In the 2008 film “Twilight,” a vampire describes the scent of blood as being “like a drug.” While in the world of fantasy, vampires may crave blood for reasons that are tinged with the erotic or infused with the demonic (such as in the 1922 movie “Nosferatu”), real life vampires actually exist in nature. Many real-life animals known as hematophages that sustain themselves on blood for a more practical reason — survival.
Some hematophages are well-known: For example, vampire bats in the subfamily Desmodontinae helped inspire the legendary monsters that bear their name and no one can forget blood-sucking mosquitoes and leeches. Many are also familiar with bloodsuckers that don’t target humans, such as lampreys (Petromyzontiformes), which live very deep in lakes and attach themselves to the sides of fishes with their strange, biting mouths.
Related
There are other, more obscure hematophages, signifying that vampiric behavior is something that evolved multiple times for a reason. Take the aptly-named vampire moths (Calyptra thalictri) which slurp blood in part so males can pass the salts onto females during mating. Vampire ground finches (Geospiza difficilis septentrionalis), despite preferring seeds and insects, will resort to feasting on the blood of other birds if conditions are particularly harsh. Meanwhile the leafhopper assassin bug (Zelus renardii) will hunt by impaling their prey on their tubular mouthparts, then sucking their innards out like a milkshake.
Vampire moth butterfly (Calpe capucina or Calyptra thalictri), Noctuidae. (Photo by DeAgostini/Getty Images)While these creatures are seemingly vastly different from each other,........