Greater Mouse-eared Bats Put Effort in Greater Assets in Hunting Prey Profitability When Foraging

Despite the higher risk of failure, foraging greater mouse-eared bats devoted more resources to hunting large, difficult-to-catch ground-dwelling insects rather than smaller, more easily caught flying insects.

These findings, published today in eLife, showed that these bats use high-risk, high-reward tactics to hunt more nutritious ground-dwelling insects but switch to hunting airborne insects when environmental conditions make hunting ground prey impractical.

The research helps us understand how these small predators meet their daily energy requirements and may inform bat population protection strategies against future environmental changes caused by human activity.

Bats' High-Risk, High-Gain Hunting Tactics

(Photo : Getty Images)

Previous research on predator-prey interactions has primarily focused on large predator hunting strategies, as per Phys.org.

Despite the critical role that smaller, more abundant predators play in ecosystems around the world, little is known about them.

The bat is an example of a small, highly specialized predator.

Since they are the only mammal with powered flight and use echolocation to sense in darkness, they can fill a specific ecological niche, hunting at night to reduce competition from rival predators such as birds.

Because of their small size and high metabolic rate as a result of powered flight, they require a high and consistent input of energy from their food.

Bats are widespread and common predators that are critical to many ecosystems worldwide, but their species and numbers are declining, according to lead author Laura Stidsholt, a Villum International postdoc at the Leibniz Institute for Zoo and Wildlife Research in Berlin, Germany.

Understanding how bats adapt their foraging strategies in changing environments is therefore critical for forecasting their responses to future ecological changes.

Stidsholt and colleagues studied the foraging strategies of the greater mouse-eared bat, which captures prey in two ways: targeting small insects in the dark sky and scouring the ground for large insects.

Because studying detailed hunting behaviors in the wild is difficult, it is unclear what factors influenced the choice of hunting ground or aerial prey in bats.

To fill this void, the researchers fitted 34 greater mouse-eared bats with miniaturized backpacks equipped with microphones.

This allowed them to record the bats' echolocation behavior, movement patterns, GPS location, and chewing sounds, which they used to determine whether or not the hunt was successful.

They noticed that the dominant foraging tactic was mostly consistent across the bats on a given night, implying that each bat adapts its strategy to environmental conditions like rain or wind.

The researchers counted 3,917 prey attacks, with each bat catching an average of 25 aerial insects and 29 ground insects per night, indicating their reliance on both food sources.

The bats attacked prey on the ground more frequently, with an average of 80 attacks per night versus 36 aerial attacks.

Attacks on ground targets were more than twice as likely to fail, raising the question of why bats devote their limited energy to a riskier strategy.

Also Read: Bats and Whales Share Behavioral Similarities

Echolocation

Echolocation is an incredible technique used by bats to navigate and hunt in the dark.

When a bat makes a sound, it travels through the air until it collides with an object and returns to the bat as an echo.

Based on the time it takes for the echo to return and the change in frequency of the sound, the bat can determine the distance, size, and shape of the object.

This enables bats to detect and capture flying insects with incredible precision.

The concepts of echolocation and sonar are very similar.

Echolocation, also known as bio sonar, is the use of echoes to detect objects in bats and other natural creatures, as per WikiDiff.

Sonar, an abbreviation for Sound Navigation And Ranging, is a technique that uses sound propagation (usually underwater) to navigate, communicate with, or detect objects on or beneath the water's surface, such as other vessels.