On the day after Halloween as we move closer towards winter I thought it would be appropriate to talk about one of the holiday’s most emblematic creatures – the bat. Some are facing a possible extinction level event due to White-nose Syndrome which is killing several hibernating species in the northeast U.S. and spreading across the country rapidly. Most people know that bats hibernate in caves (thanks Batman), and each hibernaculum can have tens of thousands of bats or more. Even with these high numbers there are mortality rates nearing 100% in some locations! This USFWS graphic posted on Facebook earlier this week provides a succinct summation of what is occurring.
In the past seven years millions of bats have died because of White-nose Syndrome with the fungus Pseudogymnoascus destructans having been labeled as the cause. Many have remarked or speculated on how something like this could occur so suddenly and move so rapidly, especially as we see bees dying in similar ways due to colony collapse disorder and chytrid fungus blasting its way through amphibians and wiping them out across the world. In talking about this with Twan, an extremely accomplished and well-versed animal ecologist and conservation biologist who still travels the world working on chytrid and countless other projects, he mentioned how once it was intriguing that again we had a common fungus in play. This one thrives in the conditions one would find in a hibernaculum – cool and damp – which made it all the more unexpected to see it jump to these warm bat bodies.
White-nose Syndrome does not kill the bat itself as it instead upsets their immune system and basic functions and keeps them overly active and disturbed. This eventually leads to them running their bodies too much at a time when they should be hibernating and causing starvation, among other symptoms. The question will be what happens next – will it burn out when massive population losses are seen across the continent or will it persist and keep killing? In the case of chytrid fungus there are now areas that have certain amphibians living with the chytrid that are able to tolerate it to enough of a degree to survive and reproduce.
Eastern Pipistrelle (Perimyotis subflavus) discovered out of range in winter. Is this increasingly observed aberrant wintering/migrant behavior related to White-nose Syndrome?
Twan also told me a story about surveying a hibernaculum in a cave in Connecticut with Little Brown Bats that was a particularly terrifying experience. Bending over and walking through the cave the deceased bat bodies covering the ground sounded like popcorn as they tried to avoid stepping on too many of them. It is a horrible irony that once again we see such unique and vital creatures being decimated at these levels, and perhaps this is another set of animals that is being weakened and left vulnerable by something we are putting in the environment, such as neonicotinoids. We need bees to…well, survive on this planet in the manner that we are right now thanks to their pollination. And we need bats in North America to clean the air of insects that threaten agriculture and health. Bats eat quite a bit of the pests that would otherwise be eating a lot on our farmlands.
As West Nile Virus, Eastern Equine Encephalitis and other mosquito-borne diseases spread (once again from the northeast, what a coincidence, huh? I don’t think so…) they are going to be able to move through perhaps billions or trillions of mosquitoes that would have been otherwise eaten by these now dead bats. Yes, like Purple Martins, mosquitoes are tiny meals that likely do not make up much of a bats diet in the wild despite some marketing campaigns, but when you remove millions of bats that would have otherwise lived far longer it is not a stretch to think of the totals in those magnitudes over the course of many years. When you add in other new sources of bat death, such as wind turbines, and the more classic human-related direct causes, it is clear they have a very difficult road ahead of them. More observations, research, and critical thinking is necessary, and we have to continue to look at what we are putting into the planet that is assisting in annihilating animals en masse on a global scale.
Scott Kruitbosch
Conservation & Outreach Coordinator
Photo 1 © USFWS; photo 2 © Twan Leenders
