# Incest and animals **URL:** \ **Category:** Factual Questions\ **Created:** [October 1, 2011, 1:23am UTC](https://boards.straightdope.com/t/incest-and-animals/598215 "2011-10-01T01:23:42Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [October 1, 2011, 1:23am UTC](https://boards.straightdope.com/t/incest-and-animals/598215/1 "2011-10-01T01:23:42Z")
Hello Everyone, I was looking at my dog today and of course I had a twisted though. Do animals participate in incest in the wild? The reason that I ask is that dogs (at least in my experience with my dogs) don’t seem to engage in sexual intercourse until the female is in heat. Then look out because every dog within 6 miles is trying to mate3 with her. If a female dog goes into heat will her offspring attempt to mate with her? Or how about a sister dog from the same litter or even a different litter? Humans generally don’t have incest because we have been taught that it is wrong. I wonder if we hadn’t been taught that would we, and animals of course don’t have morals and social stigma to prevent them from doing things like licking their balls, smelling each others asses. So, do they know it’s wrong and they don’t do it or if a female is in heat do they not care if it is mom or sister? ---
**Author:** ![zombywoof](https://avatars.discourse-cdn.com/v4/letter/z/9e8a1a/32.png) [@zombywoof](https://boards.straightdope.com/u/zombywoof)\ **Post date:** [October 1, 2011, 1:28am UTC](https://boards.straightdope.com/t/incest-and-animals/598215/2 "2011-10-01T01:28:37Z")
I don’t know how inbred wolves and the like get in the wild, but FWIW it’s not uncommon for dog breeders to breed “mother/son”, “father/daughter”, “sister/brother”, etc. pairs. ---
**Author:** ![Skald\_the\_Rhymer](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)\ **Post date:** [October 1, 2011, 1:45am UTC](https://boards.straightdope.com/t/incest-and-animals/598215/3 "2011-10-01T01:45:02Z")
> [@obbn](#): > > Hello Everyone, > I was looking at my dog today and of course I had a twisted though. Do animals participate in incest in the wild? The reason that I ask is that dogs (at least in my experience with my dogs) don’t seem to engage in sexual intercourse until the female is in heat. Then look out because every dog within 6 miles is trying to mate3 with her. If a female dog goes into heat will her offspring attempt to mate with her? Or how about a sister dog from the same litter or even a different litter? > Humans generally don’t have incest because we have been taught that it is wrong. I wonder if we hadn’t been taught that would we, and animals of course don’t have morals and social stigma to prevent them from doing things like licking their balls, smelling each others asses. So, do they know it’s wrong and they don’t do it or if a female is in heat do they not care if it is mom or sister? I’ve certainly seen hamsters doing it without regard to genetic closeness; I’d be simply shocked if wolves, lions, & such didn’t do it as well. Incidentally, I think the word you want is _inbreeding_. _Incest_ refers to sexual relations between persons too closely related to legally marry. It cannot apply to sex between animals, or so it seems to me. ETA: [Wikipedia is helpful here.](http://en.wikipedia.org/wiki/Inbreeding#Results) ---
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [October 1, 2011, 2:01am UTC](https://boards.straightdope.com/t/incest-and-animals/598215/4 "2011-10-01T02:01:48Z")
> [@Skald\_the\_Rhymer](#): > > want is _inbreeding_. _Incest_ refers to sexual relations between persons too closely related to legally marry. It cannot apply to sex between animals, or so it seems to me. > > ETA: [Wikipedia is helpful here.](http://en.wikipedia.org/wiki/Inbreeding#Results) You are correct, thanks for pointing that out. That was the word I was searching for, but had a brain fart and couldn’t come up with it. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [October 1, 2011, 2:12am UTC](https://boards.straightdope.com/t/incest-and-animals/598215/5 "2011-10-01T02:12:25Z")
There are actually some species of insects where brother-sister or mother-son incest is the _norm_. Female Komodo dragons can produce sons without requiring a male, all of which will be male, and can then have sex with their sons to produce more dragons. This is helpful for island-dwelling lizards where a lone female may become stranded on a new island without any other dragons, allowing her to establish a new colony all on her own. Among mammals such matings are not obligatory, but can and do occur. So the answer to the OP is definitely yes. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [October 1, 2011, 3:39am UTC](https://boards.straightdope.com/t/incest-and-animals/598215/6 "2011-10-01T03:39:25Z")
