This tiny bat hunts like a lion, but better

To observe how fringe-lipped bats (Trachops cirrhosus), tiny meat-eaters native to Panama's forests, hunt in their natural environment, scientists fitted 20 individuals with miniature "backpacks." These biologging devices tracked their every move and captured the sounds around them, offering a detailed view of their nocturnal behavior.

The recordings revealed a surprising finding: these bats target large prey such as frogs, birds, and small mammals. Using a patient "hang-and-wait" technique and an exceptionally acute sense of hearing, they can detect the slightest sound made by their prey, locate it swiftly, and strike with great precision.

According to the study, published in Current Biology, a single bat can consume nearly its own body weight (30 grams) in one meal, placing it among the most energy-efficient predators known.

A puzzling exception in nature

The researchers sought to solve a long-standing biological puzzle.

In most animals, size determines how they hunt. Big predators like lions and polar bears can afford to pursue large, energy-rich prey because their slower metabolism and greater energy stores let them endure repeated failed hunts. Small predators, in contrast, burn energy quickly and must eat often, so they typically focus on smaller, plentiful prey that are easier to catch.

Yet a handful of bat species break this rule. Nine known types of bats are true carnivores, meeting more than half of their energy needs by eating vertebrates such as frogs, birds, or even small mammals. This raises an important question: how can such small creatures with limited energy reserves survive by hunting large and rare prey, a tactic that usually requires tremendous effort and frequent failure?

To explore this mystery, the team studied the fringe-lipped bat as their model species.

These bats are known to feed on small túngara frogs, so researchers expected the recordings to show many quick captures of these tiny amphibians.

Hunting more like lions than bats

What they found instead overturned expectations. The fringe-lipped bats behaved more like big cats than other bats.

They remained motionless for long periods, waiting to ambush unsuspecting prey. When they struck, their attacks were swift and precise. After a successful hunt, they often rested for much of the night, just as lions and leopards do after a big meal.

Movement and sound data showed that the bats used a combination of hearing, sight, and echolocation. Their ability to detect low-frequency sounds helps them eavesdrop on the mating calls of frogs. This sensory mix lets them locate and capture large prey with remarkable accuracy.

Big hunters in small bodies

"It was incredible to discover that these bats hunt like big predators trapped in tiny bodies," says lead author Leonie Baier, a Marie Skłodowska-Curie postdoctoral fellow at Aarhus University and research fellow at STRI. "Instead of spending the night constantly on the wing, they wait patiently, strike with high precision, and sometimes end up catching enormous, energy-rich prey. The discovery that an animal this small can do this really turned our assumptions upside down."

During the study, the bats spent about 89 percent of their time resting to conserve energy. When they did take flight, their attacks were brief -- most lasted under three minutes, and the average hunting flight just eight seconds.

Their success rate was extraordinary: they succeeded in roughly 50 percent of their hunts, far exceeding the success rates of large mammals such as lions (about 14 percent) or polar bears (as low as two percent).

Meals that test their limits

The prey these bats caught were larger than scientists anticipated, averaging about seven percent of the bat's own body weight. That's like a 70-kilogram person eating a five-kilogram meal.

Some even captured prey nearly their own size, including the sizable Rosenberg's gladiator tree frog, which can weigh up to 20 grams. The researchers could estimate prey size by measuring how long the bats spent chewing on it -- the longest meal recorded lasted 84 minutes.

Experience sharpens skill

Older bats proved especially adept at handling bigger prey, suggesting that hunting skill improves with practice. These bats are already known for their long memory of specific frog calls and their ability to learn new techniques by watching others.

"We wanted to understand what these bats are actually doing out there in the dark -- so we listened in, much like the bats themselves listen to their prey," says Laura Stidsholt, assistant professor at Aarhus University and senior author of the study. "With the data from our biologging tags, which combine high-resolution sound recordings with movement data, we were able to reconstruct entire hunting sequences in the wild. In this way, we experienced the forest through the bats' ears -- revealing a hidden world of patience, precision and survival in the dark."