The Agnatha or “jawless fish” were once the planet Earth’s earliest and dominant vertebrates, appearing millions of years ago on a planet formerly ruled by tentacled mollusks and spiny arthropods. Today, the only living examples of these fishy forefathers are the scavenging “slime hags” (which are quite fascinating, but not haematophagous) and the sucker-faced “lampreys.” Many lamprey species are harmless filter feeders, but some varieties are famously parasitic. Latching on to other fish, they rasp through flesh until they reach blood or other bodily fluids, and may kill hosts that aren’t large enough to survive the loss. Though they seem primitive and vicious, lampreys are also dutiful mothers who migrate far to spawn and carefully stack stones into protective nests.
This tiny Amazonian relative of the catfish is widely infamous for its rare habit of swimming into the urethras of large mammals (such as humans) foolish enough to urinate in the river water. This is purely accidental (and fatal) on the Candiru’s part, as it mistakes the trail of urine for a stream of water from the gills of a bigger fish. Their thin, stunted bodies and tiny barbs are specially adapted for lodging in blood-rich gills, where they use their tiny jaws to nibble into a vessel and feast…the ticks of fish-kind.
3. Torpedo snails
Perhaps our most unlikely vampire, Cancellaria cooperi is a species of sea snail that preys almost solely on the blood of Torpediformes or “electric” rays. True to their name, these stingray cousins can deliver up to 220 volts to paralyze prey and predator alike, but parasites are another matter. The slow but persistent little snails can smell a Torpedo’s mucus coating from several feet away, and use a long, thin tube to siphon off blood without causing the fish any pain or discomfort.
2. Vampire Finches
The Galapagos islands are famously home to a wide array of tiny finches, closely related but adapted to the food sources of each island with their specialized beaks. None are perhaps so bizarre as Geospiza difficilis septentrionalis, the only bird known to regularly supplement its diet with fresh blood. It shares its somewhat desolate chunk of land with thousands of much larger boobies (the birds, dummy), who don’t even seem to resist as the relatively tiny finches peck gruesome little holes in their bodies. It has been theorized that the finches once plucked parasites from these birds, which would have developed an instinct to ignore the painful jabs for their own benefit. Finches who learned to lap up blood from the wounds for a little extra nourishment were probably better survivors as the island’s food dwindled, so they slowly shifted to vampirism and their victims had little means of catching on. To add insult to injury, the finches may also prey on booby eggs, pushing them out of their nests to break them open.
The Diptera or true flies include thousands of known species, and while most flies are harmless, cute little nectar-drinkers, beneficial scavengers or predators of other insects, the Diptera have also found more ways to suck blood than any other order in the animal kingdom. The females of some Culicidae – the infamous mosquitoes – use their syringe-like mouthparts to draw blood from mammals and transmit parasites that kill more human beings each year than all other natural forces combined. “Horseflies” are a little more crude, using razor-edged mouthparts to slice open flesh and lap up the blood that oozes out. Biting midges and gnats can be almost too tiny to notice until one feels dozens of prickly bites. More unusual are the Hippoboscidae or “louseflies,” some of which live their entire adult lives in the fur of their host and don’t even have any wings! There are even flies with bloodsucking larvae, like the “congo floor maggot;” these crawlers take a cue from bedbugs and drink the blood of sleeping victims with their leech-like mouths. One has to wonder why we associate Vampires so closely with bats…it would be so much more fitting if Dracula transformed into a bug-eyed, buzzing insect.