Frog mating calls teach bats which prey to avoid

In the tropical forests of Central and South America, life hums, buzzes, and croaks. Among this symphony of animal calls, one predator has evolved to treat sound as a roadmap to food: the fringe-lipped bat.

This bat doesn’t sniff or stalk its prey like many others do. Instead, it listens. It listens to the mating calls of frogs and toads – many of which are meant to attract mates, not signal danger. But for this bat, those calls become a dinner bell.

Experience shapes survival skills

A recent study by scientists at the Smithsonian Tropical Research Institute (STRI) reveals something even more remarkable: these bats are not born with the knowledge of which frog calls signal a safe meal and which could be deadly.

They learn that over time. The study, published in Proceedings of the Royal Society B, sheds new light on how experience shapes survival skills in one of nature’s most acoustically-attuned hunters.

Bats use frog calls to hunt

Predators often rely on stealth and sharp senses to catch prey. Fringe-lipped bats have taken this a step further. They are known to eavesdrop on the mating calls of over a dozen frog and toad species that share their habitat, ranging from Panama to Brazil.

These calls, intended for potential mates, also end up attracting danger from above. The bats respond within seconds of hearing a call, swooping down to snatch the unsuspecting amphibian.

But the strategy is not without risks. Not all frogs make good meals. Some are too large to carry. Others produce toxins that can harm or even kill the bats. Just like humans screening unknown calls for spam, these bats must make a quick judgment. But unlike our phones, nature doesn’t come with caller ID.

Fringe-lipped bats seem to have developed one of their own. They ignore calls from frogs known to be unpalatable.

However, scientists had long wondered how this system developed. Is it an instinct, or is it a learned behavior? This study finally offers an answer.

Bats must learn safe frog calls

“It’s truly remarkable that these bats hunt using the calls of an entirely different group of animals in the first place, and we have wondered for a long time how these bats acquire this unusual skill,” said Logan James, STRI postdoctoral researcher and lead author of the study.

Previous experiments had already shown that these bats are intelligent and adaptable. But until now, no one had tested whether learning played a role in refining their hunting tactics.

The researchers wanted to find out if young bats start out with these auditory judgments or if they develop them through trial and error.

To do this, the team studied how adult and juvenile fringe-lipped bats responded to a variety of frog and toad calls. They tested 15 different species, including both edible and toxic options.

Young bats identify frog size through calls

The results told a fascinating story. Adult bats performed as expected. They responded more strongly to calls from palatable frogs and ignored those from toxic or too-large species.

This confirmed what earlier studies had found. But the juvenile bats behaved differently. They didn’t seem to distinguish between safe and dangerous calls. On average, young bats reacted equally to all of them, regardless of the frog’s size or toxicity.

Still, the juveniles weren’t entirely clueless. The researchers noticed that even the younger bats could identify large frogs by the pitch and tone of their calls. They avoided them just as the adults did. But when it came to toxicity, they had no filter.

This showed that while some aspects of prey recognition might be instinctive, others – particularly those involving danger – require time and learning.

Young bats need time and experience

“We have studied this fascinating species for years, and in many aspects, we understand its behavior very well,” said Rachel Page, staff scientist at STRI, and one of the study’s senior authors.

“But this was the first time we had ever tested juvenile bats. It was so interesting to see that, like human children, young bats needed time and experience to hone their discrimination skills.”

The comparison to human development is compelling. Just as young children don’t start life knowing what foods to avoid, young bats must also test, fail, and adapt. Their early mistakes could be deadly, but these experiences are crucial for shaping more refined behavior as they mature.

This learning curve likely mirrors processes in many other species, not just fringe-lipped bats. It opens new questions about how young animals learn to navigate the complexities of their environments—and survive.

A larger pattern in nature

This study marks the first time researchers have directly compared eavesdropping behavior between adult and juvenile predators like bats and frog-eating species. But it might not be unique to this species.

Many predators rely on sound to hunt. If experience plays such a vital role for fringe-lipped bats, it could be just as important for others that must decipher a confusing, noisy world.

“This study highlights the power of development and learning to shape eavesdropping behavior, an insight that may extend far beyond bats to other predators also navigating complex sensory environments,” said Ximena Bernal, research associate at STRI, professor at Purdue University and one of the study’s senior authors.

“We hope it will inspire other scientists to examine how early experience modulates predator-foraging decisions.”

Listening to learn, surviving through sound

This research provides more than just insight into the life of one bat species. It emphasizes the importance of development in shaping behavior. The fringe-lipped bat begins life without the skill to discern between friend and foe.

Through experience and repetition, it learns. Over time, its reactions become precise. Each call becomes a clue, and each choice a matter of survival.

In a world where sound carries both promise and peril, the fringe-lipped bat shows how nature equips even its smallest hunters, like frogs and bats, with the tools to listen, learn, and live.

The study is published in the journal Proceedings of the Royal Society of London B Biological Sciences.

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