The rate at which an animal looses heat to its surroundings is also governed by Newton's law of cooling (see question 26). The rate at which an animal generates heat is governed by its activity, but for a mammal cannot fall below its BMR. Most mammals must maintain their core (interior) body temperature at a steady value in the region of 37 C. They do this by balancing heat generation against heat losses. A variety of strategies are employed, for example sweating to increase heat loss.