# Maggots eat only dead flesh? **URL:** \ **Category:** Factual Questions\ **Created:** [December 3, 2008, 12:25pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494 "2008-12-03T12:25:43Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [December 3, 2008, 12:25pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/1 "2008-12-03T12:25:43Z")
I often see the statement made that maggots only eat dead flesh. Do maggots absolutely never eat healthy flesh, or is it just a general rule that they don’t? Will a starving maggot go without food rather than switch to healthy flesh? ---
**Author:** ![KarlGrenze](https://avatars.discourse-cdn.com/v4/letter/k/dbc845/32.png) [@KarlGrenze](https://boards.straightdope.com/u/KarlGrenze)\ **Post date:** [December 3, 2008, 12:33pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/2 "2008-12-03T12:33:35Z")
Maggots are the larval stage of flies. Mommy fly will not deposit the eggs in a place she finds unsuitable for raising her young, I’d think. 😉 Oh, and the animal does not have to be dead, just the place where the maggots live has to be necrotic. Think nasty untreated infected wound. And of course, without treatment, that area may get bigger and bigger, but the maggots themselves are feasting on the dead part, not burrowing their way into the still viable flesh left. There are a couple of flies whose larval stages can and will eat healthy, non necrotic flesh. One of them is Cochliomya omnivorax, a foreign parasite to the United States. There have been a couple of cases in which animals travelling abroad have come back with their larvae, but luckily all the maggots were removed before they grew up and reproduced, so they were not reintroduced to the environment. ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [December 3, 2008, 12:59pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/3 "2008-12-03T12:59:58Z")
I don’t have any cites handy, but I’m certain that maggots are sometimes used to clean wounds on humans. Maybe it was experimental? I guess it wouldn’t be much different than using leeches to maintain blood flow in reattached fingers. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [December 3, 2008, 1:01pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/4 "2008-12-03T13:01:02Z")
> [@Harmonious\_Discord](#): > > I often see the statement made that maggots only eat dead flesh. Do maggots absolutely never eat healthy flesh, or is it just a general rule that they don’t? Will a starving maggot go without food rather than switch to healthy flesh? [Given that surgical maggots are used to clean dead tissue from wounds](http://www.ncbi.nlm.nih.gov/pubmed/12471580), I’d say it’s a fairly strict rule. ([And modern physicians still use leeches.](http://journals.cambridge.org/action/displayAbstract;jsessionid=2FA954D14A205912A8CD980E39007288.tomcat1?fromPage=online&aid=1070716) There’s a distinct lack of coverage of black bile in Taber’s these days, though.) ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [December 3, 2008, 2:37pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/5 "2008-12-03T14:37:19Z")
I’m asking, because it’s used for cleaning up wounds and such. Will the maggots start eating healthy flesh when starving, because the hospital staff screwed up, and left them in place too long. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [December 3, 2008, 3:08pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/6 "2008-12-03T15:08:00Z")
[And a timely story](http://www.foxnews.com/story/0,2933,460915,00.html). I suspect the fact that the woman might not make it has more to do with the advanced condition of the sore than the presence of maggots. ---
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [December 3, 2008, 3:19pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/7 "2008-12-03T15:19:37Z")
> [@Harmonious\_Discord](#): > > I’m asking, because it’s used for cleaning up wounds and such. Will the maggots start eating healthy flesh when starving, because the hospital staff screwed up, and left them in place too long. I’ve always wondered this. How do they “know” to eat only dead tissue? ---
**Author:** ![AuntiePam](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@AuntiePam](https://boards.straightdope.com/u/AuntiePam)\ **Post date:** [December 3, 2008, 3:32pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/8 "2008-12-03T15:32:58Z")
Dead over live? Maybe the odor and the softer consistency make dead flesh more appetizing. ---
**Author:** ![KarlGrenze](https://avatars.discourse-cdn.com/v4/letter/k/dbc845/32.png) [@KarlGrenze](https://boards.straightdope.com/u/KarlGrenze)\ **Post date:** [December 3, 2008, 3:57pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/9 "2008-12-03T15:57:50Z")
I made a huge typo with my screwworm post… The correct name is Cochliomyia hominivorax, and [this](http://www.oie.int/eng/normes/mmanual/2008/pdf/2.01.10_SCREWW.pdf) is the OIE chapter on both this species (New World) and Old World screwworm. As it says there, unlike other types of flies, they specifically seek out live animals and lay eggs on their fresh wounds (or even undamaged skin, eek!). And unlike other flies which only feast on the rotting parts, these flies burrow deep into the living tissues, tearing them apart. All the while, they secrete odors that attract even more screwworm flies. Interesting reading, but it doesn’t deal with the other types of flies. From what I’ve read, it seems they are attracted to the smell of decaying matter (and feces). That’s why they lay their eggs there. A quote from the Merck Vet Manual regarding blowflies: > [@](#): > > Under normal conditions, adult flies of these genera lay their eggs in feces or in decaying animal carcasses. In facultative myiasis, the adult flies are attracted to a moist wound, skin lesion, or soiled hair coat. A common site is the breech, where flies may be attracted to wool soaked with urine or feces. As adult female flies feed in these sites, they lay eggs. The eggs hatch, producing larvae (maggots) that move independently about the wound surface, ingesting dead cells, exudate, secretions, and debris, but not live tissue. This condition is known as fly strike or strike. The larvae irritate, injure, and kill successive layers of skin and produce exudates. Maggots can tunnel through the thinned epidermis into the subcutis. This process produces tissue cavities in the skin that measure up to several centimeters in diameter. Unless the process is halted by appropriate therapy, the infested animal may die from shock, intoxication, histolysis, or infection. A peculiar, distinct, pungent odor permeates the infested tissue and the affected animal. Advanced lesions may contain thousands of maggots. Their presence can create additional injury, but the maggots themselves are not tearing the flesh apart. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [December 3, 2008, 4:00pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/10 "2008-12-03T16:00:35Z")
