Froggy bats trained by scientists to associate a phone ring with a tasty treat can surprisingly remember what they’ve learned after up to four years in the wild, a new study has revealed.
In research published in the journal Current Biology On Monday, scientists familiarized 49 bats with a series of taps that caught their attention and trained them to associate flying toward just one of the tones with a reward — a bait snack.
They recaptured eight of the bats and re-exposed them to food-related touch between one and four years later.
All the bats flew towards the sound, and six flew to the speaker and snatched the food reward, the scientists say, suggesting the bats were hoping to find food.
“I was surprised – I went into this thinking that at least a year would be a reasonable amount of time for them to remember, given all the other things they need to know and considering that long-term memory has real costs,” the study’s lead author. May Dixon of Ohio State University said in a statement.
“Four years seems like a long time to hold back a sound you may never hear again,” Dixon said.
In the first phase of the study, frog-eating bats captured for a series of cognition tests were exposed to a highly appealing sound in the laboratory. These included the mating call of the male tungarian frog, one of the preferred prey of this bat species.
When bats flew with this sound, they were rewarded with a piece of bait placed on the mesh above the speaker.
The researchers then mixed the sound and gradually replaced it with a ringtone, but the payoff was the same.
They also introduced three other touches, none of which were connected to a food reward.
Scientists trained the bats to discern the differences between touches, and eventually, they no longer flew towards unrewarded sounds.
Each bat, according to the study, secured at least 40 snacks flying into the trained touch over 11 to 27 days, and all of them were microchipped and returned to the wild.
The researchers then recaptured them and identified eight of the bats from the initial test by their microchips.
In a follow-up test, they found that all eight trained bats quickly flew to the sound and were able to tell the difference between that ringing and a new, steady pitch, although many flew to an unrewarded sound from initial training.
In comparison, scientists say that 17 untrained bats that were exposed to these sounds mostly just twitched their ears in response to the sounds and didn’t fly towards them.
“The study taught us a lot because there are relatively few studies of long-term memory in wild animals and we still don’t have a systematic understanding of long-term memories in nature,” Dixon said.
“If we can collect additional data on different species of bats, we can separate this out and see which life histories select for long memories.”
While several studies in the past have documented memory in species ranging from fish, birds and bats to goats and primates, with some, such as sea lions, demonstrating long-term memory for 10 years, the researchers say these were mostly performed in animals that lived in captivity. all the time.
“Being able to study memory in nature is important,” said Gerald Carter, another co-author of the study.
“You can’t necessarily extrapolate from the wealth of data we have on animals in the lab to what they’re facing in the wild, where there’s a lot more they need to remember. The environment is different and the brain is different in nature versus captivity,” explained Carter.
While long-term memory gives humans an intelligence advantage, scientists say memory flexibility — also called adaptive forgetting — could be important for survival.
“It is not always true that being the smartest or having the longest memory is really advantageous. Research has shown that fruit flies selected for memory enhancement cannot compete as well with other fruit flies,” Dixon said.
“Just because it’s useful for humans to be so smart and have such good memories doesn’t necessarily mean it will be the best thing for other animals,” he added.
In other studies, scientists hope to understand when these memory skills are actually helping the animals and when they might be a risk.