Zombies are real

Forget vampires; they’re just a result of a poor understanding of death and decay – and fertile minds. Forget werewolves, too – we’ve got a suite of explanations for stories of these hairy hairbrush-needing beasts, ranging from genetic disorders, psychiatric syndromes and rabies, to serial killers (OK, I guess werewolves sound quite interesting after all). No, good reader, we’re so done with these mundane monsters, and we’re ready to take on some real-life horrors. Zombies. Zombies are real.

Yep, you heard us. It’s time you learned to fear the dark once more (that sounded a little ominous – sorry), and turn your attention to the real-life science we’ve collated, showing how organisms can transform – through natural or artificial means – into mindless, sometimes violent, monsters.

The ‘zombie’ ants controlled by fungi

Admit it, fungi are already a bit spooky. Creepy, reaching tentacles of a strange flesh shared with microorganisms and even the roots trees, exist all around us. There is one species that is particularly frightening, though. The Ophiocordyceps unilateralis fungus, found in tropical forests, has evolved a rather unique way of casting out its spores into the environment to reproduce – it takes over the bodies of foraging ants and sprouts a bulbous spore-holding capsule from their helpless heads.

‘Erm, what?’ is presumably the reaction of the biologists who first studied this fungus. When these ants come into contact with specialised spores, they attach and penetrate the exoskeleton, taking over the unlucky ant’s body and behaviour. The zombified ant is then forced to climb atop a nice, high vantage point (e.g. a leaf), where the hideous transformation truly begins. The fungal structures grow, draining the ant’s body of nutrients, until it sprouts its stalk through the ant’s head and forms the spore-containing capsule. Then, you guessed it, the cycle can begin again and more zombies are made. Spooky.

The mind-controlled mice who willingly accept death

This isn’t about that research that genetically engineered mice to respond to brain laser stimulation to increase predatory behaviour, although a ‘switch’ for violence does sound a little like the first piece of research in a slippery slope towards the events of Resident Evil. No, it’s not even about ‘Zombie mice,’ as they’re called by wildlife advocates, which are invasive mice that cause damage and death to the resident ecosystem, even having been known to eat the heads of live albatrosses.

No, this is about something far more widespread.

This is about a single-celled parasite that infects up to one-third of people around the world. That’s right, you may as well say ‘hello’ to Toxoplasma gondii now, because you’ve got around a 33% chance of it being inside you right now. Don’t worry too much, though, unless you really like mice.

Why mice? Because this parasite can influence the brains, maybe permanently, of mice – leading them to their deaths. Showcasing a fascinating, and disturbing, trick for reproduction, the parasite has evolved to inhibit the fear of (and promote attraction to) cat odour in rodents. It does this because it can only sexually reproduce in the cat gut – so it has seemingly evolved a convenient shortcut to this precise environment: by leading infected mice straight to it (that’s right, by being eaten). Researchers reckon this might represent a permanent structural change in the brains of infected rodents.

We would tell you about what the parasite might do to human behaviour, but that might scare you too much – even for Halloween.

Image by David P. Hughes, Penn State University.


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