Expert explores the fascinating lives of bats
By Sue Tiffin
Published June 7, 2018
Utterly intriguing are the words Brock Fenton uses to describe the small animals he's been studying for more than 40 years, but the crowd gathered at the Minden Hills Cultural Centre to listen to the professor emeritus of biology at University of Western discuss his passion might describe his lecture in the same way.
He speaks quickly, as though he's so used to giving this talk he could do so in his sleep but also maybe so that he can cover the wealth of information he wants to share with the audience attending the Haliburton Highlands Land Trust'sExploring the Lives of Bats presentation on May 26.
Around the world there are 1,260 bat species - in Canada, there are currently 19 identified species of bats – eight in Ontario – and four of those bat species have been classified as being endangered.
“One of the recurring themes here is how much we don't know about bats,” he said. “A lot of the questions we had in 1968 are still the same questions we have now. One of the neat things about bats is just when you think you know something, they remind you that you really don't. That can be embarrassing but it also makes life very difficult. If you're trying to figure out what the conservation status is of an organism, whether it's a plant or a bat or anything, you need to know how many there are. We don't have that kind of information for any of the bats in Canada. We don't know how many there are today. We don't know how many there were 50 years ago, 100 years ago. So those are the kinds of questions we need to know the answers to, and we just don't. We don't know how many there are, but we know there are a lot fewer now than there ever were.”
Bats have been facing an unprecedented population decline, leading the HHLT to launch a bat project last year to identify bat species and their distribution throughout the county. All eight species found in Ontario, including the four endangered species, have been found in Haliburton County.
Although some bats in the wild can live to be as old as 45, they face numerous challenges in keeping population up, right from birth.
Mating occurs in August or September, but a female bat will store sperm in her uterus until after hibernation, when an egg becomes fertilized. Generally bats produce one offspring a year, though some species have twins – which often have different fathers – and at least one species can have up to four babies at a time.
Baby bats are basically 30 per cent of their mothers weight at birth, and the mother produces 75 per cent of her body milk every day – as Fenton explains, that's the equivalent of a 45 kg woman producing 33 kg of milk a day.
“Mother bats are extremely dedicated to their young,” he said. “They invest a huge amount of time in them.”
Despite that care, there is a high rate of mortality for bats, with 60 per cent not making it through the first year, likely because they don't put on enough weight to make it through the winter.
Fenton spends much of his time, even on vacation around the world, photographing and studying bats in their natural habitats and has had the rare opportunity to see some young bats with their mothers.
Though there is keen interest in bats, biologists and conservationists still don't know some basic biology information about them, such as whether they have young every year, or every other year, and at what age they have their first young.
Fenton shares some of the photos he's taken on his travels throughout his presentation, including the classic shot of a bat with mouth wide open, wings outstretched.
“When you see a bat like this flying with his mouth open, it has nothing to do with a hostile threat,” he explains. “The bat's producing echolocation calls as it flies along, and it needs to have its mouth open to do this. My good friend is fanatic about protecting bats. He never likes to share images of bats with their mouths open because it sends the wrong message. But in this case, it isn't an aggressive message. It's not like facing down a doberman with its mouth open. Besides the difference in size –these guys are about 15 grams. It's just the way they get around.”
Identifying bats based on signals can be tricky, like identifying bird song.
“The nice thing about bats is that they use echolocation, or biosonar,” said Fenton. “That means they'll tell you all about themselves. You just have to learn how to listen to what they're saying.”
It was in 1794 that Italian Lazaro Spallanzani discovered echolocation, or biosonar when he realized that an owl could not navigate around a room in which the candle had been blown out, but a bat could. Using a series of experiments that included materials such as ribbons and bells, he was the first to acknowledge the unique ability of a bat in getting around. In 1944, Donald Griffin – with the help of since-developed bat detectors, was able to expand on Spallanzani's research. Echolocation – using sound to see – is not something that is characteristic of all bats, but is also used by some whales, some shrews, some birds and some blind humans to basically detect a hard surface on a soft background.
“That's relatively easy to do,” said Fenton. “You can do that. You know that if you go into a room that's empty, even if you're blindfolded, you can tell from how the room sounds that it's empty as opposed to a room that has furniture in it, it sounds different. So it's no big deal.”
Simple science figured out the echolocation and its intricacies, including that bats can't broadcast and receive at the same time – the outgoing signal is so strong it deafens the bats in the returning echo. As the bat gets closer and closer, its calls get short and shorter so the bat doesn't deafen itself. So bats design their calls very actively, and then analyze information in the visual part of the brain, not the acoustical part.
“The guy, or these guys, had a question,” said Fenton. “It isn't that they had a lot of money to buy fancy equipment. Ribbons and bells and a simple bat detector. If you have a question and a way to manipulate things you can find out an answer. It's a good indication of how science works, and often does.”
