The Complexity of a Spider

Geoffrey Baron
3 min readMay 26, 2021

My daughter and I were admiring a small band/cluster/pile/ball/google? of baby spiders the other day.

We watched as many sat perfectly still and others were busy adding new little strands of web to their little nest like structure.

One long strand went up to a branch a foot or two away and ran down to the deck.

We both wondered why.

Who was the brave spider that led that building project and why? What was the thought process behind this? How did the micro-spider view its surroundings and make that bold decision?

I’ve done enough programming to know just how hard it is. Seemingly simple things can quickly spiral into complex pieces of software. If this happens, then do this…but what if this other thing happens? There is a lot that can wrong wrong when you are dealing with users. Spiders have to deal with CATS.

Robots have sensors to take in information around them that allow them to navigate. Many spiders have eight eyes and myriad of other sensors including hairs and slits that allow them to taste, smell, and sense vibrations.

Each one of these sensors would need some programming. A bit of code that allows them to take in information to be processed for decision making. And since spiders don’t exactly get a lot of lessons from their parents they need to have pretty much all their programming from day one.

This is why a spider’s body is roughly 80% brain. That’s right, there is so much code there it fills pretty much everything in a spider. Think about that next time you smash one.. that goo is almost pure intelligence.

The complexity of all that visual information coming in from the those eyes.. and then it needs to combined with the information from all the other sensors.. that then needs to run through its database of known threats and or list of acceptable foods. Fight? Or Flight? Eat’m or no eat’m?

Then the hard part. Move this part of this leg, then this part.. then this part of this leg. Nope, that’s not solid, move that leg bag and the other one forward.

If someone coded all of this and you looked at it it would look like the Matrix. Now imagine it in DNA form and then neurons.

Completely mind boggling.

We are talking about thousands upon thousands of lines of code.. just for moving all eight legs in a meaningful way. And there is new information coming in all the time so constant adjustments need to be made.

I read about an experiment once where “scientists” attached tiny explosives to a cockroach and then filmed it running. The tiny explosions barely blew the cockroach off coarse.. it was able to make adjustments to its movements so fast the scientists were questioning their own reality.

Jumping spiders seem to move at similar speeds.. those too fast for the human eye (10–12x faster than human reflexes). So, not only do spiders carry around a ton of software, a huge database of cataloged threats, web building plans, etc… but they can also run through all these calculations and make decisions has speeds that rival, well, everything.

It’s to dismiss this complexity with simplicity. They are faster because they are smaller.. shorter neurons.. small limbs to move.. their stimuli not exactly 4K 3D models with trillions of pixels. These are true statements. However, when you flesh out the whole picture you begin to see a spider is insanely complex.

We didn’t even touch on replication. They need to mate and reproduce. Layers and layers of sub-systems here. It hurts my small mammalian brain.

The punchline here is: Humans have done some amazing things but we would have reason to be real proud if we come up with anything nearly as complex as a spider. Maybe someday, but it would essentially be.. a spider.

PS: I hate spiders, but I do appreciate them.

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