If you like premium perfumes, this video is probably not for you.

Because, ahem, it explains how whale poop contributes to perfumes, and the story isn’t pretty.

Perfume-makers have used a substance called ambergris in their formulas for centuries. It’s rare, but it’s a bit gross when it comes to appearance, and it gives fragrances a long-lasting animalistic odour.

Although people have often discovered chunks of ambergris on the surface of the ocean or on seashores, for a long time no one was sure of their source. The assumption was that it was tree sap, or perhaps an odd undersea mushroom – or something else altogether.

But this ingredient of perfume is – look away – whale poop. Specifically, the poop of sperm whales.

When sperm whales wolf down squids, they are usually able to vomit the hard parts back out while the rest of the cephalopods are digested. But sometimes, the hard, pokey parts manage to make their way into the whale’s intestines.

Of course, some of these still manage to be ejected along with the whale’s liquid poop, sometimes these hard hard parts get entangled with one another, and with dead intestinal worms, to form a lump.

The result? Poop-collecting rectal roadblocks that are full of bacteria. Now, as the whale’s intestinal walls contract, some of these lumps break free, but the others get denser and progressively larger. A sperm whale’s colon can expand and deal with these situations reasonably well, but after a point, it eventually ruptures, killing the whale.

A huge butt-pearl of ambergris then floats to the surface of the ocean. To reach great perfume quality, this ambergris must bob along for a long time (months or even years) and react with the elements to transform into an expensive ingredient of eau de toilette.

However, not all perfume makers use ambergris because it is hard to find and incredibly expensive. In fact, it is illegal to use ambergris in perfumes in the US because the sperm whale is an endangered species.

There are alternatives available, such as synthetic ambergris made in laboratories. However, there are a few people who still prefer using whale poop to make them smell good.