There are certain skills that once learned, rarely need to be relearned, such as riding a bicycle. Many studies focusing on learning and long-term memory consider only a few animal species.
Now, a study published in Current Biology reveals the first account of long-term memory in bats of the species Trachops cirrhosis.
“These bats represent an excellent emerging model organism for studying sensory and cognitive ecology,” explained biologist M. May Dixon, lead author of the study, who just completed her doctoral studies at the University of Texas, Austin, USA. “Learning plays an important role in their lives,” added Dixon.
The ability of bats to learn and retain information
Bats’ ability to learn and retain information means that when hunting frogs, their main prey, bats don’t have to continually relearn the sounds that indicate a frog is good to eat, poisonous or too big to carry.
Dixon and his colleagues trained 49 wild bats to respond to cell phone ringtones broadcast over loudspeakers. Bats that responded to two of the bells found a reward (a fish) on one of the boxes each time, but when they responded to three other bells, the bats were never rewarded. They quickly learned to fly to the speakers when the bells indicated a reward and not to react to the other tones. The bats were microchipped and released back into Panama’s Soberania National Park.
The researchers recaptured eight of the trained bats, between one and four years apart, and then broadcast the experimental sounds again. Bats recognized and reacted to the two bells suggesting rewards even four years later. By comparison, the experiment included 17 untrained bats that pricked their ears but did not fly to where the sounds came from.
Studying long-term memory is very difficult
The ringtones chosen for the experiments were specifically chosen so that they did not appear to be of natural origin, being a message alert and the sound of unlocking a car, according to EurekAlert.
The study led to several questions about how memory works in bats and other animals, including the metabolic cost of memory.
“I’m interested in memory capacity in animals and what causes short-term and long-term memory, what ecological conditions lead to certain memory spans, what’s important to remember and what can be forgotten,” Dixon explained. “But studying long-term memory is very difficult, because it takes a very long time. Memory testing in captive animals, even if it is more convenient, is not necessarily representative of wild animals,” added the researcher.