Is there any evolutionary reason behind Kryptonians having x-ray vision and the ability to shoot lasers from their eyes? In an answer to the question How does superman fly? , it is stated that

Lex Luthor once theorized that Superman had to stem from a gigantic planet with enormous gravity, where his species had developed natural anti-gravity organs to be able to function; on Earth, this would allow him to control his own gravimetric field in order to fly.

Are there any such evolutionary reason behind Kryptonians having the ability asked in the question?

  • 1
    I feel like if you offered laser eyes to a cheetah, it would be like "yes please."
    – Misha R
    Apr 21, 2016 at 6:52
  • 9
    Shockingly, the Kryptonians who could see other Kryptonians hiding behind walls and shoot them with their laser eye-beams survived longer than those who could not. Jan 16, 2019 at 14:25
  • lol. Ok Darwin. That is funny though.
    – MrInfinity
    Dec 22, 2022 at 16:33

7 Answers 7


Remember that these abilities are not unique to the humanoid Kryptonians but all Kryptonians. An obvious example would be Krypto the Wonder Dog. I don't know that we have ever seen the power of Kryptonian plant life, but all of the higher life forms we have seen on the planet become extra-powerful under a yellow sun.

This argues for the power being developed by a common ancestor in the distant past, perhaps even back when Krypton had a yellow sun. It was developed as both a detection mechanism (the ability to see predator and prey through anything) and a self defense mechanism. As Krypton's sun went red, those abilities diminished, but by that point life had already scattered and adapted to new niches.

In addition, all Kryptonians would have been descended from that common ancestor and would have inherited both the ability to use the power but also the toughness to resist it - notice how useless laser vision is on Kryptonians?

But when Kal-El comes to Earth, these dormant abilities wake up again. So the most scientific answer I can give is that they had a common ancestor.

  • Could argue that the indestructible flower from new krypton in All Star Superman is only indestructible because it's under a yellow sun
    – Recycle
    Apr 15, 2016 at 8:52
  • Haven't read All Star in a while but I don't remember an indestructible flower. If it's there, then it argues for the abilities developed from far, far earlier in their evolution.
    – Broklynite
    Apr 15, 2016 at 9:55
  • its at the end of this article dc.wikia.com/wiki/Kal-El_(All-Star_Superman), where Future Superman places it at Jonathan Kents Grave. ;)
    – Recycle
    Apr 15, 2016 at 10:05
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    I dunno how much we can talk about evolution in old krypton using life from the far future on new krypton, so I'm going to leave my answer as it is for now, but thank you for the heads up.
    – Broklynite
    Apr 15, 2016 at 10:10
  • Its also disputed canon, so its probably best to leave your answer as is.
    – Recycle
    Apr 15, 2016 at 10:15

If you have the pure scientific view of evolution, then evolution is not guided. Individuals get random mutations. And if a mutation helps this individual to create more offspring, then this "mutation" spreads out and ousts the others without this mutation.

So IF a random mutation creates an individual with x-ray or lasers, it is quite plausible that it would have great advantages and create more offspring.

So the "reason" that this feats are kept in there genetic pool is because it helps surviving better.

For the origin there is no reason. It's random mutation.

So a better question would be, how does a mutation create such things and how is this biologically possible. But I don't think you get scientific answers for this.

  • Given the sheer number of gods, Gods, and God-like entities, as well as magic and everything else, it begs the question as to just how much things like evolution actually exist in the DCU.
    – Broklynite
    Apr 15, 2016 at 11:39
  • This assumes that Kryptonians never had any technology that allowed them to shape their own genetic evolution. Jan 17, 2019 at 1:49

The Why of Laser Eyes

Between 80 and 90 percent of undersea life has some form of bioluminescence according to Edith Widder's TED Talk, "Glowing Life in an Underwater World" which means that as far as life on Earth is concerned, the emanation of radiation is predominant. The rule rather than the exception. Life finds the transmission and reception of waves as incredibly valuable, whether sound waves or light waves or other electromagnetic spectrum segments. Butterflies can position themselves globally for their annual migration simply using internal biological clocks and the position of the Sun over the horizon... that one point of EM data translated into a precise satellite-free GPS that fits in the pinhead of a butterfly's neural network.

Focused or targeted waves have even more utility. It's why sound waves became predominate on land and why bioluminescence took over undersea. It adds communication and more to the ability. It is, in fact, possible to create a biological laser. A laser increases transmission distances and intention.

Humanoid creatures have the evolutionary advantage of large scale flexible cooperative coordination. Insects have large scale coordination but are inflexible... they can act only in relatively narrow programmatic parameters. Higher order animals show far more flexibility, but fall apart if attempting large scale coordination... nothing on the order of insects. Humanoids, however, are able to entertain and maintain abstractions (like law, religion, community, etc) through communication and language.

Imagine a species which gains the ability to telecommunicate over line-of-sight through laser light. They would be able to coordinate over greater distances, faster, more complex ideas (than shouting, smoke signals, etc) and evolve greater and faster sophistication sooner with less conflict. Those able to communicate over longer distances, faster, with more intensity and accuracy are selected and the laser vision gets better and better.

