Townsend's big-eared bat. Photo courtesy of Sharon Laughlin
From horror movies to health warnings, societal attitudes about bats are typically negative. Many people view bats as being ugly, scary, nasty little creatures who are harmful blood-sucking pests. It is this type of public attitude that has contributed to the general decline of bat populations around the world, and to the fact that many of the bat species in BC are listed as vulnerable or threatened (red- and blue-listed). As people continue to exterminate bats from their houses, actively kill bats when they come across them, or inadvertently destroy bat roost sites, bats as a whole will remain threatened.
Here are some of the real facts about bats:
- Bats are not rodents but rather belong to their own group of mammals or “Order” called Chiroptera which means “hand-wing”. The wing of a bat is two layers of skin and the bones look like a human hand with elongated fingers. In fact, bats are far more closely related to primates (such as monkeys and humans) than they are to rodents.
- Bats eat huge amounts of flying insects, sometimes more than their own weight in insects per night. That’s like a 150 lb person eating 600 “quarter-pounder” burgers in one day! Many of the insects that bats eat are likely to be mosquitoes.
- Different groups of bats eat different things. There are groups of bats that eat fruit, nectar, insects, mammals, fish, or blood. Only three species of bats in the world eat blood and these are the vampire bats of Central and South America. All bats in Canada eat nothing but insects (and other arthropods) and in most cases, only flying insects.
- The saliva of vampire bats contains an anti-coagulant that allows the blood to keep flowing after a bite so that the bat can lap up the blood. This chemical is being used as a treatment for strokes because it can help dissolve blood clots in the brain. There is a drug developed called “draculin”.
- Bats are not blind. They have eyes and can see, likely better than we can under dimly lit conditions. Some bats (flying foxes found in the old world) navigate using vision alone and appear to be able to see even better than owls!
- Bats in Canada navigate and find prey mostly using echolocation. Bats emit regular calls (at the intensity of screams) and then listen to the echo of their voice. By the sound and timing of the echo, they can determine the range, the size and type of objects in front of them, if they are flying, and how fast they are moving. It is such an amazing system that the US Navy studies bats to improve human-developed sonar systems.
- There are 16 species of bats in BC (17 if you count the one record of a Big Free-tailed Bat that washed up in 1938 in New Westminster) and half of them are considered vulnerable or threatened.
- Bats in Canada either hibernate or migrate in winter. Little is known about bat hibernation sites, especially in western Canada. Bats are extremely sensitive to disturbance when they are hibernating and should be left alone.
- Bats expend a huge amount of energy to fly. As a result, they try to save energy when they can. They regularly use a system called torpor where they lower their heart rate, metabolism and body temperature and go into a deep sleep-like condition. It is like a mini-hibernation bout. They do this periodically through the night and during the day depending on local conditions.
For more information about bats, check out Bat Conservation International.