Out for Blood!

As we meander through the forest, studying small mammal movements and listening to songbird serenades, we are being hunted by creatures who want something we have, something necessary for their survival—our blood.

Michigan is a lovely state, with breathtaking leaf displays in autumn, peaceful waterfalls, and of course the majestic Great Lakes. Not exactly the setting you’d expect for a horror story starring blood-thirsty monsters. Yet an eight-hour day in the woods can easily yield a dozen painful bites from deer flies. A short walk into a swamp to find the massasauga rattlesnake requires suiting up in gear to prevent hundreds of mosquito bites. Any person near one of Michigan’s 11,000 lakes can count on a few bites from stable flies or black flies.

After every excursion, students must perform a “tick check” on themselves before settling in for the day. Sometimes dozens of ticks must be removed before they attach and begin feeding on the students and teachers. While most are harmless wood ticks, they nonetheless instill fear and discomfort in even the most rugged of students—and for good reason. This part of Michigan is home to blacklegged ticks that carry Lyme disease and lone star ticks that carry a disease that causes a potentially fatal allergy to red meat.

But ticks pale in comparison to the bloodsuckers that terrify students the most: leeches. The waters of some ponds and lakes are home to these fanged worms, many of which feed on blood. And if leeches weren’t bad enough, three species of blood-sucking lamprey feed on other fish in many of the rivers. No habitat in Northern Michigan is without its real-life vampires.

The more I learned about these creatures, the more I appreciated the finer points of their gory behaviors.

After my first year teaching the field course, I could think of nothing but joining the fight to eradicate these blood-thirsty pests and end their horrific story. But the more I learned about these creatures in my beautiful state of Michigan and other bloodsuckers like them around the world, the more I appreciated the finer points of their gory behaviors. Even these animals that have speciated with behaviors that inspire fear and transmit disease in our fallen world display the intricate design of the Creator.

Real-Life Vampires

Though we might call them vampires, scientists use the term hematophages to describe bloodsucking animals. Hematophagous animals are extraordinarily rare, making up fewer than 30,000—just 2%—of the 1.5 million described animal species. However, the feeding strategy is present in a large variety of animals worldwide, ranging from insects to vertebrates including mammals and birds. Most bloodsuckers (more than 14,000 species) are arthropods, animals with jointed legs and a hard exoskeleton. This includes at least 11 families of dipterans (flies and mosquitoes), 17 species of moths, 130 species of kissing bugs, 2 entire insect orders (sucking lice and fleas), 850 species of ticks, and other groups. Many of these arthropod species are obligate hematophages, meaning they must consume blood to survive and reproduce. In addition to arthropods, three quarters of the 1,000 leech species, approximately 20 lamprey species, 3 bat species, and 2 bird species are hematophagous.

Blood-Sucking Beginnings

It shouldn’t come as a surprise to find bloodsucking behavior in nature—animals will exploit any potential food item to make a living. However, it is difficult to think about animals feeding on blood as part of a creation that God would call “good.” Considering that most scientists, including secular scientists, believe blood-sucking strategies replaced plant eating (known as phytophagy), it seems reasonable to conclude that hematophagy resulted as a consequence of the destructive influences of humanity’s rebellion against God. The fall ushered forth many instances of animals feeding on other animals, including predation, parasitism, and blood-sucking. But just how long have these creatures been around?

Creation scientist Jeremy Blaschke suggests that the number of species in a parasitic group, called a lineage, may indicate when a group transitioned to parasitism (including blood-feeding). Groups containing fewer than 1,500 species recently transitioned to blood-feeding strategies (less than 4,000 years ago). Only a few hematophagous groups contain more than 1,500 species, including mosquitoes and fleas. However, the lack of any plant-feeding forms in a group suggests that the transition to blood-feeding happened early in the diversification, even before the flood (more than 4,500 years ago). In fact, we have found hundreds of examples of hematophagy in the fossil record, including a mosquito filled with blood. While many of the blood-sucking insect groups likely changed their menu from plants to blood prior to the flood, many other groups, including the 17 species of blood-feeding moths, 130 species of kissing bugs, the oxpecker and vampire finch, and the 3 species of vampire bat, likely developed their taste for blood several hundred years after the flood.

Art by Chris Neville

Left to right: mosquito, kissing bug, lamprey, vampire bat, tick

Built for a Blood Diet

God equipped hematophagous animals with incredible features that enable them to feed primarily or even exclusively on blood. For example, the mosquito’s needle-like mouthpart (proboscis) is actually six individual needles that all pierce the skin and help draw in the nourishment. Though mosquitoes initially used these mouthparts to feed exclusively on fluids within plant tissues, female mosquitos now use these needles to draw a blood meal from vertebrates.

