This little goat is in a pen. noun. The definition of a pen is a small yard or animal enclosure, or an tool used to draw or write with ink. An example of a pen is a petting zoo. An example of a pen is a ball point.
If you are referring to the internal temperature of the human body, studies show most bodies can only survive up to 108 degrees Fahrenheit, or 42 degrees Celcius, as the proteins inside the body begin to die at around 105F.
This does not mean that reptiles can survive in any temperatures, their bodily functions still have to operate within an optimum range of body temperature and if the environment is too hot (certainly over 36 degrees C) or too low (below 4 degrees C) it can be fatal.