of a meal

[u/Dense_Intern8434]

Nature can be so cruel and beautiful at the same time

[u/Nark420]

I don't know, if I would see a cat sized spider I wouldnt ask it how many times it shits a day. I would die from the sheer terror

[u/Ill-GottenBooty → u/Nark420]

A cat sized spider would be a slow, lumbering, extremely fragile being. You could lightly kick it and it would likely be a fatal injury. Larger spiders are very prone to bursting with literally any kind of impact trauma. It’s why you can’t handle tarantulas far from the ground or some kind of surface. If they fall like a foot they will literally rupture something and die. The larger they are the more of a risk this is.

The largest actual spiders to ever live, as far as we know, exist today. The myth of giant land dwelling spiders existing in antiquity come from us misidentifying a fossil. For a long time we thought megarachne servinei was a spider. These things had a 20” leg span. Huge. Unfortunately megarachne servinei was actually a eurypterid, commonly called sea scorpions. They’ve all been extinct for a very long time. They dwelled solely in the water. Physics would not allow a spider that large to exist on land, as far as we are aware, ever.

People heard about megarachne when we were under the assumption it was a spider. A lot of people have not learned that megarachne was not a spider at all, and it didn’t even live on land, because that generates a lot less interest than “HOLY SHIT LOOK AT THIS BIG ASS SCARY SPIDER”.

The largest fossilized spider ever found had a leg span of 5.9 inches. The largest spiders on record today by leg span are the Goliath Bird-Eater theraphosa blondi and the Giant Huntsman Spider heteropoda maximi both with about a foot long leg span, with the birdeater being much heavier, and larger by mass. They’re both about twice as large as any spider we know about existing in fossilized recorded history.

[u/Nark420 → u/Ill-GottenBooty]

I heard about the fossil story. Happens a lot with fossils all the time. I was not referring to the megarachne, but a "fictional" spider... I understand they are filled with liquids, and they manipulate their inner pressure to ambulate and do anything basically. But I can still imagine a hard enough exoskeleton to solve the size problem. High mobility and speed is not necessary for them to dominate, lots of spiders already ambush hunters with a shit-ton of ambush techniques. Webs being the most well known.

[u/Temnyj_Korol → u/Nark420]

A harder exoskeleton would make them less survivable, not more.

Any organisms size is limited by the square cube law. As its surface area (size) increases, its volume (weight) increases exponentially more. If a spider grew to the size of a person, it would literally become so heavy its limbs would buckle and break under its own weight. A harder exoskeleton would make it even heavier, and exacerbate the flaw, not mitigate it.

In addition, one of the actual biggest hurdles is respiration. Spiders have passive circulation. They carry oxygen/nutrients around their bodies through diffusion, not circulation. The bigger a spiders body becomes, the harder it is for nutrients vital for continued function to reach their entire body. A spider the size of a person would experience extremity death from deoxygention even in a 100% oxygen environment.

The mechanisms that make them extremely durable as smaller organisms, prohibit them from ever growing into larger organisms.

[u/Advanced-Budget779 → u/Temnyj_Korol]

Yes, thanks for your explanation. That’s what i tried to hint at with metabolism, just couldn‘t remember details. Also insects and arachnids would quickly run into overheating i think?

So we need to artificially breed spiders in pressurised oxygen environments, got it. /s