Even if you haven’t spent a ton of time around horses in your life, there’s a good chance you’ve noticed a spot on their legs that looks like it could use some serious lotion.

Maybe a whole day at the spa.

The crusty brown spots you seen on their legs are affectionately termed “horse chestnuts,” and are totally harmless.

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They’re thought to be leftovers from horses’ five-toed ancestors, though no one is totally sure.

Another idea is that they could be the vestigial remains of a scent gland.

Oh, and back in the day they were referred to as “night eyes,” and people thought they helped the animals see in the dark.

The growths can develop on the front and/or back legs and usually start off small, growing in size until they’re easily (and painlessly) peeled away.

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They’re not a concern for horse or owner, though perhaps they could be to the dogs on the premises, because the morsels are sometimes tossed into their food dishes.

But that’s a story for another day.