Verified answer

Evaporative water loss isn't the only strategy an animal might have in this situation. They could press against a cooler substrate thus maintaining a lower body temperature. And of course, they could go into burrows where the surrounding soil temperature could be much lower than 40 C.

Water evaproation is going to happen no matter the Humidity factor in sunlight ,

Or at night and its still hot, water still evaporates , but slower .

All surace water on earth is in a constant state of flux between vapor and liquid when that water is at the surface between the air and skin, or land, or body of water. Surface water evaporates .

If the air was so saturated and could not take in anymore water vapor , you would sufocate .

In Steam sonas a few people Have passed out because the air was so saturated with steam ( water vapor) it displaced enough air to make people actually pass out . This is an extreeme case . Dense fog is water vapor and maybe the most water vapor content in air you will ever encounter naturally . Some say they can "feel' it and makes breathing seem slightly difficult . I have never experainced this though.

A few simple ways is get a cooling scarf, or an Ice neck pad. The scarf uses a chemical reaction that when wet becomes cold, and around your neck it cools the blood in the carotid arteries. The ice neck pad, which is a tube like filled with a gel, and attached to a flecks wire, and rap it around your neck. Does also the same as the scarf. In a HEAT emergency, put ice packs in the armpits, and groin area. And of course around the neck. For a short duration you can cool off also by putting something cold, like and ice oack, or even frozen meat or veggies ubder your arm.

i don't think that case would ever be reached, but the question is interesting

i don't know, perhaps in that case the body wouldn't be able to maintain homeostasis

-By "Doing"- as LITTLE as Possible... ;)