Giant Spiders (the Spider Goat is real)

by Dan Stout

The other day I came across mention of Congolese stories of the J'ba Fofi. These creatures are supposedly giant spiders (about 5 feet across) that live in the jungles of the Congo, preying on animals and the occasional unwary human. I've always been told that such a large arachnid would be impossible, and out of curiosity I thought I'd try to understand the reasons why. In the process I came across something every bit as amazing as the J'ba Fofi: spider/goat hybrids which are living on a ranch in Wyoming.

As a fan of weird tales and unknown animals, I've seen the concept of giant spiders surface in popular culture countless times. Some of the more memorable include almost all of Tolkein's works, and of course all of the oversized 1950's sci-fi creatures. Ray Bradbury's short story “The Finnegan” is a personal favorite, as is “The Spider”, a radio drama which appeared on the show Lights Out in 1943. And last but not least there is an episode of The Twilight Zone that I personally credit for my fear of spiders to this day, an episode which was also written by Ray Bradbury (damn you, Ray!).

Reports of spiders the size of J'ba Fofi also can be found outside of Africa, from the Urban Legends of the American Bayou, and the stories that have filtered through the armed forces since the first Gulf War about Camel Spiders, with occasional emails getting passed along featuring photos of monstrous looking critters. In addition, tales of the Chupacabra, while not being described as a giant spider, often behaves as such, leaving its livestock victims drained of fluid, with two puncture wounds in their sides.

Giant Spider Reality Check: They don't get that big.

The Camel Spider photos are well-known exaggerations. In reality they top out a little over 6 inches in size, which admittedly is bigger than anything you want hiding in your boots. Their bite is extremely painful, but they don't attack humans or livestock, and thy don't jump onto your face. They're also technically not spiders, but I'm not pedantic enough to argue that point. See this article on for more info. 

There's a few reasons to doubt that spiders could grow to giant size in today's environment. Primarily because spiders do not have lungs in the sense that you or I do. Instead, they have either “Book Lungs” which are a series of flat sheets which collect oxygen, or tracheae which are essentially tubes that run into its body, or a combination of both. Generally speaking, the faster and more nimble a spider is, the more likely it is to have tracheae-dominant oxygen supply. The key point is that spiders, just like insects, don't have lungs to act as bellows pumping oxygen through their systems. Around 350 million years ago the Earth seems to have had a denser, more oxygen-rich atmosphere, which allowed insects' tracheal tubes to carry more O2 through their bodies without having to increase the volume of air processed. This allowed insects to grow to larger sizes and achieve flight easier, and there is evidence of insects which fall within the size range attributed to creatures like J'ba Fofi. While there is no fossil record of large spiders from that time (the one which was a possibility was later shown to be a sort of early crab), the difficulty of finding an exoskeleton fossil doesn't rule out the possibility that they existed. (And with some of the incredible fossil insects found so far, you never know what will turn up.)

An illustration from showing "Book Lungs"

An illustration from showing "Book Lungs"

What this means is that if a spider were of enormous size, then its physiology would have to be considerably different than spiders as we know them now. Their breathing system would have to function differently, and there may well need to be some element of skeletal support to replace/supplement their exoskelton. In order to see such changes there would have to be some major changes in the spider's DNA. But what are the chances that someone would go messing around with the spider gene pool? Well.....

Spider Goat Reality Check: Truth is stranger than fiction

In 2000, a Canadian company began breeding goats that had been modified with orb weaver spider DNA. If you're like me, this sounds unbelievable. Here's some coverage from the BBCThe New York Times,  and an informative video produced by VCU.

The rationale behind the project was based around the incredible range of potential uses for spider silk . From Lawrence Osbourne's NY Times piece:

Nexia foresees tapping into the $500 million market for fishing materials as well as the $1.6 billion market for industrial fibers in the near future. And the haute-couture world is already intrigued by a nearly weightless gossamer-like fabric. But the real gold mine might be body armor: the Pentagon is working with Nexia to develop a prototype of a new kind of vest that might be made entirely out of goat silk. The vest would be only a little thicker than nylon, but it could stop a bullet dead.


In any case, the properties of spider silk have long been recognized. Fishermen in India have always prized it for the making of their nets; American Civil War soldiers frequently used it as a surgical dressing. The problem lay always in getting sufficient quantities of it. Whereas silkworms are peaceful herbivores and can easily be farmed, spiders are aggressive territorial carnivores that need plenty of space and solitude. In farm conditions, they moodily attack and eat each other.

The solution to this problem was to find a way to create an animal that had the ease of husbandry and the silk production of spiders. Enter Prof. Randy Lewis of the University of Wyoming. He lead the team that spliced spider genes into goat embryos that were then cloned to make two kids. These goats were then bred, passing the added spider genetics down their bloodline. Nexia worked with a number of breeds, with the total number topping out around 500. There is a good summary interview with Randy Lewis here .

However, Nexia ran out of cash, and by 2005 hundreds of spider goats had been euthanized. The few dozen that remained were transported to another Canadian farm, where they were eventually picked up by Lewis, and brought back to Wyoming. They are there still, and the research continues. In January of 2011, David Pogue's “Making Stuff Stronger” program for the PBS series Nova spent some time at the facility and gives a very good explanation of the process (at the end of this episode, if you're curious).

Prof. Lewis and his team are doing good science and have really intriguing ideas. Although it's certainly startling to hear about a spider goat, it's important to keep in mind that it's only 1/70,000th spider. If you want to describe the process in a more palatable way, consider that spider silk is 100% protein, and goats' milk is filled with different proteins. These goats have just been tweaked to allow this one additional protein into their milk.

So if you've read this little article and if you still find the J'ba Fofi ridiculous, if you laugh at the unbelievable things that some people claim to have seen, then imagine siting down with a member of the Baka tribe, and explaining that in the middle of the United States, there are goats which are part spider casually living out their lives, running around on a farm munching on plants. And maybe, just maybe, those plants might also be part spider. Don't believe me on that one? Check out the University of Wyoming's patent application.

Pleasant dreams, kids.

spider goat photo from:

by Dan Stout