Listening in the Dark (2018) takes a series of subtle but penetrating soundings of human beings’ impact on the natural environment. While there is a growing sensitivity to the ecological damage we are causing, we can also be strangely blind to things that happen outside of our consciousness. A creature that has often fallen beneath our radar is the bat. Undisturbed, and largely unchanged, for millions of years, its nocturnal rhythms are being increasingly interrupted by the presence of wind turbines. While noting how these new (and well-intentioned) technological developments are affecting the atmosphere in ways we do not always appreciate, Brennan also illuminates how scientific research has revealed a whole sensory dimension that we were previously oblivious to.

A case in point would be Donald Griffin’s pioneering studies of bats, which opened our eyes (and ears) to their extraordinary methods of navigation, and provided the basis for an understanding of echolocation. Combining archival footage of the seminal Griffin/Galambos experiment with footage shot on location in Scotland, Brennan’s film looks back over an unimaginable span of geological time, enlisting fossil records and other evidence to remind us of the mysterious landscape beneath our feet as well as the unheard soundscape going on above our heads.