> [@obbn](#): > > If a female dog goes into heat will her offspring attempt to mate with her? Or how about a sister dog from the same litter or even a different litter? Oh hell yeah. Dogs have no concept of incest. > [@](#): > > Humans generally don’t have incest because we have been taught that it is wrong. Probably not true Certainly unsupported by fact. Humans avoid having sex with individuals whom they spend more than about 8 hours a day with during puberty. That’s hardwired in our brains, it’s not something that we are taught. Adopted siblings or children raised in group facilities such as orphanages have sex far, far less frequently than would be expected by random chance, to the point where it is is almost unheard of. It seems more likely that humans started teaching that incest is wrong ebcause of the biological imperative, rather than the opposite. > [@](#): > > …animals of course don’t have morals and social stigma to prevent them from doing things like licking their balls, smelling each others asses. Not like we humans, who stick out forelimbs into the genital openings of others and scape faeces of our buttocks with leaves. Yes, we certainly have the higher morals. 😃 ---
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [October 1, 2011, 1:09pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/7 "2011-10-01T13:09:13Z")
> [@zombywoof](#): > > I don’t know how inbred wolves and the like get in the wild, but FWIW it’s not uncommon for dog breeders to breed “mother/son”, “father/daughter”, “sister/brother”, etc. pairs. True. My dogs’ breed, [American Hairless Terriers](http://ahts.net/breed_history1.htm), were started from one hairless female, Josephine, who was mated once to her sire and once to one of her sons. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [October 1, 2011, 1:55pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/8 "2011-10-01T13:55:46Z")
> [@Blake](#): > > … Not like we humans, who stick out forelimbs into the genital openings of others and scape faeces of our buttocks with leaves. Yes, we certainly have the higher morals. 😃 Actually, the leaf thing is a moral imperative. Humans evolved the massive muscles of the buttocks to allow us to run efficiently in an upright posture. As a result, man is the only animal that has to wipe its ass. (Unless you count those messy sheep in New Zealand, but wait, we bred them that way…) As for the limbs, well we have the tools, why not use them? Dogs have no such advantage, so must use their noses and stick their face in each others’ genitalia… Oh wait, humans do \*THAT \*too. Actually, that brings up another interesting variation. Some monkeys and apes will masturbate, I understand - thus suggesting they get pleasure from the activity. The reason humans use their forelimbs on others is to provide sexual pleasure for partner(s) outside of regular intercourse. Any examples of this “sensitive new age man” behaviour in the wild kingdom? ---
**Author:** ![Capitaine\_Zombie](https://avatars.discourse-cdn.com/v4/letter/c/e95f7d/32.png) [@Capitaine\_Zombie](https://boards.straightdope.com/u/Capitaine_Zombie)\ **Post date:** [October 1, 2011, 3:45pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/9 "2011-10-01T15:45:01Z")
Darn, with this thread title, I was hoping for some links… ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [October 1, 2011, 4:02pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/10 "2011-10-01T16:02:41Z")
[Here’s](http://ags.kku.ac.th/Monchai1/Teaching/PopGen/Paper/Inbreeding%20Avoidance.pdf) a review article on the significance of inbreeding depression in animals, as well as mechanisms that have evolved to avoid it. There is good evidence that many animals will avoid mating with close relatives, probably to avoid the potential problems caused by inbreeding. Many primates will avoid mating with siblings or other relatives out to the level of first or even second cousin. Studies of other species suggest avoidance of siblings, littermates, or nestmates. The mechanism may vary. Some animals may directly recognize relatives by scent (or at least, reject individuals that smell like they might be relatives). In others, as apparently in humans, the mechanism is social, in that individuals don’t find those that they have been raised with attractive as mates (even if unrelated genetically, as in the case of step-siblings or adoptees). On the other hand, humans seem unable to recognize relatives that they have been raised apart from purely by physical cues. ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [October 1, 2011, 4:17pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/11 "2011-10-01T16:17:32Z")
> [@Skald\_the\_Rhymer](#): > > I’ve certainly seen hamsters doing it without regard to genetic closeness; I’d be simply shocked if wolves, lions, & such didn’t do it as well. I don’t think you can make such an observation about captive animals’ behaviour and extrapolate to that of wild ones. A caged pet’s choice of sexual partners is limited to whoever is sharing their enclosure; their sex drive may be stronger than any natural aversion to mating with their close relatives. It may well be that in the wild they would avoid mating with close relatives, either due to some innate revulsion or to the improbability of meeting them in their wider habitat range. ---
