One of the most striking images from George A. Romero’s zombie classic Land of the Dead is when an army of the dead slowly rise from the murky waters of a river to attack the previously secure city of Fiddler’s Green. But the concept of amphibious zombies had already existed for years, including great cult films like Zombie Lake and Shock Waves starring Peter Cushing.
Apparently the idea is that zombies are undead and therefore don’t require oxygen to exist. Obviously it makes for a great movie, but could the living dead actually survive underwater?
Our previous research offered a number of explanations, mostly focused on the respiratory system of aquatic mammals like dolphins, seals, or beavers. But a recent study published in the scientific journal Cell offers the first clue that a DNA mutation in some humans could actually provide a decidedly dangerous genetic advantage for surviving underwater.
Sarah Gibbens at National Geographic describes how a Thailand tribe may be the first known humans genetically adapted to deep sea diving, diving-related phenotypes, and hypoxia.
If you hold your breath and plunge your face into a tub of water, your body automatically triggers what’s called the diving response. Your heart rate slows, your blood vessels constrict, and your spleen contracts, all reactions that help you save energy when you’re low on oxygen.
Most people can hold their breath underwater for a few seconds, some for a few minutes. But a group of people called the Bajau takes free diving to the extreme, staying underwater for as long as 13 minutes at depths of around 200 feet.
Researchers at the Center for Geogenetics at the University of Copenhagen studied the physiological and genetic adaptations found in these “Sea Nomads” and stumbled across a gene called PDE10A, which is thought to control a thyroid hormone linked to spleen size.
It was eventually discovered that the median size of their spleen was almost 50 percent larger than the average human, which perfectly aligns with the disproportionately large spleens that are often found in many of the aquatic and marine mammals that we mentioned previously.
While a dramatic increase in water pressure can often cause blood vessels to fill and rupture, resulting in a gruesome death; genetically inherited adaptations or DNA mutations could help prevent that effect according to Richard Moon from the Duke University School of Medicine.
Could the zombie virus somehow manipulate our genes and hormones, eventually resulting in an enlarged spleen adequately suited for underwater survival? Perhaps the living dead aren’t actually breathing afterall, but have simply become well-adapted at holding their breath!
To learn more, we suggest you read the original research paper “Physiological and Genetic Adaptations to Diving in Sea Nomads” as published online by Cell, or just check out this amazing article over at National Geographic… because what you don’t know can eat you!