This is the second part of a series of posts about how we might intentionally make spiders adapted for the surface of Mars. The first installment is here How to Make a Better Spider Part 1. If nothing else, you might learn a little bit about Mars. And spiders. And maybe even some other stuff. Who knew writing about spiders could be fun?

In the previous article, we discussed how Martian spiders might adapt to the cold. Because Mars is really cold. Like creatures here have done in cold times, we thought maybe we should make them extra large and furry. I forgot to mention that the lower gravity of Mars (slightly more than 1/3 of Earth's) would probably work in favor of making big creatures. Less to hold them down, you see.

But there's another issue that needs to be considered. Mars doesn't have much atmosphere. And almost none of it is oxygen.

A human, trying to breathe in the tiny, mostly carbon dioxide atmosphere of Mars would suffocate in a very few minutes. If the low partial pressure didn't kill them first, that is. Animals, including spiders, need oxygen to stay alive because it's a wonderful chemical agent. It combines with nearly anything. In fact, Mars is red because the iron-heavy surface has rusted. The process of rusting is also called _oxidation_ because it involves combining with oxygen. Slowly. Combining with oxygen quickly gets you combustion also known as burning.

There's probably a lot of oxygen locked up in the Martian sand. But you can't breathe sand.

How do spiders breath, anyway? They don't have little tiny lungs, do they? Well, it turns out they sort of do. They're called book lungs, because they are tiny tissues stacked on top of each other like the leaves of a book. Don't ask me why they didn't call them "leaf lungs" then. Or page lungs. Or even lungicles. Spiders also have little tubes called trachea that they breathe through, too. I guess neither of those breathing methods is efficient enough by itself to keep them going. That might be a problem. If you want your giant Martian spiders to be able to breathe, you might have to experiment with different conformations of lungs. But the low atmospheric pressure worries me. It doesn't matter how efficient the lungs are if they explode because there isn't enough gas to keep them inflated. No, wait. Then they would implode.

Whatever.

Maybe there's another solution. The main thing that oxygen is used for in the body is to produce energy. Every cell in the body has mitochondria¹ that change oxygen and usually sugar² into energy that can be used to keep things moving. If energy is the problem, maybe we should just implant our mega-spiders with little nuclear power cells. Yes, it's cheating. It means our synthetic spiders won't be able to reproduce, or if they do they won't live very long. Is that a big problem?

We'll get to that later when we discuss why we might want these things to actually exist. At the rate I'm going on this thing, though, it might take yet a third part of this article before I can get to it. Sorry but cool ideas take time to develop!

There might be another way, anyway. Maybe not as impressive as nuclear plants, though. Because of its thin atmosphere, the surface of Mars gets a lot more radiation than the surface of the Earth does. Could we maybe set up our spiders with something like solar panels, to collect radiation to substitute for some of that oxygen they aren't getting? It's not quite as far-fetched as it sounds. Maybe almost but not quite. What if a spider's web was used to soak up radiation instead of trapping prey? Or in addition to? What if they dug holes in the ground to sleep in - or wait for prey to wander by - and covered it with a big sheet of webbing to bring in that radiation? What if the webbing could do photosynthesis like a plant?

Maybe. If I were a physics nerd (which, believe it or not, I'm not), I would try to calculate how much energy per square millimeter one of these spiders would need and compare it to the amount falling on the surface of Mars to show with math what a stupid idea this is. That kind of common sense thinking is absolute murder on creativity, though. Just put it aside for now. The common sense, I mean. You'll need it back later anyway, so why get it dirty here?

Here's another interesting idea. By the way, even if these ideas aren't quite fully fleshed out, I'll bet you could work them into a decent science fiction story. As long as you're not the kind of SF writer who always does the math. But those are few and far between. Even early greats like Arthur C. Clarke and Isaac Asimov, both of whom could do the math, didn't always bother. Sometimes, they just ran with their ideas to see where they went.

Where was I? Oh, yeah. We could also envision that, with energy being in such short supply on Mars, our giant spiders might develop entire ecosystems around it. Whole communities of them might live close together so they could all benefit from the photosynthetic webbing. Or they might learn to act like vampires, siphoning the energy off of each other. Or off the occasional Mars rover they might happen to run across.

Think of it. A whole planet where the entire ecosystem is made up of giant spiders. Edgar Rice Burroughs meets H.P. Lovecraft! And if that isn't enough to give you nightmares - well then nothing much will, I guess.

Next time, in part 3 of this festival of mutated arachnids, we'll talk about reasons for doing this kind of thing other than, "Hold my beer while I genetically engineer!" There are several reasons, actually. And they're kind of interesting.

Here's that prompt: "A captivating scene of a green spider web sparkling in the sunlight, intricately woven with dewdrops that glisten and shimmer. In the background, a futuristic spaceship is landing on a barren red planet with craters and rocky terrain. The contrast between the delicate web in the foreground and the advanced technology of the spaceship in the backdrop creates a surreal and otherworldly atmosphere. The sky is a gradient of deep red and orange, highlighting the alien landscape, while the spider web catches the rays of light, making it appear magical."