This sharply contrasts with mass mortalities reported in North America where hundreds or thousands of dead bats are found in hibernacula towards the end of the hibernation period.
Assuming that some of the past mass mortality events in hibernacula could have been a result of a disease is not beyond the realm of possibility.
Such a study would be important, to account for why WNS suddenly appeared in hibernacula that had no prior history of it across three decades of recorded observations.
For example, the small amount of surplus water produced as a byproduct of fat metabolism in solitarily hibernating M. lucifugus does not compensate for EWL except at levels of relative humidity greater than 99%, and this species regularly incurs water debt during bouts of winter torpor, even in hibernacula with near-saturated air [ 23].
Higher temperatures in hibernacula have been associated with more frequent arousals in Rhinolophus ferrumequinum [30], [31], [32].
Finally, bats may aggregate without forming any social bonds, due to limited roost availability, especially in hibernacula [3].
In countries/regions (i.e. the Netherlands, Northwest Germany) where M. dasycneme is more commonly encountered in hibernacula, G. destructans prevalence can reach high levels in that species.
It is nevertheless too early to conclude on this association between G. destructans prevalence and the hibernation duration, as other factors would need to be considered such as for example, the higher temperature observed in hibernacula in the Mediterranean region compared to other regions in Europe [29].
Although rare, hibernacula of a few thousands and up to about 34,000 individuals are also known for species of Myotis in Europe [34], [35], [38], [39], [40], [41].
The common little brown bat (Myotis lucifugus) hibernates, along with the endangered Indiana bat (Myotis sodalis), in many hibernacula in the Northeastern United States, including caves and mines in upstate New York [9], [10].
