Now to the point: I am extremely skeptical of the giants that are being reported here, and the reason is that the size of very large (or small) creatures of any sort involves something called the “square-cube law” I’m surprised that nobody addressed it in all these posts. Basically, it says that if you scale something up without changing the proportions, (and that phrase is important to remember) the mass goes up by the cube of the linear scale factor, but the cross sectional area of any component goes up by the square of the factor. So, if you double the body length, all proportions remaining the same, the mass is 8 times greater, but the cross-section of the legs is four times greater. The stresses on the exoskeleton and the muscles is twice as great. Now, since the legs are correspondingly longer, too, the bending moments are proportionately greater. It works across the board, and explains why elephants have legs that are proportionately much bigger than springboks, and why springboks spring but elephants (reportedly) cannot jump at all, as well as why skinny little 14-year-old figure skaters with legs the size of your wrists can do those awesome triple-lutzes that Arnie Schwarzenegger could never do. So a spider, to scale up to dinner-plate size, will inevitably have disproportionately large-diameter legs, compared to a small one. (this is based on the assumption that nature designs things efficiently: the exoskeletons and muscles of your typical house spider are about as efficient, powerful, and light as nature knows how to make them. So if you scale them up, for example, the exoskeleton is not going to miraculously become ten times stronger in compressive strength than the house spider. I’m talking strength in pounds per square inch or whatever unit system you choose. Remember, I’m an engineer, used to working out designs that don’t break, without invoking miracles.) So how do king crabs function? they live in sea water, so the weight those incredible long legs have to carry is decreased by the partial buoyancy of their bodies. Crabs that live on land do not have 2-foot-long legs. They are short and compact. So I am extremely skeptical about super-size spiders.

How about a giant orb-weaver making a giant web? Read up on how they build them, and consider how that web might be made and what the scaffolding might have to consist of. I’m still skeptical.

But how about the foot-long centipedes and millipedes? Many, many legs, relatively short. Scale up your everyday household centipede and the legs need not be visually disproportionate, especially if the number of segments increases. I don’t have a problem dealing with centipedes and millipedes a foot long, even two feet.

Are they poisonous the humans? I read one post that sounded like the bite of a Brown Recluse. Many spiders give unpleasant bites, black widows bites can be deadly, but the brown recluse is really, really nasty. I knew a fellow that was bitten by one, and I find the story of the fellow whose skin split from the swelling to be quite believable. They are found in the US. The reaction sounds, actually, like some sort of horrifying immune reaction, rather than the result of some injection of a proportionate volume of digestive enzyme or whatever. They just aren’t that big. But I suggest that if you don’t like spiders, you look up “Brown Recluse” and learn what they look like. Just in case…

We had the same centipede things in Colombia. I have seen them myself on several occasions. They indeed do grow that large, and the bite burns like acid. I have been bitten by smaller versions, not sure if they were juveniles or different species. I didn’t think that they would have them in Asia, but why not?

Traveler, if you could give me as much info on these centipedes as you could from Columbia, like description, location, and everything else, I would be most grateful!

The creatures in the first photograph appear to me to be exceedingly large examples of the Sun Scorpion. Note: The Sun Scorpions here have head and thorax that are only an inch or so long. These look MUCH bigger. Glad they are over there!

Crabs are arthropods. So are spiders. Land crabs can be a foot across. Some marine crabs are much bigger, and they can survive on land for a time so long as they are close to water. It’s conceivable that large crabs could be mistaken for spiders, especially if the crab was in an location where crabs are not usually found. People being terrestrial creatures, most people, confronted suddenly with a round-bodied, many-legged arthropod, would think “spider”. Perhaps the “giant spider” in Louisiana was a large crab covered with spanish moss? Or even a fungal infection on its shell that looked like black hairy growth?

On the other hand, couldn’t some species of spiders have evolved a thicker, tougher exoskeleton, similar to that of land crabs? Larger animals are generally more rare than smaller ones, and giant spiders would probably require quite a bit of territory in which to live and hunt. I think that as the remote forested areas of the Earth become more exposed and studied, many more species will be discovered. It would not surprise me if some of those species are huge spiders.

Picture 1

Picture 2

And unfortunately, the giant Iraqi spiders myth is growing legs
Cindy Sheenan referred to them in a recent post, in reference to the various hardships the soldiers had to deal with over there, she mentioned ’spiders the size of puppies’.