Humans sometimes choose to sit in a sauna for relaxation and arguably health benefits. If you lock humans at random in a sauna the first will be dead within minutes and most will be dead after a few hours.
Similarly, some humans will choose to take a cold shower or swim in a cold river etc, but if you force people into those temperatures some will die very quickly and most will die within minutes/hours, including most of the ones who choose to do it for periods of time comfortable to them.
In either scenario, even though we're all the same species, some humans will die within minutes and some may be able to survive days or even indefinitely at the same temperatures. Animals vary between individuals too, and commonly, reptiles will choose to bask right at the upper end of their own temperature limit, which will be different from the limit of other members of their same species.
It's also different for the same individuals at different times. If I tried to sleep naked in temperatures a little below 0, I would die rather than wake up, but if I was running, I wouldn't find that temperature unpleasant. Reptiles have radical changes in their metabolic rates at different times, far beyond the level of difference humans experience.
There's a huge difference between having access to something and sometimes using it by choice, and that situation being safe to force all individuals of a species into.
Absolutely, snakes will sometimes choose to bask in temperatures in excess of 40 degrees, but you can also kill snakes of the same species under 40 degrees in fairly short periods of time. You need to be very careful when interpreting the thermal needs and tolerances of animals, particularly reptiles, particularly snakes.
