One thing is for sure: It's a wily little critter.
This bat, found in tropical forests from Mexico to Brazil, can discover new food sources by studying the behavior of other species. It is the first example of cross-species learning in bats, researchers say, and it may illuminate how these tiny animals manage to survive as their environment rapidly changes.
To ensure that the experiment's sound really was new to the bats, the researchers worked to come up with something so hideous and unnatural that the animals wouldn't tolerate it unless they knew they'd be rewarded.
“Each pulse was a high-pitched 'Eeee, eeee,' " Patriquin said, squeaking into the phone. She hated it, and the bats did, too. “You could visibly see they were not happy, because they would shake their heads in response to the sound.”
Nevertheless, the researchers were able to train members of a similar species, the white-throated round-eared bat, to fly toward the sound in exchange for a tasty meal. By first playing the familiar sound of a katydid's chirp, then gradually switching it out for the piercing “novel cue,” the scientists taught the white-throated round-eared bats to associate the cue with dinner.
Then the experiment began: If a “naive” fringe-lipped bat was placed in the flight cage with a trained white-throated round-eared bat, how quickly would it pick up on the trained animal's food-finding trick?
Very quickly, it turns out. After an average of about 20 exposures, the fringe-lipped bats learned to follow the new sound cue, even when a white-throated round-eared bat wasn't around. They were able to pass the knowledge on to their buddies just as fast; the number of exposures required for fringe-lipped bats to learn the meaning of the sound from trained members of their own species was about the same. Only a single “naive” bat failed to learn from observing another animal.
By contrast, fringe-lipped bats that had to figure out the relationship between the squeaking sound and food on their own were rarely successful. Most of the time, Patriquin and her colleagues had to end the experiment before the bats got the hang of things.
The fringe-lipped bat “is a consummate learner,” Patriquin and her colleagues write in their report, “capable of acquiring new information about novel, potential prey from conspecifics [members of their own species] and heterospecifics [members of other species].”
And, of course, humans learn by observing the behavior of other species all the time. Our hunter-gatherer ancestors found new food sources by watching what other animals ate. Today, you might start to recognize the mail carrier's approach from your dog's insistent barking.
“From a purely scientific perspective it's interesting to understand how animals learn about the world around them,” Patriquin said. “But it also tells us how bats might learn to adapt to changes in the landscape.”
Fringe-lipped bats aren't considered a threatened species, but the rain forests in which they live and the frogs on which they feed are imperiled by climate change, habitat destruction and disease. These bats may have to shift their dietary habits or their home ranges as a consequence. If they can speed up the process of adapting by learning from their neighbors, Patriquin said, they may increase their chances of survival in this changing world.