Am I the only pet owner who's tried to shove a bowl of water under my pup's dangling tongue . . . only to have him turn his nose up at it? I didn't always realize that just because his tongue was out, didn't mean he wanted a drink. Dogs hang their tongues out when they are hot (sometimes they're also thirsty), but it's actually a way to cool themselves off. Typically, pups pant and breathe in air through their noses and release the air through their mouth – when the mouth's open, the saliva can evaporate, producing a cooling effect! So, if your choosy pooch doesn't choose water when he's outside like Samson [1] here, just know his body's working to further cool down his blood flow just by that cute technique.