Castoreum, a popular natural flavoring ingredient, is taken from Beaver anal glands!

Well, you all probably knew that beavers’ anal glands are natural, but it did ever cross your mind that they could be used in flavoring? Well, it turns that they’re used more commonly than you’d like to believe. For years, food companies have been using “castoreum” to flavor ice cream and other foods that need that rich, vanilla-like flavor. 

However, “castoreum” just a more pleasant and discrete word for a compound extracted from the crushed anal glands of beavers. Under FDA rules, companies are free to keep this ingredient a secret. Rather than including “castoreum” on the ingredients list, companies can just write “natural flavoring.” This makes perfect marketing sense; how many of you would buy that extra-large tub of vanilla ice-cream if you knew there were bits of beaver butt in it?

(Source)