Comparative Nutritional Ecology of Two Genera of Vampire Bats: Desmodus Rotundus and Diaemus Youngi

Chemical and amino acid analyses of carcasses and blood diets were conducted for the first time, and significant differences between mammalian and avian blood as a food source were confirmed. Desmodus exhibited physiological constraint to mammalian blood through lower retention efficiencies and reduced fitness on the avian blood diet. Similarly, Diaemus was more efficient on its native avian versus mammalian blood diet. The physiological mechanism of resource partitioning by Desmodus was efficient use of relatively high concentrations of dry matter and crude protein in mammalian blood, and the inability to utilize fat. In contrast, Diaemus met almost half its energy requirement from fat in the dilute avian diet but was less efficient on the bulky mammalian diet. Vampire bats are therefore physiologically adapted to a specific host, selecting not only the package (mammals versus birds), but what is in the package (blood type).