The consumption of blood is scientifically known as haematophagy, and an organism that feeds partially or exclusively on blood is haematophagous. As non-parasitic omnivores, it’s easy for us humans to vilify this seemingly alien lifestyle, but consider the fact that many other creatures, including ourselves, are constantly forced to kill to survive. The animals you’re about to meet might seem sneaky, creepy or even cruel, but these are animals who have adapted to feed on other creatures without normally killing them. Rationally speaking, running off with a little blood is a lot less destructive and efficient than ripping the legs off an antelope.
While there are various insects that feed on blood, fleas are the largest group to be 100% haematophagous, with over 2000 known species heavily adapted to live off the blood of mammals. Their flexible, densely armored yet paper-thin bodies are perfect for “swimming” quickly through thick fur, resisting the host’s attempts to claw or bite them out. Fleas never have wings (which would slow them down on their hosts) but compensate with incredible “spring loaded” legs, allowing them to leap over 200 times their body length to come and go from hosts. They begin their lives as maggot-like larvae, which do not bite but feed on debris such as dead skin, hair, feathers or even their parent’s waste. Yes, mommy flea will not only drink your blood, but poop it into her babies. At least it’s going to use, right?
While most fleas are happy to eat and run, some species are known as “sticktight” fleas for the female’s rather unpleasant feeding method; she embeds her entire body deep under the host skin, swells up to the size of a pea, lays her eggs and dies, still embedded in the flesh where she may cause a bacterial infection. Fleas are not to be confused with ticks, who were just barely pushed off this list. Ticks are actually eight-legged arachnids, and the largest of all mites.
The term “bug” originally referred only to insects of the order Hemiptera, which includes the stinkbugs, assassin bugs, waterbugs, aphids, cicadas and many others. Most bugs are harmless, but the notorious “bedbugs” are among the few parasitic varieties. True to their name, these wingless creatures hide in the nesting materials of larger vertebrates (such as your mattress and pillows) to feed on the blood of hosts as they sleep. Extremely resilient, they adapt quickly to diseases and pesticides, making them extremely difficult to exterminate. This rapid adaptation is due in part to their harsh reproductive habits; in order to mate, the male must overpower the larger, tougher female to stab through her exoskeleton with his bladed genitalia, and the female must be strong enough to survive these wounds to lay her eggs, meaning only the toughest of both sexes will pass on their genes. In some exotic species, the female even has a bladed phallus of her own, making bedbug sex a violent fencing match.
Related to earthworms and other Annelids, leeches can be found around the world on both land and in the water. Most species are carnivorous, preying on smaller invertebrates or even the eggs of fish and frogs, but the famous haematophagous leeches are armed with circular, saw-like teeth and anaesthetic, anticoagulant compounds in their saliva, allowing them to make a tiny, painless incision on their host that gushes blood for hours. In the dark ages, it was believed that leeches could treat almost any illness by removing excess or “bad” blood, and while we now know this was never true, their efficiency at draining blood is still of great interest to medical science, and leeches have even been used to remove dangerous clots in reattached limbs. More complex than you probably thought, leeches possess multiple hearts, multiple brains and in some species a cluster of tiny eyes. Many species even keep close watch over their young, fashioning a protective cocoon around the eggs and carrying the tiny babies on their backs until they can fend for themselves.
7. Vampire moths
Most moths and butterflies either feed on nectar or never even feed at all, living only long enough to mate. At least one moth, however, uses its sharp proboscis to drill through the skin of mammals and gorge itself on blood. As the host’s blood flows through the straw-like mouthparts, it causes tiny barbs to raise and anchor in the flesh until feeding is complete. In a reversal of mosquitoes, only the male moth is the vampire – he makes good use of the alternative energy source, since female moths spend most of their time resting and waiting while the males are left to search far and wide for a mate.
6. Vampire Bats
The most famous of all blood drinkers and arguably the only parasitic mammal, there are only three species of vampire bats or Desmodontidae, all native to the Americas. They are the only bats adapted to comfortably walk and even hop on the ground, allowing them to land near larger sleeping animals and creep up on them. Their delicate, razor sharp teeth make a tiny incision in the host flesh with little to no pain, and their anticoagulant saliva keeps the blood flowing freely as they lap it up. While almost all bats are communal, vampires are the only bats known to care for one another’s pups, even taking in orphaned young as their own.
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. photo: omeuceu
By Jonathan Wojcik/bogleech.com