Welcome to Science of the Scare! Every month I will dissect a Big Science Question from a horror movie and talk through it in (mostly) easy-to-digest terms.
Science and horror have a wild, entangled history and have left us with loads of questions to ponder. Deep, important questions like: just how many ways could we have a zombie pandemic? Is genetic engineering always a slippery slope to monstrosity? This month’s Big Science Question:
How can vines consume human flesh?
For March Break Month, we’re looking at Carter Smith’s travel horror The Ruins (2008), an adaptation of the novel by the same name by Scott Smith. Americans Amy (Jena Malone), Stacy (Laura Ramsey), Jeff (Jonathan Tucker), and Eric (Shawn Ashmore) are on vacation in Mexico, enjoying some fun in the sun before Jeff goes off to medical school. While partying at the resort, they meet a German tourist named Mathias (Joe Anderson), who tells them about his missing brother, last known to have headed out to a Mayan temple not marked on tourists maps. Seeing an opportunity for adventure with a good-looking stranger, the Americans decided to check out the ruins.
As it turns out, there’s a good reason why the ruins are protected from tourists (besides the fact that mass tourism harms often damages ancient sites like Mayan temples). In this case, the temple is crawling with an aggressive, carnivorous plant. A number of missteps and miscommunications leave the group trapped on top of the temple, surrounded by villagers who are determined to keep the threat of the vine contained.
Carnivorous plants aren’t unusual — we can even keep small ones, like Venus flytraps and some species of sundews and pitcher plants, as house plants. These plants consume insects and small vertebrates like frogs, lizards, and mice by dissolving their tissues in digestive enzymes, which in turn frees up nutrients for the plant to then absorbs through leaf surfaces. Some pitcher plants get a little digestive help from bacteria or mutualistic larvae that eat their prey for them and produce nutrient-rich waste for them to absorb instead. Anecdotally, carnivorous plants have been witnessed digesting bits of human skin (Barry Rice, a cultivator of carnivorous plants experimented with feeding a plant bits of his foot skin shed after a bad case of athlete’s foot, which…is gross), but generally speaking, if you wanted to feed an entire human to a carnivorous plant, you’d have to feed it bite by tiny bite.
This hasn’t stopped past claims of giant, man-eating plants from popping up throughout history. In the late 1800s especially, there was a spate of hoaxes and rumours that various man-eating plants made their homes in Africa and Central America (if this sounds like another colonial vehicle for spreading racist ideas about other nations as “wild” and “savage,” that’s because it was exactly that). The most famous of these hoaxes was probably a story that was featured New York World’s Sunday front page in 1874, about a man-eating tree that bears an uncanny resemblance to the vines in The Ruins.
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The newspaper story featured a letter from [definitely fictional] botanist Karl Leche to his fellow [equally fictitious] botanist friend Dr. Omelius Friedlowsky. In it, he describes a strange tree with writhing tendrils that is worshipped by the [also non-existent] Mkodo tribe. Sensing a pattern? The account went on to describe, in gory detail, in which a woman from the tribe was made to climb the tree, drink its nectar and then be strangled to death by the plant’s tendrils. The story was published world-wide and, even though an exposé in 1886 denounced the whole thing as a hoax, explorers were still traveling to Madagascar in the 1930s.
Other man-eating plant hoaxes include the “vampire vine” of Nicaragua, which was described in 1891 in terms even more similar to the vines that we see in the movie: “In cutting the vine, the twigs curled like living, sinuous fingers about Mr. Dunstan’s hand, and it required no slight force to free the member from its clinging grasp, which left the flesh red and blistered.” This plant was also eventually revealed to be a fabrication, a fancy spun by the paper’s editor.
But let’s consider the hungry vines in The Ruins as if they were real. How could they manage to eat people? The vines don’t appear have any of the usual structures for producing or holding digestive fluids. They don’t have any pitcher plant-like structures and they don’t appear to be coated with any sort of digestive goo or juices to help break down tissues. The descriptions of the plants behaviours are even gnarlier in the book, where the vines are said to be visibly sipping at blood and puddles of vomit.
Based on the desiccated remains that are found in and on the ruins, the vines in The Ruins seem to subsist more on blood and bodily fluids than on flesh. The vines grow quickly and burrow into wounds, exploiting those entry points to gain access to wet blood inside. They likely absorb blood through newly placed root systems in the body. Many vines, from invasive kudzu to favourite houseplant pothos, spread by placing down new roots that can sprout from nodes on the stem. So, as long as the fast-growing vines find a space to grow roots from a node, they can continue to thrive and produce new vines, even if they are hacked apart. Between robust root systems and the spores that were seen collecting on the tourists’ sweaty clothing as they brushed up against the vines, no wonder the villagers were so concerned about keeping the killer plant contained.
What’s even cooler about these plants is that they’ve evolved adaptations to make it more likely that their prey will become wounded. In short, these plants is that they are absolutely predators, and the way that they hunt their prey is by using an adaptation called aggressive mimicry.
Mimicry is a common enough adaptation — a species develops traits that are modelled off of an unrelated species’ traits to gain some sort of advantage. We see this in species like the harmless Mexican milk snake, whose stripes imitate the venomous coral snake so that predators will think that it is dangerous and will leave it be. Or in the shapes of orchids that have specialized their flowers to look like female bees to try and attract male bees to mate with the flowers and pollinate them. Aggressive mimicry is a very specific form of mimicry that predators or parasites display traits that are considered to be harmless, and so trick potential prey into not identifying the threat for what it is.
More than once, the plants first lure the travellers to lower themselves inside the temple by imitating the sound of a ringing cell phone. The first time venturing into the temple manages to injure two people enough for the plants to gain entry into their bodies. Later we hear them mimicking the voices of different members of the group. Although we can speculate that these sounds might actually be auditory hallucinations brought on by extreme stress and heat exposure, in the universe of the film, the sounds do seem like they are being produced by the blooms on the vine. In real life, we’re still relatively early on our journey building our knowledge base on plant communication, but what is apparent right now is that most plant communication seems to use chemical signalling, and any sounds that plants might produce aren’t in the range of human hearing (and definitely aren’t as complex as human speech).
“What’s even cooler about these plants is that they’ve evolved adaptations to make it more likely that their prey will become wounded. In short, these plants is that they are absolutely predators […]”
Beyond luring the tourists through dangerous terrain, the plants’ aggressive mimicry gave voice to real anxieties and tensions within the group, from fears of infidelity, to whispers that Stacy, certain that her body was infested by the plant should cut herself open — a desperate act that only made her body even more vulnerable to attack.
On that note, I’m going to spend the rest of my day watching Venus flytrap plant care videos and not thinking about the concept of parasitic vines growing under my skin.
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