-pound woman giving birth to a 36-pound infant. For the first three or four days of its life the pup hangs on to its mother, even when she is searching for food. The young bats fly on their own in about three weeks.

Average weight/measurements

The little brown bat reaches a maximum length from nose to tail-tip of approximately 9 centmetres. An adult weighs only 8 grams and can crawl through an opening about 1 centimetre wide. The wingspan is about 22-27 cm.

Notes

Bats have long been associated with vampires, Halloween, and things that go bump in the night. Most fear of bats is based not on fact but on myths, legends, and superstition. Fear of bats subsides with knowledge and accurate information.

Myth: Bats are birds.

Fact: Bats are not birds but flying mammals.

Myth: Bats are blind.

Fact: Bats can see quite well.

Myth: Bats always get tangled in human hair.

Fact: Bats do not become entangled in human hair deliberately, though they may dive for flying insects near a person’s head.

Myth: All bats bite and carry rabies and diseases.

Fact: Not all bats bite and carry diseases. Bats seldom transmit disease to other animals or humans, but bats are wild animals and should not be disturbed, in case they are carrying certain diseases.

Myth: All bats drink blood.

Fact: The bats of Newfoundland and Labrador do not feed on the blood of people or animals. The little brown bat is a harmless insect eater. With the exception of the tropical Vampire bat (not found in Canada), most bats feed on insects or fruit. Soon an anticoagulant (a substance that hinders the clotting of blood) found in the saliva of the vampire bat may be used to treat heart patients.