A new fungus that inflicts bats living in caves and mines, causing most of them to die, does not appear to be devastating their urban cousins.
White nose syndrome, originally discovered in New York state in 2007, has been linked to a fungus found on the wings, ears and muzzles of infected bats. The disease has a 95 per cent mortality rate, and has since spread to ten other states as well as Ontario and Quebec. It is being blamed for the widespread collapse of many bat colonies in North America.
At night, bats consume huge amounts of insects that damage crops and forests and that cause human disease, such as mosquitoes infected with West Nile Virus. A study conducted by Boston University in 2010 predicted regional populations of little brown bats in the Northeastern United States will collapse to less than one per cent of their current numbers within two decades.
Urban exception
But evidence from Canada’s largest wildlife control company, Humane Wildlife Control, indicates that the big brown and little brown bats typically living in attics and roofs in urban areas do not seem to be affected by the disease. The company makes hundreds of service calls between July and September each year when young bats begin to fly around living areas.
“We just haven’t seen evidence of white nose syndrome in the many urban bats we deal with in Ontario and Quebec,” said company president Bill Dowd. “People shouldn’t assume that this disease is going to kill the bats so they can just ignore them,” he added.
Rabies is a worry
Most of the recent human rabies cases in Canada have been caused by a strain of rabies transmitted by bats and people are advised by public health departments to seek medical attention immediately if they may have come into contact with a bat. The small bite of a bat can go undetected, especially if someone is sleeping when they are bitten. However, there is no evidence to date that the white nose fungus is harmful to humans.
Urban, rural differences
Dr. Paul Faure, a researcher in the Department of Psychology, Neuroscience and Behaviour at McMaster University and one of Canada’s leading experts on bats, said that there are still many unanswered questions about white nose syndrome. He explained the reason no one is seeing evidence of the disease with urban bat calls is that attics and roofs tend to have different living conditions than caves and mines.
Faure said, “The big brown bats living in urban areas are not immune to the fungus; however, because urban roosts tend to be warmer and dryer than hibernation sites like mines and caves, bats living in the walls and attics of homes may not be exposed to the conditions that promote the growth of the white nose fungus.”
He added, “This might be good News for urban bats as their populations may not be as affected as the ones living in more rural and remote areas.”
Urban wildlife adapted
This difference between urban and rural bats is also typical for most other urban wildlife such as raccoons, squirrels, birds and mice, which have learned to adapt and often thrive in higher populated areas.
“These animals, like the bats, have done quite well in urban areas where food and shelter is plentiful,” said Dowd. “If given the choice between an outside den site or a nice safe and cozy attic, it’s pretty obvious which one they prefer,” he said.
As for the future of Ontario bats, Faure said much more research is needed.
