There is a nocturnal arms race taking place above our meadows and wetlands. The race for survival between Grey Long-Eared Bats and their moth prey has been evolving for millennia – but who will win?


The reason Grey Long-Eared Bats echolocate so quietly is a prime example of co-evolution. There is a race going on between bats and noctuid moths – a family of moths that have evolved to ‘hear’ bats coming by developing auditory receptors to pick up echolocation, and respond accordingly. They may make evasive manoeuvres, respond with their own ultrasonic clicks to confuse the bats or simply drop out of the sky! In response, Grey Long-Eared Bats have evolved to echolocate more quietly, hence developing extremely long ears, enabling them to hear themselves!


Everything about the Grey Long-Eared Bat has developed harmoniously to enable it to successfully hunt evasive moths and stationary insects; super-quiet echolocation and super-long ears to counteract that. Large eyes so it can switch off its echolocation and potentially hunt purely through vision. Broad, compact wings with a large wing flap to enable slow, manoeuvrable flight – allowing feeding of prey through both hawking in flight and gleaning insects from vegetation.


A study in 2011 showed that the most common prey species for Grey Long-Eared Bats is Noctua pronuba or the Large Yellow Underwing (one of the noctuid family). So, maybe the Grey Long-Eared Bat is winning the arms race. However, both species face a bigger challenge. The impacts of a changing climate and a significant loss of habitat are pushing many species to the edge. Hopefully Back from the Brink can counter these impacts so these species can continue their evolution for millennia to come.



Craig Dunton

Grey Long-eared Bat Project Officer.



(c) Alexandre Roux, Flickr,