Even more horrific than the mosquito’s needle mouth, the lamprey’s teeth don’t just cut through the scales of fish; they also help keep the lamprey attached to its host. Meanwhile, a dose of anticoagulant keeps the fish’s blood flowing. While we don’t know what lampreys ate before the fall, their teeth enable them to now efficiently feed on other fish.

Speaking of scary teeth, horseflies have serrated jaws that slice through the flesh of unsuspecting creatures. They even use their jaw muscles to enlarge the wound while lapping up the warm meal.

The variety of structures used to suck blood directly out of veins or cause it to pool on the surface is rivaled only by behavioral features used to find a host. Unlike eating plants, feeding on animals requires hunting behaviors. Some bloodsuckers, like the bed bug, meet this challenge by living where the host sleeps and hiding out during the day. (Don’t let the bed bugs bite, indeed.) Others like hard-bodied ticks find a nice blade of grass and wait for the unsuspecting host to pass by. Still others, like mosquitoes and tsetse flies, will fly for kilometers hunting a host. And because they feed mostly on sleeping prey, vampire bats can search for just the right place to bite, using their heat-sensitive, fleshy noses to locate where blood flows closest to the skin’s surface.

In addition to new uses for their physical features after the fall, some behavioral changes enabled animals to shift to a new lifestyle. Most predatory animals don’t try to feed on prey 35 million times the size of their own body. This would be like a lion trying to eat an animal the size of a small mountain. But some bloodsuckers take on the challenge, risking the wrath of an enormous host that likes to defend itself. To minimize the risk of being swatted or squashed, mosquitoes call off the hunt when they’re full, and other bloodsuckers, like the kissing bug, give their host a little anesthetic to avoid being noticed when they bite.

A Blood Buffet

Because of the peril intrinsic to accessing a blood buffet, some of these animals load up while they have a chance. For example, a kissing bug can gulp down 10 times its weight in blood in just one minute.

Most animals become ill after consuming a small amount of blood, yet hematophagous animals gulp it down without negative effects. Turns out, feeding primarily or even exclusively on blood provides both too much and too little of some materials. Blood is a great source of protein, but it also gives the animal toxic levels of iron. With too much iron, the bloodsuckers get far too little fat and almost no B vitamins. It’s a blessing for these bloodsuckers that God gave them the metabolism for feeding on an iron-rich diet, even iron-rich plants like legumes before the fall.

Once again, God has provided for their nutrition. What nutrients some bloodsuckers can’t get from their food, they get from symbiotic bacteria in their gut. Perhaps originally, before these animals developed their blood-sucking behavior, the bacteria helped these creatures digest a diverse diet. This relationship continued to preserve the animals as they shifted to their current bloody diet that is difficult to digest.

Our Perspective and Their Purpose

When you’re warding off horseflies, picking ticks off your dog, swatting at mosquitoes, or combing through hair for lice, it can be easy to wish that we could eradicate these pests. However, it’s important to remember that all species, even those that diversified with post-fall adaptations, demonstrate the Creator’s handiwork.

Even these bloodsuckers play a role in creation’s delicate network of interconnected species. More species make for more stable ecosystems with more connections. Some other creatures are always relying on blood-sucking species. For example, mosquitoes, flies, and ticks are an important food source for animals such as bats, birds, opossums, and frogs. Some bloodsuckers also pollinate plants. And doctors even use leech therapy to restore circulation when they reattach body parts like fingers or lips.

However, we must be prudent when it comes to stewarding these creatures. While the overwhelming majority only cause minor physical discomfort, some bloodsuckers are the most dangerous animals on the planet. The kissing bug transmits the deadly Chagas disease caused by a Trypanosoma parasite. In sub-Saharan Africa, the tsetse fly transmits African Sleeping Sickness caused by another species of Trypanosoma. Fleas transmit Yersinia pestis that causes plague. But the mosquito is the most prodigious killer of all, each year transmitting dozens of diseases around the world, including malaria caused by Plasmodium parasites, and killing hundreds of thousands of people where insecticides are not used.

Proper stewardship requires preventative measures and creative solutions. For example, a team of researchers from NASA and Old Dominion University have developed a robot that attracts and kills ticks in areas where humans encounter these blood-suckers. And recently, the state of Florida received permission to release genetically modified mosquitoes into the wild. The female offspring of these mosquitoes die in the larval stage before they can hatch. Since only female mosquitos bite, scientists hope to control the spread of disease such as Zika virus in humans and heartworms in dogs.

Not a Horror Story

My treks through the woods no longer feel like a horror story. While I don’t love being on the menu, I’ve learned that these blood-thirsty animals are intricately equipped by a Creator who allowed these creatures to adapt to the fallen world. Our rebellion against the Creator has contributed to a breakdown in his good creation, yet nature’s vampires still declare God’s eternal power and divine nature. He called his creation “good” during creation week and will one day redeem all aspects of creation through his redemptive plan on the new earth. Even the vampires will one day be very good again.