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Why cats have a secret ear pocket

10/9/2025

Translation: Eva Francis

Cats are full of surprises – even their ears hide a little secret pocket. But what’s it for? Let’s find out.

«The smallest feline is a masterpiece.» Leonardo da Vinci’s words keep popping into my head as I marvel at my cats as if they were precious artworks. The other day, I noticed a detail I’d never seen before – the pockets on the sides of their ears.

«What are they for?» I ask myself, briefly considering whether they might be suitable for hiding snacks. Probably not. So I decided to find the actual answer.

Who’s Henry?

I quickly discover this fold of skin has a name: Henry’s pocket. The term first appeared in a natural history book in 1971. According to one theory, it could have been named after Joseph Henry. The US physicist carried out research on electromagnetism and sound waves.

Physicist Joseph Henry: are Henry’s pockets named after him?.
Source: Everett Collection/Shutterstock

Hunting support

Joseph Henry’s topics of research are indeed related to this secret pocket on a cat’s ear. One of the most common theories (link in German) is that the fold of skin weakens lower tones when the ear is angled. For predators, this is helpful when hunting, as it allows them to hear high-frequency sounds from small prey more clearly. However, there’s no scientific evidence to support this theory.

Another possible but unproven theory is that the fold of skin allows the ear to move more freely. More specifically, Henry’s pocket could allow cats’ ears to bend and rotate better. This could be useful when hunting, as it means they can run in one direction and listen in another. This would allow cats to locate their prey more accurately.

Do Henry’s pockets help cats while hunting? It’s scientifically proven, but there are indications that they do.
Source: vvvita/Shutterstock

What’s unlikely is that Henry’s pockets are useless and just a relic from ancestors. Why? Because lots of animals with skin folds on their ears have great hearing – weasels, bats, some primates, and dogs, for instance.

A nest for parasites

Whichever function Henry’s pockets may have, pet owners should keep a close eye on them. Parasites such as fleas, mites and ticks love to nest in these narrow hiding places. That’s why you should check them regularly and clean them gently (or have them cleaned). Turns out I’m doing the right thing when I marvel at my cats as if they were precious artworks.

What cat mystery do you find most fascinating? Let me know in the comments.

Header image: Darina Schweizer

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Darina Schweizer

Senior Editor

Darina.Schweizer@digitecgalaxus.ch

I like anything that has four legs or roots. The books I enjoy let me peer into the abyss of the human psyche. Unlike those wretched mountains that are forever blocking the view – especially of the sea. Lighthouses are a great place for getting some fresh air too, you know?

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