Binturongs Smell Like Hot, Buttery Popcorn — Now We Know Why

The binturong's a curious animal, and looks something like a cross between a raccoon and a teddy bear. But one of its most striking features is what it smells like — people often say it evokes memories of hot, buttered popcorn.

Imagine machete-hacking your way through the rainforests of Southeast Asia, when all of a sudden, you get a whiff of... a movie theater? Scientists have looked into why this shy, secretive Southeast Asian animal also called the bearcat emits such a strikingly odd smell, but prior investigations into the scent glands of the binturong (Arctictis binturong) turned up empty handed — though uniquely smelly handed, we assume.

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Binturongs are distant relatives of cats, part of a family of mammals called vivvirids, which also includes the civet. It has a solid body and bushy tail — and then there's that smell. According to a new study in the journal The Science of Nature, we've discovered just why these jungle creatures smell the way they do — and past researchers looking at the scent gland, located just under the binturong's tail, were in the right neighborhood, but just needed to knock a few doors down. The binturong smells like buttery, delicious popcorn because of a chemical in its urine.

When binturongs pee, they squat, and the urine soaks their feet and tails. This allows them to create a scent trail whenever they move through the rainforests they call home, marking their territory and signaling their locations to other binturongs. Their urine contains the chemical 2-acetyl-1-pyrroline (2-AP), and it's the same compound created in the popcorn-popping process when sugars and amino acids interact. You'll also find 2-AP in freshly toasted bread, or cooked rice.

"If you were to make this compound, you would have to use temperatures above what most animals can achieve physiologically," said Christine Drea, a professor of evolutionary anthropology at Duke who led the study, in a press release. "How does this animal make a cooking smell, but without cooking?"

The researchers thought that perhaps it was something to do with what the bearcats ate — think of your own experiences with asparagus, perhaps — but weren't able to identify any single source. Their current best guess is that the 2-AP is produced when bearcat pee comes into contact with gut bacteria or microorganisms living on binturong skin.

But hey, the bearcat's a cousin of the poop-coffee civet, so who knows. There's apparently all kinds of magic happening inside the guts of Southeast Asian furbeasts.

Now That's Interesting

Many dog owners have thought their pets' feet smell like popcorn, or even corn chips. The "Frito foot" phenomenon can be due to Proteus bacteria, Pseudomonas bacteria or yeast living harmlessly on the dogs' feet.

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