Common vampire bats (Desmodus rotundus) are found only in Latin America. They appear to have been rare prior to the arrival of modern humans who brought livestock that these bats now feed on. Though they have become a problem for ranchers, vampire saliva has been termed a "treasure trove" of molecules that one day may be used to save human lives. They are highly social animals that adopt orphans and share meals with those less fortunate. Vampire Bats, Roosting