Deer Louse

2013 February 9

Sandy likes to hunt. And the deer like to eat our fruit trees. So Sandy hunts the deer that come into our backyard, so that we can eat them. This past year, she shot one during archery season[1], on October 14, 2012. After helping her gut it and drag it out of the woods, I then obviously[2] had to check for deer-specific parasitic arthropods, so I went over the body with a nit-comb to see what would turn up. Kind of surprisingly, I didn’t find much[3], but several attempts finally turned up this:

It’s only about two millimeters long. For scale, that transparent cylindrical object running across the top of the picture is the deer hair that the louse was found clinging to.

From the big head and the comparatively powerful jaw muscles, this looks to be one of the chewing lice (Mallophaga).

Searching on the terms “White-tailed deer” and “lice”, it looks like the most common chewing lice on deer are in the genus Tricholipeurus. I’d say it’s probably Tricholipeurus parallellus, because it looks like the other common species tend more towards the semi-tropics and are rarely found this far north. When living on a warm-blooded animal like a deer, they would be able to survive freezing temperatures just by burrowing deep into the fur or hanging out in places like the armpits and behind the ears. And they would generally jump directly from a mother to her babies, so they wouldn’t ever have to spend much time completely exposed to the elements. But even so, it would get pretty cold when the outdoor temperatures drop to around zero Fahrenheit, so the local deer lice would need some degree of cold-tolerance. Especially if deer also tend to roll in the snow when they get itchy (which I think they do).

[1] Now that crossbows are legal for general hunting use in Michigan, she can actually hunt during archery season with a reasonable chance of success.[4] See, the problem with standard bows is that they are difficult to aim properly. And to be sure of killing a deer quickly, you need to hit a spot roughly the size of a dinner plate. So, even after practicing daily for weeks, the average person has to sneak up pretty darned close to the deer (probably 50 feet or less) in order to be reasonably certain of hitting the vital spot with a standard bow. And at that distance, they notice you. Reliably hitting the vital spot is important, because if you miss it, the result is a wounded deer that may take hours or days to die. Which is needlessly cruel, and also usually results in the deer dying somewhere that it won’t be found by anyone other than the coyotes. A crossbow, on the other hand, is dramatically easier to aim accurately than a standard bow[5]. So, using one she can shoot a deer from just far enough away that the deer is surprised, while still having a very high probability of hitting the vital spot (so far, she’s 2 for 2 with the crossbow).

[2] Hey, it’s me. Of course I have to do this. It occurs to me that if I want to get a reputation as a local weirdo (as opposed to being merely eccentric), I could probably go to the county fair next year and ask everybody if I can comb their livestock for lice. Although, if I go in with an official-looking data form, have pre-labeled sample bottles, and say I’m from the University (which isn’t even a lie!), I’d most likely be able to do it without even raising many eyebrows.

[3] Sandy also spotted a loose deer tick while she was field-dressing the deer, but we were both too occupied with other things at the time to collect it. And the one she found while skinning the skull[6] was engorged, and we already have pictures of engorged deer ticks.

[4] The incentive for hunting with a bow and arrow (or, now, a crossbow) is that it is legal to shoot any adult deer during archery season, but during rifle season you can only shoot bucks unless you have a special doe permit. Doe permits are only available in particular regions, and for some reason the state never issues them for the side of the highway that we live on (although they issue them for the other side of the highway). In spite of the fact that there is a continuous stream of does traipsing across our yard all the time trying to gnaw down our young fruit trees.

[5] The story of William Tell shooting an apple off of his son’s head with a crossbow bolt may have been at least partly an early advertising pitch for the superior accuracy of the crossbow compared to a regular bow.

[6] Sam has kind of a fascination with skeletons at the moment, so we are extracting the deer skull for her. We also have a couple of dead mice and a frog being consumed by dermestid beetles to expose their skeletons, but this could take a bit of time.

2 Responses
  1. Carmen permalink
    October 10, 2016

    Came across your blog after a Google image search for “deer lice” brought up some photos that linked me here. I’ve got to say I quite enjoy the blog itself and you have so e damn good photos of the little buggers, what type of camera do you use ? If you mentioned it in another post I apologize for asking, I haven’t read the post yet if you have.
    In regards to being the weirdo….so am I. I am equally fascinated as disgusted by lice, fleas, ticks and all manner of blood sucking anthropods. I am known to carry flea combs with me when I got onto my friend’s homes and completely comb every inch of the animals they have. Usually their animals are loaded with these disgusting insects and are thankful yet grossed out that I’d willingly subject myself to them.
    The idea of knowing that there are biting, itchy disease caring bugs right beside me living in carpets and causing these animals distress annoys me to no other.
    Anyway, I apologize for the story just want you to know combing other people’s livestock doesn’t make you weird; weird means uncommon and our paticular activity is on a lot of people’s to do lists.
    For fun check out Google suggestions when you type in flea picking. Hundreds of thousands of people admitting to picking fleas off animals and enjoying the heck out of it.
    Final thought, I live in northern California in the shasta – trinity-siscquio forest just 45 minutes away from the Pacific and we have all sorts of weird critters out here.
    Thank you for the enjoyably fun read.

  2. October 10, 2016


    Information about my photography setup is here,, and is also linked through the “macrophotography on the cheap” tab up at the top of this page. Basically it is a Canon 10D digital SLR with a 100 mm F2.8 macro lens, and for this shot it also had a reversed 50 mm lens screwed onto the end to boost the magnification. The flash uses a homemade white cardboard cone to concentrate the light onto the subject.

    And thanks for the comments!

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