> [@toadspittle](#): > > I’ve always wondered this. How do they “know” to eat only dead tissue? How do you “know” not to eat poop? ---
**Author:** ![Rdy2srvher2](https://avatars.discourse-cdn.com/v4/letter/r/ee59a6/32.png) [@Rdy2srvher2](https://boards.straightdope.com/u/Rdy2srvher2)\ **Post date:** [November 1, 2011, 10:02pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/11 "2011-11-01T22:02:05Z")
For both the Common Housefly and it’s larvae (maggot) the way they eat is by drinking! They release enzymes that liquefy the dead and decaying material then drink it up. They can’t eat live flesh because the enzymes can’t liquefy it. ---
**Author:** ![Rdy2srvher2](https://avatars.discourse-cdn.com/v4/letter/r/ee59a6/32.png) [@Rdy2srvher2](https://boards.straightdope.com/u/Rdy2srvher2)\ **Post date:** [November 1, 2011, 10:03pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/12 "2011-11-01T22:03:20Z")
BTW, the New World Screwfly is native to the southern US. However it was eradicated here. ---
**Author:** ![toodlepip](https://avatars.discourse-cdn.com/v4/letter/t/97f17d/32.png) [@toodlepip](https://boards.straightdope.com/u/toodlepip)\ **Post date:** [November 1, 2011, 11:07pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/13 "2011-11-01T23:07:59Z")
[Greenbottle](http://http://en.wikipedia.org/wiki/Green_bottle_fly) maggots are used for maggot therapy because of their preference for necrotic tissue. It can be very successful. A friend of mine had the enviable title of “maggot nurse” in a UK hospital some years ago. According to her, most patients cope well with it as long as the maggots are covered and there are no escapees. :eek: In contrast, other types of blowfly maggots do not discriminate between healthy and necrotic tissue. [Fly strike](http://en.wikipedia.org/wiki/Myiasis) is a common, often fatal, problem in many species. Maggot therapy is used in the veterinary world, although I’ve never tried it. I’ve spent enough time picking and flushing them out of infected messy wounds, it just goes against the grain to shove more - albeit different - maggots in there. I have had some good results with leeches though, on one occasion saving a limb which we were resigned to amputating. ---
**Author:** ![AndrewL](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@AndrewL](https://boards.straightdope.com/u/AndrewL)\ **Post date:** [November 2, 2011, 12:40am UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/14 "2011-11-02T00:40:22Z")
But do flies eat zombies? ---
**Author:** ![GameHat](https://avatars.discourse-cdn.com/v4/letter/g/ed655f/32.png) [@GameHat](https://boards.straightdope.com/u/GameHat)\ **Post date:** [November 2, 2011, 1:27am UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/15 "2011-11-02T01:27:23Z")
I had always thought (no cite) that maggots used for medicinal purposes strongly prefer dead flesh and will preferentially eat that, but they aren’t gonna starve to death once the dead flesh is consumed. As in, they are used to clean necrotic tissue from a wound, but are removed promptly once the necrotic flesh is mostly gone. Otherwise they’d just keep eating _shudder_. ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [November 2, 2011, 1:00pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/16 "2011-11-02T13:00:42Z")
> [@GameHat](#): > > I had always thought (no cite) that maggots used for medicinal purposes strongly prefer dead flesh and will preferentially eat that, but they aren’t gonna starve to death once the dead flesh is consumed. > > As in, they are used to clean necrotic tissue from a wound, but are removed promptly once the necrotic flesh is mostly gone. Otherwise they’d just keep eating _shudder_. But there’s a limit to how much a maggot will eat before pupating; they only live 4-7 days and would probably pupate if they run out of food. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [November 2, 2011, 2:41pm UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/17 "2011-11-02T14:41:36Z")
BTW, the woman I linked to earlier did actually pull thru. Some type of fly is responsible for ocular myiasis (in living tissue), which is always interesting to watch on medical docs. ---
**Author:** ![joeish80829](https://avatars.discourse-cdn.com/v4/letter/j/e495f1/32.png) [@joeish80829](https://boards.straightdope.com/u/joeish80829)\ **Post date:** [August 1, 2015, 7:35am UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/18 "2015-08-01T07:35:12Z")
> [@Santo\_Rugger](#): > > How do you “know” not to eat poop? I felt that was a very intelligent comment about the poop, Santa! ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [August 1, 2015, 8:05am UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/19 "2015-08-01T08:05:23Z")
> [@GaryM](#): > > I don’t have any cites handy, but I’m certain that maggots are sometimes used to clean wounds on humans. Maybe it was experimental? It could have been… three hundred years ago when a French battlefield doctor started using maggots to clean wounds 😉 (actually, according to Wiki the practice is even [much older than that](https://en.wikipedia.org/wiki/Maggot_therapy)) It might not be true of _all_ maggots, but certainly there are species of flies whose larvae just don’t go in for healthy tissue, probably because of a consumption (can’t bite chunks off) or digestion (can’t process it) issue. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [August 1, 2015, 8:09am UTC](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494/20 "2015-08-01T08:09:30Z")
> [@AndrewL](#): > > But do flies eat zombies? Of course they do - they are, by definition, dead. [Next page](https://boards.straightdope.com/t/maggots-eat-only-dead-flesh/475494.md?page=2)