The recent Netflix film 'Spaceman' is an adaptation of the book Spaceman of Bohemia, written by the Czech/American author Jaroslav Kalfař. It is about a lone Czech astronaut travelling a long distance in the solar system to investigate a strange space cloud. A major theme of Spaceman is the loneliness of the astronaut. If you like philosophical themes and are not in a hurry, Spaceman is well worth watching; however, those who prefer ray guns and explosions might like it less.
But this blog is about speculative biology of the extraterrestrial kind, not about film reviews. While the astronaut, Jakub Procházka, is lonely and far away from other people, he is not alone. I am not talking about the ship's cat here, not that seems to be one. An alien being that is best described as a spider the size of a small child shows up aboard. How is unclear and you will probably wonder whether the spider is real or whether we see a hallucination springing from Jakub's too lonely mind. The internet seems full of discussions of that particular topic, so I will not discuss this. Well, in fact, you do see a small spider moving under Jakub's skin in the beginning of the film, which seemed to me a strong hint that the spider originated inside Jakub, not as a physical being, but as a concept.
Anyway, the nice thing is that we get to see the space spider in sufficient detail to analyse it as a speculative biology entity.
Why is it called a spider? You wouldn't expect alien beings to conform to Earth cladistics, after all. But there are certainly similarities. It has eight legs with long slender elements sticking out sideways. There is a big bulging abdomen, as well as a head. If it would be a proper Earth spider, that head should be fused with the trunk to form a cephalothorax, but this space spider head seems movable relative to the trunk part. The head has six eyes, not eight, even if some reviews mention eight.
Click to enlarge. Nentwig et al. All you need to know about spiders. Springer 2022
Click to enlarge. Nentwig et al. All you need to know about spiders. Springer 2022
The eyes of Earth spiders are quite interesting and variable between families of spiders. There are not always eight, in fact, and six is definitely possible with Earth spiders. The two images above show that clearly. The eyes of our space spider, christened Zanuš by Jakub, appear to have pupils. The eyes seem immobile, and they are enclosed by a ring of elastic tissue, allowing them to become larger and smaller in apparent diameter. That is a clever trick that helps convey emotions. There are two large eyes and four smaller ones, but otherwise they all look the same. On Earth, different eyes have different functions, and that shows up in their size, colour as well as the apparent direction they seem to be aimed in. We will get back to that later.
There are two very large cheliceres pointing straight down from underneath the head. I haven't seen Zanuš using these fangs and do not know what they are for. Then again, what can fangs be for? It does make you wonder what these space spiders do in their natural environment.
There are additional limbs around the mouth, and in one touching scene, shown above, Zanuš accepts a spoon from the astronaut with some food on it. These mouth limbs can then be seen to be tentacles, and tentacles are definitely not in the anatomical repertoire of Earth spiders.
There is one more big departure from the Bauplan of Earth spiders: Zanuš is obviously endoskeletal, as can be seen from the clip. There are tendons connected to bones, and the entirety of the body is covered by hairy skin. This is certainly not an exoskeletal joint with hinges open to the outside world. The joints are, like vertebrate joints, well and truly inside the leg. The legs, by the way, end in two prehensile fingers each. Zanuš clambers around the inside of the spaceship grasping objects with these tiny hands.
So what does all this suggest? A first explanation is that, if Zanuš is a figment of Jakub's imagination, Jakub knows very little about spiders. I doubt that real astronauts get much zoological training, so that is fine. A second option holds that Zanuš is a real being; inside the story, of course. If so, his Bauplan is interesting, and we will get to that. The third level is the one the creature designer and film makers used: why did they choose this design?
Let's play along and see what we can make out. We have an endoskeletal animal the mass of a small child, with lots of fairly thin legs sticking out sideways. The legs, fur and locomotion all suggest a terrestrial origin; this is not a swimming animal. The legs are very spindly and stick out sideways; that, plus the presence of tentacles, suggests a world with very low gravity. The ability to grasp objects all around further suggests that the creature would be at home in a 3D environment, such as tree branches.
Click to enlarge. Nentwig et al. All you need to know about spiders. Springer 2022
One thing bothers
me in all this: Zanuš' eyes all look in the same direction. In a 3D environment,
it pays to be able to look in most directions at all times. If your Bauplan has
multiple eyes, it makes sense to move some to achieve all-around vision. Spider
eyes follow that principle, at least for some families, as shown above. In
contrast, if your Bauplan only provides two eyes, which is a poor choice if you
ask me, then evolution can be expected to place them where they do best. Here,
they would be seeing what you eat and also covering as much of the world as
possible. Not surprisingly, the eyes of
many fishes and birds that do live in a 3D environment are placed at just the
right spot to achieve such goals. Of course, many birds and mammals have eyes
that depart from that pattern. If you
only have two eyes, stereoscopic vision can apparently outweigh the need for
wraparound vision. With multiple eyes, you can easily get it all, but Zanuš' eyes
all look ahead. That seems odd.
In the story, Zanuš proves to be a thoughtful and respectful psychotherapist. You need good eyes to pick up tiny nuances in expression, posture and movements that tell you a great deal about someone's state of mind, but not eight ones!
A final word in this rather meandering post. I cannot speak for the general audience, but I quickly liked Zanuš, perhaps because I am not really afraid of bugs and small arthropods. I rather like it that the film makers dared choose a shape that many people find repulsive. I do not know whether many people actually turned the film off, disgusted by Zanuš' spider shape. I hope not, because the world could do with a bunch of sympathetic Czech/alien psychotherapist space spiders. Then again, I still wonder what Zanuš' people use those enormous fangs for on their home world...