The next step and adaptation for humanoids is learning to cook one's food. Instead of being entirely obsessed with the acquisition of one's daily calories, the advent of cooking frees more calories per eating instance, which accordingly frees time to ruminate, invent, innovate, and create a role of intelligence. The advanced communicators already had an evolutionary advantage of coordinating with other groups, warding off competition and predators, and corralling prey in exhausting marathon hunts where herds found themselves cut-off by lightspeed maneuvers until run ragged, captured and eaten by the fledgling Kryptonians.

At one time or another, a Kryptonian decides to flash his eyes at his food and finds that he's stronger for it. Evolution begins to select for more intense, hotter, more powerful eyes for cooking, above and over, what's necessary for communication. Such selection isn't undermined by technology (the advent of fire) because it's still an integral part of their hunting, feeding, community, culture. Soon Kryptonians are self-selecting for laser strength above and beyond what nature would do and it becomes selectively bred to an obscene degree.


The simplest answer is that they did not evolve in the usual sense. That is, they were not selected for over multiple generations by natural selection.

Instead, these powers are byproducts of Kryptonian biology, and do not manifest themselves on Krypton. It is only under yellow suns that they become apparent, and Kryptonians did not evolve under these conditions. That they exist at all on earth can only be called a happy accident. (Happy for the comic writers, that is.)

There are other examples of such accidents. The use of inert gases such as xenon as anesthetics springs to mind. Human evolution did not include selection for such a reaction, yet it occurs nonetheless.

  • I've always believed that at their core Kryptonians were simply energy manipulators. Flight, heat vision, x-ray vision, there invulnerability aura, etc. are all by-products of their ability to manipulate energy fueled by the proper colored stars.
    – MrInfinity
    Dec 22, 2022 at 16:37

Lex's explanation is actually close to the one given by Superman's parents in the 1978 film. His resistance, strength, and ability to jump high (specifically, they explained he would only "seem" to fly) are due Earths's gravity being lower than Krypton. In early stories, he didn't have the ability to fly and only gained "true flight" once writers stopped trying to explain his powers based on Krypton's high gravity.

I guess what I'm getting at is that writers have given him a bunch of arbitrary powers -- flight, eye stuff, Sunny D -- and have sometimes attempted to explain them, but I do not believe that a sufficient explanation has ever been given that is in line with our current understanding of how evolution works.

  • He simply finally learned how to forget to fall.
    – RDFozz
    Jan 17, 2019 at 17:03

There's an argument here that it's NOT an evolutionary issue, per se.

In the golden-age/very early silver-age version of Superman's origin, Kryptonians have x-ray vision on Krypton. There's a scene in the origin where Jor-El says he wants to send the populace to Earth, and the science council jokingly remarks that Earthlings are so backwards "They do not even have x-ray vision!" But that reference has long since fallen away, and Kryptonians have no such amazing powers on their home planet, under their native red sun.

The evolutionary difference that Kryptonians have is the ability to absorb solar radiation. On Earth, that ability is "super-charged" and they absorb a far larger amount from our yellow sun. Heat vision is the rapid expelling of that energy through the eyes. There's a few theories about how x-ray version works, and they're probably not germane to the conversation, but it too is an "energy power" not strength, and so is connected to the use of the extra solar energy absorbed.

So, the question is how the ability to absorb solar radiation evolved. The relative weakness of the red sun is the the most obvious idea here. A weaker source means a greater need to absorb its energy. Humans don't absorb solar radiation in any direct way, but it's used to create vitamin D. Kryptonians simply work differently, they require solar energy more directly, so they evolved a more efficient way to do do, pretty much across the entire biosystem. And so any Kryptonian being who comes to Earth gets super-powers from the sun.


Superman's abilities stem from being born on a planet with more gravity. Superman doesn't have super strength, it just appears that way under Earth gravity, much as a human would appear to be super strong on the Moon.

As for his speed, this also seems to be affected by Earth gravity. Kal-El becomes a lot lighter under our gravity, and if you weigh less, you can not only run faster, but it also becomes a lot easier.

Superman's endurance might be a direct result of Kryptonian animals being just as vile and tenacious. An increase in strength, endurance and durability would be necessary for survival in such harsh environments, at least from our perspective.

As for the heat vision, the planet Krypton might have at one point have been highly radiated, and when intelligent life formed, they needed a way to release harsh contaminants from their system, hence heat vision.

Flying might be a by-product of Earth gravity, but also a result of his increased strength and the fact that he weighs less, flying becomes almost second nature. Honestly, from an evolutionary standpoint, he shouldn't be able to fly unless his bones were hollow like a bird.

Kryptonian cells were made to metabolize solar radiation, but on Krypton they can't get enough energy in their cells for their unique advantage, but on Earth the radiation becomes encouraged with it, leading to what would seem like extraordinary abilities. Or more realistically, Kryptonians have these abilities on Krypton, it just isn't as severe on Krypton. Again, because of gravity, everything becomes lighter to him and daily tasks become so easy he hardly breaks a sweat.

As for his x-ray vision, it might have been needed to spot predators in harsh environments (like a radiation storm) making it difficult to see or to spot predators behind tall grass. And the rest of his sight-related abilities (except heat vision) might fall into this category.

  • 1
    So you're saying that heat vision removes "contaminants" from their bodies? And X-ray vision evolved in response to predation? These reasons seem extremely speculative; can you provide any evidence that either of these is true?
    – DavidW
    Sep 10, 2021 at 3:57

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