Some species of birds like to rub themselves with ants (2017)

> This theory posits that the formic acid produced by ants might act as a sort of stimulant for birds, and might even be addictive.

I like that idea. I also remember growing up we used to put straw on top of ant hills waiting for ants to "attack it" with formic acid, then we'd lick the straw. It was a fun sour taste. Since birds groom their feathers, maybe they just enjoy it like kids might enjoy sour candy.

My dog used to rub himself on earthworms he found in the lawn. Very strange. I thought maybe since earthworms have high antifungal and and antibacterial properties, he was trying to medicate himself? Ants have similar properties.