Five rhesus monkeys (Macaca mulatto) were placed on a low-sodium diet and given injections of furosemide in order to promote sodium loss. The results indicated that these methods elicit a substantial and specific salt hunger. Issues surounding salt hunger are discussed.Comparative evidence in a wide variety of animals suggests the existence of special behavioral mechanisms that mediate sodium homeostasis. Rats display an innate hunger for salt the first time they are deprived of it (Nachman & Cole, 1971;Wolf, 1969). In addition, it has been demonstrated that rats remember the location of salt solutions that they encountered when sodium replete and return there when they are salt hungry (Krieckhaus, 1970). Moreover, the rat's hedonic response to a salty taste varies as a function of its internal state. When the rat is sodium deficient, very salty tastes are perceived as pleasant. When it is sodium replete, very salty tastes are unpleasant. This hedonic shift has been shown to be operative in the rat the first time it is made salt hungry (Berridge, Flynn, Schulkin, & Grill, 1984). Sheep, also have an innate salt hunger which is expressed when the salts in the soil of a grazing area are periodically washed out by rain . Similarly, mountain gorillas may seek salt when their regular diet is low in sodium (Schaller, 1963). There is also evidence that humans display a hunger for salt when they are deprived of sodium (McCance, 1936;Richter, 1956) Moreover, the hedonic perception of salt by humans changes following dietary sodium deprivation (Bertino, Beduchamp, & Engelman, 1982;Bertino, Beauchamp, Riskey, & Engelman, 1981).The evidence, when taken together, suggests that behavioral mechanisms for sodium homeostasis are found in many species, including primates. Therefore it is noteworthy that a recent study (McMurray & Snowdon, 1977) did not find an increased appetite for salt in rhesus
