Climatic conditions in the spring are therefore crucial, as they dictate the emergence of insects, which the bats need as an immediate source of food. The gestation period of Canadian bats can be as short as 40 days (Keen’s myotis and the long-eared bat) or be as long as 100 days (Townsend’s big-eared bat).Ĭoming out of hibernation, bats are on the hunt for food, having exhausted almost all of their fat reserves. Colder temperatures will delay the development of offspring. Gestation varies depending on the species, as well as the food availability and ambient temperature. This phenomenon is called delayed ovulation. After bats come out of hibernation in April, females ovulate and fertilizations occurs. Spring: Gestationĭuring the winter, sperm is kept viable in the female’s uterus. Bats affected by this fungus can be recognized by the presence of white spots on their wings and faces, giving the name white-nose syndrome to this “infection”. It causes bats to wake up more often than normal and thereby increases their energy expenditure. Noise, light and heat can easily disturb them (Biodôme de Montréal et Metro Toronto Zoo, 1997).įor several years now, the hibernation of bats has been disturbed by a fungus that has become widespread across many hibernacula. Entering hibernacula during the winter should be avoided to prevent bats from arousing from hibernation. A single arousal can consume fat reserves that represent the energy required for 30-60 days of hibernation. Waking up from torpor requires a large amount of energy since they must warm their body temperature from just above freezing to 36☌ in a very short amount of time. Bats will come out of torpor about once a month (every 12-30 days) to urinate and rehydrate. Bats are able to survive cold winters because of these physiological adaptations and because of fat reserves that can account for up to 35% of their weight. Some species hibernate in small groups, whereas others hibernate alone.ĭuring hibernation, the heart rate of bats decreases to about 25 beats per minute (bpm) (a normal active heart rate is 400-1000 bpm when active) and their body temperature decreases from 36☌ to 3-6☌. A desirable hibernacula for bats has a high humidity with a temperature slightly above freezing. The big brown bat will sometimes hibernate in human dwellings as well. They are usually located in crevasses, caves or abandoned mines. The roosts where bats hibernate are called hibernacula. Some, such as the red bat (Lasiurus borealis) will travel as far as Mexico and the hoary bat (Lasiurus cinereus) travels all the way to the Carribean. Winter: Hibernationīetween October and November, cave-dwelling bats begin making their way to their hibernation roosts, while migratory bats leave Canada and travel to their wintering grounds in the Central and Southern United States. The partners remain united for several minutes. To avoid losing his grip, the male bites the skin at the nape of the female’s neck. Suspended by his hind paws, the male embraces the female in his arms and climbs on her back. ![]() Mating in different species occurs after a courting ritual that involves either singing or chasing one another. The reproductive period is the best season for determining the sex of bats because male reproductive organs can be easily observed. Sadly, this behaviour could be contributing to the propagation of white-nose syndrome As a result, some scientists believe that swarming is essential for the persistence of diverse populations. This is an advantageous reproductive strategy because it increases genetic diversity. Since swarming sites can be visited by hundreds of individuals in one night, they ensure a high copulation rate. Females also spend time with their young at this time, demonstrating that swarming sites also represent places of learning for the young bats. At swarming sites, males can be observed courting females to mate with. Swarming is a unique event during the life-history of bats because it is one of the rare occasions when a large number of bats can be found in a single area. ![]() This congregation of bats is called “swarming” and this is generally when mating occurs. In the fall, just prior to hibernation, bats can be seen flying in large numbers usually near the entrances of hibernacula.
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