I live in Cambridge, UK, and found these mites (probably? not sure) in the attic. There are no bird nests at or around the dwelling, and no traces of rats or mice. There are plenty of those and not clear what they feed on. Body is about 0.7-1mm long, see photo with a ruler for scale.

Can you please help identifying these?

mite species photo

  • $\begingroup$ Welcome to Biology.SE. Can you be a bit more specific about where in the UK? This information may not be needed, but since conditions in the Shetlands and Wales (for example) are a quite different that information may help pin down your mite. $\endgroup$
    – tyersome
    Aug 29, 2021 at 17:32
  • $\begingroup$ Thanks - updated (Cambridge, UK) $\endgroup$
    – abbot
    Aug 29, 2021 at 17:49
  • $\begingroup$ Great! If you don't get an answer I encourage you to check out some of the websites such as iNaturalist that specialize in identifications. If you do find an answer elsewhere it would be great if you would post an answer here that includes: discussion of key features that led to the identification, and supporting references or validated images! $\endgroup$
    – tyersome
    Aug 29, 2021 at 21:43
  • 1
    $\begingroup$ In support of Acari, there doesn't seem to be any division on the scute or any elytra, so it is unlikely to be a beetle. Also no obvious separation in to head, thorax, abdomen, though you might only see this on upside-down ones. $\endgroup$
    – bob1
    Aug 30, 2021 at 21:56

1 Answer 1


This is a mite in the order Oribatida. Like many other oribatids, it appears to be covered with a smooth, dark, hardened, vaguely teardrop-shaped "shell", like a beetle—hence the common name "beetle mites". Its mouthparts and legs, visible at the narrower front end, are flanked by thin, flat plate-like structures called pteromorphs ("wing-shaped"), which you can also see in this photo and this SEM image. It is also the right size for an oribatid (visible to the naked eye, under 2mm).

David E. Walter notes in his key that there are similar heavily armoured mites in other groups. Most of the characteristics that are only found in oribatids, like long sensory hairs just behind their "head", can only be seen with much higher magnification. But I am reasonably confident this one is an oribatid and not a mesostigmatid/prostigmatid mite because of the combination of smooth, shiny hard shell, leg and mouthpart placement, and pteromorphs.

These tiny, harmless mites live in soil, under rocks, etc. Further identification usually requires an expert with a microscope. If you are on Twitter, the British Arachnological Society may be able to hook you up with a mite expert.

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    $\begingroup$ Please update your answer to explain/describe why these are Orbitid mites. How can you tell? What evidence do you have? Thanks $\endgroup$ Oct 1, 2021 at 20:06
  • $\begingroup$ Amazing, thank you! $\endgroup$
    – abbot
    Oct 8, 2021 at 11:11

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