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Hey, welcome to Stuff to Blow Your Mind.

My name is Robert Lamb.

And I'm Joe McCormick, and we're back with part two in our series on urine-based communication in animals.

In part one, we introduced the idea that while humans have an almost infinitely expanding arsenal of tools and skills and tricks for sharing information with

one another. One medium that we don't use, or at least don't use very much, but which is used

throughout the animal kingdom is urine. So in part one, we also talked about a story that,

the story that initially got me interested in covering this on

the show, which was a recent paper documenting a behavior in Amazon River dolphins called

aerial urination, uh, which goes like this. One male dolphin floats upside down and urinates

in a stream up in the air over the water. And then usually another male dolphin seeks seeks out the stream, swims over, and puts its face right into the pea fountain.

It's not yet known why the dolphins do this, but the researchers who wrote the paper proposed that it is a form of communication, its information sharing between male dolphins to sort of give a fact sheet about the originator of the urine stream.

Kind of have a look at my medical chart here.

You can sense my urine with the whiskers on your snout and get a sense of me.

And of course, we talked also about how urine can convey lots of different kinds of information about physical health, social dominance, and things like that.

And those pieces of information are useful for male dolphins to share with one another because it helps them make decisions about whether to challenge each other for access to food resources or mates.

We also talked more generally about what urine is and is not, and what kind of information it contains to a fluent reader.

We also went on some other interesting tangents, for example, about why so many animals actually have voluntary control over urination in the first place. Why can they actually decide when they want to release the urine? We talked about how urination actually can be thought of as a kind of social behavior in humans and a bunch of other things.

And we're back today to talk more about pee-based communication.

Yeah, yeah. Like in general, there's just a lot of information in urine.

But as humans, we cannot pick up on most of it via our own senses.

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