Morphological, Anatomical, and Physiological Signs of Senescence in the Great Fruit-Eating Bat (Artibeus lituratus)

Abstract

The longevity of bats is longer than expected based on their small body sizes and high metabolic rate. However, signs of senescence have been poorly studied for free-living bats, especially for Neotropical species, because elderly individuals are challenging to find in the wild, and long-term mark-recapture studies are lacking. Here, we present the first record of a free-living Neotropical frugivorous bat, a female Artibeus lituratus (family Phyllostomidae), with impressive signs of senescence. We compare the elderly bat with conspecific juveniles and non-elderly adults morphologically, anatomically, and physiologically. The most noticeable signs of senescence were a significant loss of fur, dark spots on the skin, excessive dental wear, and reduced ability to assimilate sugar. These traits indicate that bats' challenges as they get old can be associated with reduced thermal insulation, ability to chew, and nutrient assimilation. However, by reducing extrinsic causes of mortality, flying capability in old bats with clear signs of senescence may represent a vital survival trait associated with the long lifespan of these animals.