In the world of nature, some animals aren’t just controlled by instincts or their environment, they’re manipulated by parasites in ways that almost seem straight out of a horror movie.
From ants whose bodies are hijacked by mind-controlling fungi to snails turned into zombies by parasitic worms, these creatures show just how deeply parasites can influence their hosts.
The phenomenon of “zombification” is a real and eerie part of the animal kingdom, with parasites using mind control to alter behaviour, drive them to danger, and sometimes even control their bodies to further the parasite’s life cycle.
This article is for general knowledge only and is based on information from online sources. Parasite-induced behaviours can vary by species and environmental factors. The studies mentioned are based on laboratory research, but parasitic control in the wild is often more complex and nuanced. Photos are for illustrative purposes only.
1. The Ophiocordyceps Fungus And The Zombie Ant
Perhaps the most famous example of parasitic zombification, the Ophiocordyceps fungus takes control of carpenter ants in the Amazon. After the ant becomes infected with the fungal spores, the fungus manipulates the ant’s brain, forcing it to leave its colony and climb vegetation.
Once there, the ant clamps onto a leaf or twig with its jaws, and the fungus kills it, using its body as a breeding ground. The fungal stalk erupts from the ant’s head, releasing spores to infect new victims below. This cycle repeats endlessly in tropical forests.
2. Hairworms And Grasshoppers
Hairworms, long, parasitic worms, manipulate grasshoppers and crickets in a way that’s almost too bizarre to believe. The worms infect the insects, growing inside them before taking control of their central nervous system.
The grasshopper is then compelled to leap into water, where the worm bursts from its body and continues its life cycle. Scientists believe the parasite alters neurotransmitters, creating an irresistible urge for water. The host drowns while the hairworm swims away, completing its transformation into adulthood.
3. Toxoplasma Gondii And Mice
Toxoplasma gondii, a parasite commonly found in cats, is known for manipulating the behaviour of infected mice. It alters the rodents’ brain chemistry, making them less fearful of predators, particularly cats.
The infected mice are drawn to cat urine, increasing their chances of being eaten by a cat, where the parasite can then reproduce. This makes them unwitting accomplices in the parasite’s life cycle. Research shows the parasite forms cysts in the brain, changing neural pathways related to fear and attraction.
4. The Lancet Liver Fluke And Ants
The Lancet liver fluke, a parasitic worm, has a strange way of ensuring its survival. It begins its life inside a snail and eventually infects ants. Once inside, the fluke controls the ant’s behaviour, forcing it to climb to the top of a plant, where the ant clamps onto a leaf.
This makes it more likely to be eaten by a grazing herbivore, where the parasite can then complete its life cycle. The ant repeats this behaviour nightly until consumed.
5. Zombie Spiders And Parasitoid Wasps
Hymenoepimecis argyraphaga, a parasitoid wasp, controls its spider hosts in one of the most macabre ways. After stinging and paralyzing the spider, the wasp lays an egg on its abdomen.
When the larva hatches, it injects a chemical into the spider, forcing it to spin a web of perfect proportions, a web the larva uses to cocoon itself. Ultimately, the spider’s body is consumed by the growing larvae. The altered web design differs drastically from the spider’s normal patterns.
6. Caterpillars And The Hairworm
Hairworms have another grisly trick, this time targeting caterpillars. Once the parasitic worms infect the caterpillar, they grow long, thin, and squirm through the host’s body.
The caterpillar then becomes driven by the parasite’s impulses, leaping into nearby water, where it drowns. The worms then emerge from the drowned caterpillar and continue their life cycle. Multiple worms can emerge from a single host, creating a tangled mass in the water that seeks mates.
7. The Parasitic Worm That Controls Fish
The parasitic worm Urocleidoides can infect fish, forcing them to behave in ways that benefit the worm’s life cycle. Infected fish lose their fear of predators, swimming near the surface where they are easily spotted and eaten by birds.
The worms then continue their life cycle inside the bird, completing the final stages of their development. This manipulation increases predation rates significantly. The parasite essentially turns the fish into bait for its next host.
8. The Zombie Crickets Controlled By Parasites
Hairworm larvae infect crickets and other insects in a highly disturbing process. The larvae grow inside the cricket, then take over the insect’s mind, compelling it to seek out water.
The cricket enters water, where the parasite bursts from the insect’s body, completing the life cycle. The cricket’s instincts are completely overridden, leading it to its watery death for the parasite’s benefit. Some crickets can travel significant distances to find water once infected.
