Long-fingered Bats Learn to Fish Disappearing Targets

While some people mistakenly think bats are fierce predators, the long-fingered bat species actually eat only insects. A new research from the University of Copenhagen, Denmark and the University of the Basque Country, Spain has been published in the open-access journal PLOS ONE and it features a startling discovery: most long-fingered bats may be instinctively able to catch fish.

Ostaizka Aizpurua from the Natural History Museum of Denmark and a team of researchers believe that animals could alter their diet when they experience a change in environment and have a different food supply available. These long-fingered bats, though previously thought to only eat insects, have been discovered in previous studies to eat fish.

In order to find out the origins of fishing behavior in long-fingered bats, a field study was conducted in the Valencia, Western Spain by Aizpurua and the rest of the research team. A community of long-fingered bats known to eat fish at a golf course pond near Dénia was compared to a community of strictly insectivorous bats at a stream pool near Ròtova. Their primary method for comparison was to test the bats' reactions to insect-like or stationary and fish-like or moving prey targets between the two bat communities.

When targets were submerged underwater, both fish-eating and insectivorous long-fingered bat communities made deeper, longer dips to attack moving fish-like targets. One marked difference observed by the researchers was that the bats used to eating fish had a more exaggerated mode of attack. This could mean that this community of bats had experience in honing their technique to improve their chances of catching fish.

The researchers believe this could mean the long-fingered bats developed the fishing technique when fish prey became available. Though all long-fingered bats seem capable of finding and catching fish, it would take experience and social learning to improve their technique. Further research is needed to explore the length of time it would take for the long-fingered bats to enhance their fishing techniques and gain new perspective into the learning processes of mammals.