And testing memory in captive animals, even if it’s more convenient, isn’t necessarily representative of what animals can remember in the wild.” She wants to go back to the BatLab, directed by STRI staff scientist and co-author Rachel Page, to learn more. “But studying long-term memory is very difficult, because it takes a long time by definition. “I’m interested in memory capacity in animals and what causes long-term or short-term memories, what ecological conditions select for different memory lengths, what is important to remember and to forget,” she explains. This experiment raises more questions regarding how memory works in these bats and other animals, including the metabolic cost of remembering. To make sure that the bats were not responding to every sound they heard, she played a pure tone, and most of the bats did not fly to it, only twitched their ears. Sort of like a generalization of memory.” “Or it’s possible that they couldn’t remember the exact difference between the ringtones, and that extinguished sound was close enough to the rewarded one that they decided to check that out too. “It’s possible that they remember the extinguished sound, but enough time had gone by that they thought to check it out once more,” said Dixon. The ringtones they chose for the experiments, the ping of an incoming text message alert, and the beep of a car being unlocked, sounded clearly human-generated, so that the bats wouldn’t casually hear them in nature, but frog-like enough that the bats were interested.Īs for the extinguished tones, the unrewarded ones that the bats learned to disregard, researchers played one of them to the recaptured bats, and six of the eight trained bats approached it. When Dixon was working as a STRI intern with PhD student and co-author Patricia Jones to find out if the bats could learn which novel tones meant a reward by watching the responses of other bats, she realized that she could also find out if the bats could remember the tones. For comparison, the experiment included 17 untrained frog-eating bats that usually twitched their ears attentively but did not fly to the sounds.

Researchers recaptured eight trained bats between one to four years later, and when they played the experimental sounds again, the bats recognized and responded to the two rewarded ringtones even four years later. The bats were then microchipped and released back into Panama’s Soberania National Park. They quickly learned to fly to the speaker when ringtones indicated a snack, and not to respond to the other tones. Bats responding to two of the tones found a bait fish reward on the speaker every time, but when they responded to three other tones, they were never rewarded. The bats’ ability to learn and retain information means that when they are hunting frogs, their main prey, they don’t have to continuously relearn which frog calls indicate that a frog is good to eat, poisonous, or too big to carry.ĭixon and colleagues trained 49 wild bats to respond to cellphone ringtones played through speakers.

Long term memory pictures