This is absolutely true: never keep you pug outside if you love him! Pugs cannot endure heat and high humidity well. Usually, to cool the body, dogsstick the tongue out and breathe intensively. If the tongue is small, the cooling area is small too and such dogs have a higher chance to overheat. This is exactly the case with pugs - their tongues are fairly small, and the dog can die in less than half an hour if left in a hot environment.