Celebrating Bat Appreciation Day, April 17, 2020
Yes, bats are definitely cool. Here are three reasons why:
1. They can fly. Bats are mammals that belong to the order Chiroptera (from the Greek cheir – “hand” and pteron -“wing”). The forelimbs of bats form webbed wings, making them the only mammals naturally capable of true and sustained flight.
2. They have a highly developed echolocation system that allows them to navigate and hunt fast-flying insects in total darkness. Basically, the bat emits beep-like sounds into its path, then collects and analyzes the echoes that come bouncing back. Using sound alone, bats can ‘see’ everything but color and detect obstacles as fine as a human hair. Nonetheless, bats can see as well as just about any other mammal.
3. They are able to regulate their body temperatures, which allow bats to lower their internal temperatures and become inactive (torpid) during cold weather and conserve the energy demands of maintaining a high body temperature.
Other Cool Things About Bats
Bats are the second-largest group of mammals in the world, the largest being rodents. One genus of bats, Myotis, which we have several representatives on Mayne Island, is more broadly distributed than any other terrestrial mammal genus. Other than Antarctica, Myotis bats can be found on every continent!
In many languages, the word for “bat” is similar with the word for “mouse”. For example, in German “Fledermaus” means “flutter” and “mouse”. (Bats however are not even closely related to mice.) In SENCOTIN, the language of the WSANEC people, bats are called SLEL,BEL,AXEN – “flaps extended arm.”
Most bat moms give birth to a single pup at a time, for good reason. Baby bats can weigh up to one-third of their mother’s body weight.
Insectivorous bats are predators of night-flying insects, and many agricultural and human pests are part of their diet. Pregnant or nursing mothers of some bat species will consume up to their body weight in insects each night. For instance, a study on the Little Brown Bat found that it ate up to 600 mosquitoes per hour. They also eat their food very fast. A Big Brown Bat eats an insect every three seconds which means it must hunt, capture and chew it within that time.
Closer to home
There are 16 bat species found in BC, the highest diversity in Canada, and all are insect eaters with around eight (the Conservancy has confirmed 5) representatives possible on Mayne Island. Many of our bats hibernate or do short migrations to hibernate and April is the month they begin to emerge.
Some local cool information about our local bats
Bats of our area have highly variable flight speeds ranging from 7 to 36 kilometers per hour, beating their wings at between 10 and 20 times per second. This depends on the size and wing length—short wings slower flight and long wings faster flight.
Mayne Island bats’ sound pulses are mostly above our ability to hear them. The highest frequency that can be heard by a human is 20 kilohertz; bats emit pulses ranging from 20 to 120 kilohertz. Many species of bats have unique sound signatures that allow us to identify them by recording sonograms of their calls. As well, individual bats vary their sound frequencies based on what they are doing. Recordings of the call frequencies during pursuit of prey, navigating along forest or cliff edges and straight flight show distinct differences.
We suspect that most of the Mayne Island bat species remain here in hibernation using tree snags, rock fissures and caves or buildings that provide the right conditions of constant cool temperature and humidity. (The Silver-haired Bat uses tree roosts during summer so likely migrates further south to hibernate.) The key to their survival at these times is their ability to lower their body temperature from a normal of 40C to below 5C while in torpor. They also lower their heart rate: the the Little Brown Myotis reduces its heart rate from 100-200 beats per minute down to five. Incredibly, when Spring arrives the bat can raise its core body temperature from 5 to 40C in about 30 minutes without external heat.
Threats to Bats’ Survival
One of the greatest threats to bats’ survival is White Nose Syndrome, a fungal disease that has decimated over seven million bats through the eastern United States and parts of eastern Canada. The presence of the syndrome has now been reported in Washington State so there is a heightened urgency to understand population abundance before the disease travels across western North America. As well, the sometimes, specialized habitats required by bats for their lifecycles are generally being lost by clearing, development, fragmentation and conversion to other uses.
What to Do?
Now that you too are struck by the wonder of bats, you are probably asking about what you can do to ensure they remain part of Mayne Island’s landscape. Read on.
Bat conservation is particularly compelling because it impacts us all. Bats are everywhere, interacting daily with the same fields, forests, and waterways that we do. Likewise, their role in maintaining the health of local ecosystems and human economies is bigger than you may realize. Bats flourish in stable ecosystems. In this way, they act as an indicator of a healthy environment
Ensuring bat survival means protecting roosts and feeding areas for all bats. Roosts such as large snags, structures, caves and rock fissures are perfect locations for bats to roost in during the day. Open water areas, wetlands, waterways, and forest edges are key feeding habitats for bat species. Where natural or building roosts are in short supply or the roosts must be moved, the installation of bat boxes, in appropriate habitats, can provide ideal spots for bats to safely rest and feed. The Mayne Island Conservancy program’s primary goals are to locate the natural roosts wherever they exist and to work with the landowners on their long-term conservation. The use and installation of bat boxes are a secondary goal. It is critical that we understand where these bats are located. By knowing exactly where they exist, we can then work towards ensuring that those areas are protected or that bat boxes are installed to substitute for changing conditions.
If you see dead bats on your property, do not handle them with your bare hands. Please contact the Mayne Island Conservancy so that we can immediately collect the bats for analysis. Alternatively you can report dead bats to the BC Community Bat Conservation Program at BCBats@gmail.com. With this information we hope to better understand the factors influencing mortality during the summer.
- Read about bats on the BC Bats website (www.bcbats.ca)
- Bake your own bat cookies. Send us a picture!
- Learn more about habitat enhancement – Read the new Best Management Practices for Bat Boxes in BC or watch a webinar from Wildlife Conservation Society Canada
Project EduBat – bat activities for you.
BatWeek.org – the Bat Celebration CookBook from BatWeek.org! BatWeek is in the fall, but why not do some cooking while spending all this time at home? –
Information about bats and coronaviruses.