Efficiency of food utilization by fruit bats.

Neotropical fruit bats consume figs (Ficus spp.) and other fruit in small bites which they suck dry and drop as pellets. The swallowed juice transits the short digestive system in 0.5 h or less. The efficiency of this unusual mode of feeding was determined by comparing the nutritional content of pellets, feces and urine of captive Artibeus jamaicensis to that of the wild figs (Ficus insipida) they had been fed. The bats extracted 57% of the wet weight and 37% of the dry weight of the fruit. The swallowed juice contained 40% of the non-fiber carbohydrate present in whole figs and was digested almost completely. Of the 160±37 seeds per fig, roughly 80% were swallowed, but almost all of these were passed intact in the feces. Overall 25-30% of the metabolizable calories in the figs were swallowed and absorbed. This mode of feeding enables the bats to extract the readily digestable calories from up to 2x their 50 g body weights in figs each night while never having to fly with more than a few grams of food in their guts at any one time.