Many animals adapt their diets when their environment changes and new food sources become available. New research examines dietary adaptation in long-fingered bats (Myotis capaccinii), which are generally thought to consume only insects, but have occasionally been observed eating fish.
To investigate the origins of fishing behavior in long-fingered bats, Ostaizka Aizpurua and colleagues from the University of Copenhagen, Denmark, conducted a field study in Valencia, western Spain. They compared a community of long-fingered bats known to eat fish at a golf course pond near the city of Dénia with a community of strictly insectivorous bats at a stream pool near the town of Ròtova. The researchers compared the bats’ reactions to insect-like (stationary) and fish-like (moving) prey targets.
Bats from both communities could attack the fish-like targets, and they made deeper, longer dips when the fish-like targets were submerged underwater than when insect-like targets were used. However, the differences between the two modes of attack were exaggerated in the bats used to eating fish, suggesting that these bats had previously honed their technique to improve their chances of catching a snack.
The results suggest that these bats developed their fishing technique when fish prey became available, and that it arose from a primary hunting reaction shared by all long-fingered bats. All individuals seem capable of detecting and capturing fish, but under appropriate environmental conditions, they may be able to improve their technique by experience and/or social learning. Further research could explore how long it takes for long-fingered bats to improve their fishing techniques, which may provide new insight into mammalian learning processes.
Image Credit: Antton Alberdi and Ostaizka Aizpurua
Reference: Aizpurua O, Alberdi A, Aihartza J, Garin I (2016) Fishing Technique of Long-Fingered Bats Was Developed from a Primary Reaction to Disappearing Target Stimuli. PLoS ONE 11(12): e0167164. doi:10.1371/journal.pone.0167164