The segment in which an M-for-L mutation is found is in the sixth transmembrane segment of domain one (DIS6) and begins NQAT in most Nav1s. (In Nav1.4, glutamate replaces glutamine, thus NEAT.) Criteria for the selection of hibernators are provided in Materials and methods. Briefly, nonhibernators resist lowering of body temperature below 30°C in a cold environment by increasing heat production and insulation. Hibernators listed in the table in low ambient temperature and under appropriate circumstances, specific to the species, allow or even promote a decrease in core temperature to below 10°C and to as low as 0°C and regulate temperature and respiration at that low temperature for days or weeks. Dashed lines indicate that no sequence was available in the NCBI database. In the headings of each column, gene names are shown above protein identities.