6 Fascinating Animal Facts: Hearing Edition

The animal kingdom has developed a surprising variety of hearing — or non-hearing — styles based on anatomy, environment, and necessity. Let’s look at a few.

Did You Know Cats Have Pockets?

Just above the base of a cat’s ears is a little space commonly known as Henry’s pocket. What is it for? Theories abound: It helps locate sounds. It enhances sounds. It adds more flexibility to better express emotion. It serves no purpose at all. Science simply hasn’t figured it out yet.

But ticks and fleas love Henry’s pocket, so if you have feline furry friends, be sure to inspect their pockets when checking for parasites!

Praying Mantis, the One-Eared Wonder

The praying mantis was long assumed to be deaf because it doesn’t make or respond to sounds. But in the 1980s, the one-millimeter-long slit in its chest was determined to be an ear with two eardrums that face each other. It’s an ultrasound receptor with one purpose — to detect bat attacks. When the insect, already tuned in to a hunting bat’s sonar, hears the telltale “feeding buzz,” it goes into a downward spiral, avoiding capture by milliseconds.

Barn Owls Can Hunt by Sound Alone

Barn owls are nocturnal hunters with excellent vision. But their hearing system is what truly sets them apart as hunters in the animal kingdom.

Their advantage comes from their facial disc. Many owls have a round, bowl-like face that, similar to the outer ear of a human, captures sound waves and funnels them toward the ear canal. But the barn owl’s facial disc is extra deep, like a satellite dish, so it collects and funnels sound waves especially well.

Barn owls have about the same hearing range as humans do, but they pick up far more nuance — like mouse paws on dirt — from far off, so they can locate prey by sound alone in complete darkness.

Beetles Live in a Silent World

Around 350,000 species of beetle currently walk the planet, but only a few species of scarab and tiger beetles have ears that allow them to receive and respond to airborne sound.

The other hundreds of thousands of beetle species can’t hear at all. Some can, however, learn and communicate by receiving and causing vibrations in whatever solid object they’re standing on or clinging to.

Some Frogs Are Available With Noise-Canceling

When a female American green treefrog (Hyla cinerea) wants to pick up on mating calls, she inflates her lungs. This makes her eardrums react less to unwanted sounds, like the mating calls of other species. It also lets her better tune in to mating calls from her species.

Per the authors who discovered this, it’s “a biological mechanism for noise cancellation that is functionally analogous to signal processing strategies implemented in noise-cancellation headphones.”

One Species of Mole Rat Evolved to Have Poor Hearing

Naked mole rats live their whole lives underground and depend on cooperation. Like bees, they live in colonies with soldiers, workers, a queen, and plenty of duties to coordinate. Their burrows are a cacophony of chirping and squeaking.

But surprising results from a 2020 study show that these mole rats are born with very poor hearing due to mutations in six hearing loss-related genes. Natural selection led them to develop poor hearing as a beneficial adaptation to their noisy environment!

How is your hearing these days? Contact us today if you or a loved one could use a hearing evaluation!