This one is kind of short. We know of natural materials that can interfere with IR, such as a polar bear's fur which, along with its blubbers, makes them nigh invisible on thermal cams. The TL; DR version is that the fur reflects IR radiation, back into the bear, and ambient radiation away from it, making polar bears a natural counter to the Predator.

So, suppose I have quite a few animals that can effectively be targeted by radar, meaning they fly, usually high. I need something light that living creatures can naturally produce and is able to absorb the radio waves from the range that radars use. Is there such material?

Note, the animal in question is about as tall as a giraffe. While there is no upper limit, they should at least be good enough to remain undetected by early warning radars.

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  • $\begingroup$ How big are these creatures? Single birds of any size don't usually show up on radar, but large flocks can. It might matter for the question if these are aircraft size lone birds, or flocks of smaller birds. $\endgroup$
    – AndyD273
    Commented Oct 28, 2020 at 18:30
  • $\begingroup$ @AndyD273 The Hatzegopteryx Thambena $\endgroup$ Commented Oct 28, 2020 at 18:31
  • $\begingroup$ Most animals have a poor radar signature to begin with compared to metallic aircraft. That said, no material will make you 100% invisible to radar, just reduce how far away you can be spotted. So, you might want to consider adding some details about just how stealth your animal needs to be. $\endgroup$
    – Nosajimiki
    Commented Oct 28, 2020 at 18:51
  • $\begingroup$ "The range that radars use" is huuuge, from tens of megahertz to tens of gigahertz and more (wavelengths from about 10 m to down to millimeters). I seriously doubt that there is any material which would be equally effective for all the various kinds of radar. (Even the famed American "stealth" aircraft are stealthy only for some kinds of radar, being optimized for slealthiness on the kind of targeting radar common on fighter planes and x-to-air missiles of the time.) (And individual animals are already hard to spot on radar, being non-metallic in nature and very poor reflectors.) $\endgroup$
    – AlexP
    Commented Oct 28, 2020 at 19:26
  • $\begingroup$ A large part of "Stealth" aircraft, is about reflecting the radar away from the sender. Thats why they have all those sharp edges. (Think of it like you reflecting a laser in a mirror. if you're not 90 degrees to the mirror, the laser ends up somewhere else and you don't know the laser hit the mirror) $\endgroup$ Commented Oct 29, 2020 at 7:33

1 Answer 1


There is a fish (pacific blackdragon) that may be of some interest, it's skin adsorbs 99.95% of the light the hits its skin. It adsorbs so much light because it arranges light adsorbent compounds (melanin) into a larger structure that reflects the light back and forth in it, increasing the number of times the light hits the adsorptive compound. While melanin doesn't adsorb radar, this larger structure is being researched for radar adsorbent materials, when combined with a radar adsorbent material.

A material that has been used as a radar adsorbent material is magnetite, it is also produced biologically in some birds, bacteria, and molluscs, birds use it in they detection of the earths magnetic field.

So your creature may have clusters of magnetite, arranged so that the radar reflects back and forth, in the material, to maximise absorbance of the radar.

Hopefully that helps.

  • $\begingroup$ Sounds good to me. $\endgroup$ Commented Oct 29, 2020 at 8:40

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