When minerals are deficient in the diet, animals often seek out concentrated sources of essential nutrients to relieve deficiencies. In this study, we documented fruit bat (Pteropus tonganus) preference or avoidance of calcium-rich fruits and use of commercial calcium blocks to obtain additional calcium. Individual captive wild-caught bats were videotaped nightly to document food choice, and results were compared to the nutritional content of the given fruits. Low-calcium, high-sugar fruits were the most preferred by bats of both sexes. Overall, sugar appears to be the primary basis for fruit selection, but sex differences in calcium block use suggest that females also may forage to relieve calcium deficiencies incurred by pregnancy and lactation.