Bats could be up there with elephants as animals that never forget. A new study found that wild bats were able to remember a specific ringtone four years after learning to associate it with food.

Researchers led by May Dixon, now a postdoctoral scholar at The Ohio State University, first caught 49 frog-eating bats from the wild and trained them to fly toward a given sound by exposing them to different audio in a lab setting. The sounds began as the mating call of the bats’ favorite prey, the túngara frog, and were gradually mixed with and then fully changed to a ringtone.

The bats kept flying toward the ringtone even in the presence of other, similar tones, and they would receive a delicious piece of baitfish as a reward. Across a window of one to four years later, Dixon and her colleagues recaptured eight of the trained bats and found that they all seemed to remember the ringtone, since they would still fly toward it. Dixon led the study, which is published in Cell Biology, during her time at the Smithsonian Tropical Research Institute in Panama while she was a graduate student at the University of Texas at Austin.

“I was surprised – I went into this thinking that at least a year would be a reasonable time for them to remember, given all the other things they need to know and given that long-term memory does have real costs,” said Dixon, in a press release. “Four years strikes me as a long time to hold on to a sound that you might never hear again.”

Dixon and her fellow researchers are excited to have observed the wild bats’ memories, since bats in captivity may respond differently than those in the wild. “The environment is different and the brain is different in the wild versus captivity,” said co-author Gerald Carter, a professor of evolution, ecology, and organismal biology at The Ohio State University. The researchers hope that this study will help elucidate the relationship between animal memory and ecological traits like hunting, where long-term memory could help reduce the trial-and-error of learning to hunt rare prey.

Carter, Dixon, and the rest of the team also believe that the relationship between memory and survival may not be as straightforward as we assume: It’s possible that better memory doesn’t necessarily give animals a leg up over others. According to Dixon: “That’s why we want to figure out when these skills are actually going to help animals and when they could be a liability.”