Photograph by Joel Sartore, Nat Geo Image Collection
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Bats of many species, including the common vampire bat, play host to blood-sucking parasites.

Photograph by Joel Sartore, Nat Geo Image Collection

The Vampires That Feed on Vampires

If vampire bats and blood-drinking moths are scary, meet their parasites.

Another Halloween is upon us, and that means stories about animals that poke you full of holes and eat your insides!

But this year, instead of looking upon these vampires in revulsion, perhaps we can find a little common ground. Even our most-hated blood-suckers are plagued by creatures that thirst for blood.

“Blood-feeding is a lifestyle which has evolved independently in many groups of animals,” says Tommy Leung, a parasitologist at the University of New England in Australia. Called hematophagy, eating blood is common, he notes, and “found in over fourteen thousand living animal species, even in groups that most people might not have suspected.”

Vampires on Vampires

Only three out of the nearly 1,400 known bat species are vampires. But did you know that even these species are preyed upon by blood-suckers?

Many bat species must contend with tiny, blood-feeding bat flies that can look like the face-huggers out of the Alien movies. Species of vampire bats, however, may have it worse than most.  

“Vampire bats have more parasites than the average bat,” says Gerald Carter, a bat biologist and postdoctoral researcher at the Smithsonian Tropical Research Institute in Panama.

Researchers in one study captured hundreds of specimens from 53 bat species to assess their prevalence of parasites. They found that two vampire bat species had some of the heaviest loads of bat flies. One particularly unfortunate common vampire bat was covered with 63 blood-sucking bat flies.

And these flies can be relentless.

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Engorged with human blood, this mosquito may itself become a meal for blood-sucking midges and bloodthirsty spiders.

In Belize, one of Carter’s colleagues studied the bats and their flies by marking both with tiny drops of paint. She released one bat with a marked fly and kept seeing the same fly return to her throughout the night, each time on a different, unmarked bat.

“Apparently, the released bat went back to the roost and the fly switched hosts,” says Carter.

Still not feeling bad for vampire bats? Imagine what it’s like having one or more of these little monsters crawling all over your body.

Beaks Built for Blood

An animal you probably don’t associate with Halloween is the finch—but maybe you should. One species native to Wolf Island in the Galapagos is known for its habit of pecking into the skin of larger birds and then lapping up the blood that pours out.

While the finch’s bloodletting looks positively grisly, this behavior is thought to help the birds survive times of extreme drought.

WATCH: These bloodthirsty ground finches feed on Galápagos seabirds.

Of course, even vampire finches probably suffer a little bloodsucking of their own. That’s because birds are a favorite meal for mosquitoes.

Vampire Hunters

Mosquitoes are surely one of the least pitiable creatures on earth. Not only do their bites make us itch, but these ubiquitous insects carry a host of diseases responsible for millions of deaths worldwide each year.

But even mosquitoes are not immune to a little blood loss.

Tiny insects called midges have been documented feeding on at least nineteen species of mosquito. Similar to the mosquitoes it parasitizes, the midge has sharp mouthparts called a proboscis. The midge uses its proboscis to stab into a mosquito’s engorged stomach and suck out recently ingested blood. In some cases, this can cause organ damage in the mosquito.

What’s more, scientists have found a species of jumping spider, Evarcha culicivora, that actively targets mosquitoes with a full belly.

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Bedbugs are known for parasitizing humans, but they can harbor pests, such as the protozoan Trypanosoma cruzi, which causes Chagas disease in humans.

But since the spiders target whole mosquitoes instead of just their blood, Leung says, “I guess you can say that E. culicivora is more like a vampire hunter rather than a vampire itself.”

Blood-sucking Moths

Many moths are fruit-eaters, or frugivores. They drill their mouthparts into the surface of a piece of fruit and then suck out the juices, not unlike a mosquito attacking a human.

One genus of moths called Calyptra, though, uses this fruit-feeding appendage for another purpose—drinking the blood of mammals such as tapirs, rhinos, and even humans. Jennifer Zaspel, a National Geographic grantee and director of the Purdue Entomological Research Collection, reported this behavior in 2008.

But before you start having nightmares about a blood-sucking Mothra, consider that moths and butterflies are more often the victims of hematophagy.

WATCH: Bloodsucking moths have been found in Siberia.

Lots of little critters suck the blood right out of the wings of butterflies and moths, notes Andy Warren, a moth and butterfly scientist and collections manager at the McGuire Center for Lepidoptera & Biodiversity at the Florida Museum of Natural History. This includes mites, flies, and tiny, parasitic wasps whose larvae eat lepidopterans from the inside out.

No parasites have yet been documented on blood-sucking moths, but “I guess it would only be poetic justice if they attacked Calyptra moths as well,” says Warren.

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WATCH: Think there's nothing scarier than a vampire bat? How about the bug that sucks its blood?