In Mass Effect, players explore many alien worlds across the Milky Way galaxy, and on many, they'll encounter some of the franchise's most interesting and unique aliens. Some of these alien critters, like the monkey-like pyjaks or the harmless gasbags of the idyllic Eden Prime, are cute and funny, but there are also titanic nightmares waiting to gobble everything up like the thresher maws.

Thresher Maws are massive, armored worm-like creatures that appear on remote worlds, tunneling beneath the planet's surface and occasionally popping up to feast on any fauna they find. From a design standpoint as monsters, thresher maws are an engaging and challenging mini-boss battle but, speaking in terms of hard science, their physiology is simply impossible, even for Mass Effect.

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Thresher Maws Are Too Big For Their Own Good

mass effect thresher maw vs mako

The Mass Effect games needed mini-boss battles aside from the likes of the cyborg Saren Arterius and Matriarch Benezia, and to that end, the design of thresher maws is ideal. These huge, terrifying beasts can appear out of nowhere on remote worlds, challenging Commander Shepard to take them down aboard the Mako while avoiding their acid attacks. And, of course, there is that thresher maw battle during Grunt's loyalty mission, and killing it means the Urdnot warriors can savor thresher maw steaks while Grunt earns bonus glory for taking down such a foe. Finally, there's the matter of Kalros, the mother of all thresher maws, which can be summoned to take down the Reaper destroyer that took up position near the Shroud.

But in a franchise like Mass Effect, which prides itself on realism so much it uses details like Newtons and force to explain Biotics, Thresher Maws are an odd science-fiction conceit. By no means could a creature like a thresher maw exist in the real universe, even on far-off alien worlds like those depicted in Mass Effect. The main problem is their size, which is wildly impractical. Some animals are certainly much larger, but being bigger comes at a serious cost. Larger animals need a lot of calories to stay alive, and while thresher maws dodge that issue by eating ores in the ground, that doesn't explain them all away. As animals get bigger, they tend to get slower. Those that are truly massive tend to be herbivores since they can't outrun anything (such as the giant Thorian, which doesn't even move).

Thresher maws are described as being unusually fast for their size in Mass Effect lore, but that's so that they can catch up to Shepard and provide a fight. Something that huge, and that heavy, probably wouldn't be able to move much at all, let alone fast enough to chase the Mako around. Worst of all, a typical thresher maw (especially Kalros) would destroy itself with its sheer bulk, thanks to the square-cube law.

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Thresher Maws Lose The Fight Against Gravity

thresher maw mass effect

Ultimately, thresher maws are a work of science fiction, and the fun shouldn't be ruined by real-life laws of physics and nature, but it is still worth considering. Not only are massive creatures very hungry for calories, but they are proportionally heavier than smaller animals. As animals scale up, the design of their bodies changes to accommodate their weight, such as their skeletons. If a mouse and an elephant were somehow the same size, then the elephant would have thicker and sturdier bones by design, and the mouse can get away with having more slender bones. This is because a mouse is small enough that its gravity is mild, while the elephant, relative to its size, would feel the pull of gravity more strongly. The result would be an elephant collapsing if its skeleton was proportionally the same as the mouse's own.

This is where the square-cube law comes in, stating that if an object's linear size increases, such as length or height alone, then the surface area increases by the square of that length boost, and the volume increases by the cube. So, a huge animal such as an elephant or whale has far more volume relative to its surface area and length than a mouse or rabbit would, and scaling up a mouse to elephant size would crush it (and it would overheat, too). The largest real-life animals are all found in the ocean, both extant and prehistoric species, since the buoyancy of water protects them from gravity. Land animals such as thresher maws fall victim to the square-cube law and would be far too heavy and warm to survive, even underground. No real animal of that size could tunnel through the earth at high speed, pop up into the open air, then retreat and keep moving. This is especially true for Kalros, no matter how much ore it eats to satisfy its caloric intake.

On a final note, larger ground entities such as the Reapers can survive despite their bulk due to having gravity-nullifying mass effect fields since the square-cube law applies to all physical entities, not just animals. Thresher maws, however, lack that benefit. As for giants in other franchises, such as Dune's sandworms, it's up to those other franchises to explain how the aliens overcame the square-cube law. Physics cannot be denied.

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