Bats eat a vast array of insects, but the technique used to analyze bat droppings and determine what they're eating doesn't tell how many insects they're actually eating.
“The disconnect is that people think if they have bats, they won't have any mosquitoes,” said Fenton. “We don't have any evidence of that.”
Throughout the presentation, Fenton noted characteristics believed to be true of bats that aren't particularly factual.
“Bats see really well, so when people talk about bats being blind, that's just a mistake,” he said. “We don't know of any bats that are blind.”
As far as scientists and researchers knew, bats went south in the winter – but they didn't know how far south they go, just that they go. Using motus tags, more understanding of bat travel has occurred through tracking their movement.
“One of the things we're discovering it that the animals don't read the literature,” said Fenton, telling a story of a hoary bat that should have been going south based on our understanding, but instead went to Windsor for the weekend, and then turned up in Niagara Falls. “So a motus tag tells you all kinds of things that the animals are doing that we never knew. And of course this only makes it more interesting because all the things we kind of take for granted. The animals are on such a short energy budget, how could they possibly do that, well, it turns out the bats don't read the literature and it turns out that birds are just as bad, they don't pay any attention to what everybody thinks they do.”
Besides a high rate of mortality after birth, bats face other challenges that make them particularly vulnerable from a conservation point of view.
“People tend to be afraid of bats, tend to think they're dangerous,” said Fenton. “There doesn't necessarily seem to be any good reason to think those things, but that affects people's views of things and then affects the view people have on the animals.”
Though bats, like any mammal, can carry rabies, not all do, and bites are uncommon. Bats can transmit histoplasmosis, a lung disease, but it's also possible to pick that up from pigeon or chicken droppings. According to Fenton, bats simply have poor public relations.
Wind turbines can be bad news for a bat, but that risk could be reduced if wind companies would reduce the cutting speed to 10 metres a second.
“We have eight species in Ontario, but we do not know how many there are,” said Fenton. “So if you find 10 hoary bats dead under a wind turbine, you don't know if it's 10 of 100 that flew over or if it's 10 of 15 that flew over. You have no way of knowing. It makes it very difficult to put what you're seeing into perspective. But it's not getting struck by the blade that kills the bats, it turns out the negative pressure behind the blade causes an embolism, so basically their lungs explode and that doesn't do them very good at all.”
Unfortunately for huge numbers of bat populations, white nose syndrome was introduced to the United States from Europe, likely by accident, in 2005.
“It's really bad news and there doesn't seem to be any good news in that story,” said Fenton, who relayed a story of researchers in New York studying bat populations in three caves in that area. “In March 2005, they go into one of those caves, and instead of 30,000 live bats on the ceiling, there's 30,000 dead bats on the floor. And this is what was happening to the sites there. By 2010 it was here in Ontario. The really bad news is that by last week it turned up in Newfoundland. And then last week it also turned up in Manitoba, so it spread bat to bat.”
Fenton has seen a decline in bat populations in caves near Renfrew – where once he saw tens of thousands of bats in those caves, now he sees a couple hundred, estimating about a 95 per cent decline in the population of some bats.
“It's only bats that hibernate underground in caves and mines that are exposed to it or vulnerable to it,” he said. “The other bats probably aren't affected by it at all. Not because it doesn't get them, but because they don't ever go there. It's hibernating underneath that matters.”
A bat in the winter, sound asleep, has a heart rate of about five beats a minute. The same bat's heart, when the bat is flying in the summer, beats 1,200 times a minute.
“What's important for hibernating bats is to not be disturbed, because to wake up from freezing costs the bat as much energy as it takes to save for 60 days of hibernation,” said Fenton. “White nose disrupts that schedule. So instead of waking up after 60 days, they wake up two to three times a week and they just burn themselves out, usually by January. And there is no recourse – they can't go out of the cave when they're hibernating in the middle of winter and catch food. White nose, the fungus, is a symptom of what causes the problem. It's disrupting hibernation that matters.”
Despite research, a solution for white nose syndrome has not yet been found.
“There's a lot of people concerned about it but there doesn't seem to be any magic bullet,” said Fenton.
There are things we can do for the bat population, and one of those acts is to hang a bat house or bat box on properties to help give bats a safe place to roost and hibernate.
Bat Box Building Workshops will be held on Saturday, June 9 at the HHOA Fish Hatchery and Saturday, July 21 at Abbey Gardens. Call 705-457-3700 to sign up or get on a waiting list. A new HHLT publication, Best Management Practices for Bats, is available on the HHLT website at haliburtonlandtrust.ca. Information about the second year of the Bat Project is available at the HHLT web site. Bat observations can be reported to Christel Furniss at firstname.lastname@example.org.