Taste responsiveness to food-associated acids in the squirrel monkey (Saimiri sciureus)

The taste responsiveness of six adult squirrel monkeys to five food-associa ted acids was assessed in two-bottle preference tests of brief duration (5 min). In experiment 1 the monkeys were given the choice between tap water a nd defined concentrations of citric acid, ascorbic acid, malic acid, acetic acid, or tannic acid dissolved in tap water. In experiment 2 the animals w ere given the choice between a 50 mM sucrose solution and defined concentra tions of the same acids dissolved in a 50 mM sucrose solution. With both pr ocedures Saimiri sciureus significantly discriminated concentrations as low as 10 mM ascorbic acid and acetic acid, 5 mM citric acid and malic acid, a nd 0.2 mM tannic acid from the alternative stimulus. The results showed: (1 ) that squirrel monkeys respond to the same range of acid concentrations as other nonhuman primate species tested so far, (2) that Saimiri sciureus de tects food-associated acids at concentrations well below those present in m ost fruits, and (3) that the responsiveness of this New World primate to ac idic tastants was largely unaffected by the addition of a sweet-tasting sub stance. The results support the assumption that squirrel monkeys may use so urness and/or astringency of food-associated acids as a criterion for food selection.