Human shaped vampires pale considerably when compared to the real thing: vampire bats. Now, most bats eat insects, including mosquitoes, or fruit. They are beneficial and should be left alone. In Mexico, Central America and South America, however, there live bats that drink the blood from mammals.
Vampire bats have very sharp teeth. So sharp, in fact, that their victim rarely feels the bite. The saliva contains an anticoagulant which keeps the blood flowing as the bat laps it up. One bat doesn't eat so much, but bites day after day can kill cattle, as can multiple bites in one night as other bats sample the treat.
There is also the worry about rabies and other diseases. Most bats do not have rabies, but there is always a chance that a bite from one of these bats could transmit the disease.
So, human vampires kill or turn their victims into vampires. Vampire bats, on the other hand, sip blood and politely leave the human alive, provided they have not been given rabies. Dying of rabies is much worse than anything a human vampire can do to a victim. Oh, and vampire bats can fly, are intelligent, and keep themselves meticulously groomed. I am not much for either type of vampire but I think the bats won hands, er wings, down.