**Author:** ![Capitaine\_Zombie](https://avatars.discourse-cdn.com/v4/letter/c/e95f7d/32.png) [@Capitaine\_Zombie](https://boards.straightdope.com/u/Capitaine_Zombie)\ **Post date:** [October 1, 2011, 4:35pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/12 "2011-10-01T16:35:06Z")
> [@psychonaut](#): > > I don’t think you can make such an observation about captive animals’ behaviour and extrapolate to that of wild ones. A caged pet’s choice of sexual partners is limited to whoever is sharing their enclosure; their sex drive may be stronger than any natural aversion to mating with their close relatives. It may well be that in the wild they would avoid mating with close relatives, either due to some innate revulsion or to the improbability of meeting them in their wider habitat range. You mean that’s like prison hamster sex? ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [October 1, 2011, 6:33pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/13 "2011-10-01T18:33:16Z")
> [@Broomstick](#): > > There are actually some species of insects where brother-sister or mother-son incest is the _norm_. > > Female Komodo dragons can produce sons without requiring a male, all of which will be male, and can then have sex with their sons to produce more dragons. This is helpful for island-dwelling lizards where a lone female may become stranded on a new island without any other dragons, allowing her to establish a new colony all on her own. > > Among mammals such matings are not obligatory, but can and do occur. > > So the answer to the OP is definitely yes. This is fascinating. So the females can have offspring with no sex, but those offspring are all male? But if sex is involved, then the offspring can be male or female? How does fertilization happen without intercourse? Do they just crank out male offspring constantly? ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [October 1, 2011, 6:37pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/14 "2011-10-01T18:37:35Z")
> [@obbn](#): > > Humans generally don’t have incest because we have been taught that it is wrong. I disagree with this. I don’t think that there are many guys that walk around thinking that they would love to bang their sisters, but damn, it’s immoral to do so, therefore I must refrain. We’ve been taught that adultery is wrong, but you see how prevalent that is. There is definitely something hardwired in our brains that turns off whatever attracts us to closely related to members of the opposite sex. I suppose that, objectively speaking, both of my sisters are good looking girls, but I have never had the beginnings of a sexual attraction towards them. It’s like a switch in your brain that gets turned to the off position. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [October 1, 2011, 6:47pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/15 "2011-10-01T18:47:12Z")
> [@jtgain](#): > > This is fascinating. So the females can have offspring with no sex, but those offspring are all male? > > But if sex is involved, then the offspring can be male or female? Komodo dragons use a different sex determination system than mammals do. In Komodo dragons the sex chromosomes are designated Z and W. The ZW configuration makes a female, the ZZ makes a male. Since a female dragon has both sex chromosomes they can generate eggs with both kinds. There’s a complicated bit involving duplicating the chromosomes to get a full set, after which the ZZ eggs make male dragons and the WW’s just fail to develop at all (one tip off in zoos that a lady dragon has done this is only half the eggs in a clutch hatching). After the ZZ boys grow up mom has sex with them to produce a normal crop of ZW girls and ZZ boys for the next generation. Birds also use a ZW sex chromosome system, so girl birds are ZW and boy birds ZZ. > [@](#): > > How does fertilization happen without intercourse? Do they just crank out male offspring constantly? I don’t think anyone knows for sure. Given that komodo dragons will happily eat humans as well as other critters studying them isn’t always easy. The ones that have done this in zoos all seem to have gone 2-3 years without contact with a male, so maybe it’s that lack of such contact that triggers the parthenogenesis. It apparently has also happened in the wild, but even less is known of the mechanism there. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [October 1, 2011, 7:03pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/16 "2011-10-01T19:03:18Z")
> [@psychonaut](#): > > I don’t think you can make such an observation about captive animals’ behaviour and extrapolate to that of wild ones. A caged pet’s choice of sexual partners is limited to whoever is sharing their enclosure; their sex drive may be stronger than any natural aversion to mating with their close relatives. It may well be that in the wild they would avoid mating with close relatives, either due to some innate revulsion or to the improbability of meeting them in their wider habitat range. True. In the case of dogs, most breeds are the result of close inbreeding, so any mechanisms that prevent mating with close relatives in wolves have probably been selected against in producing them. ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [October 1, 2011, 7:31pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/17 "2011-10-01T19:31:05Z")
> [@jtgain](#): > > There is definitely something hardwired in our brains that turns off whatever attracts us to closely related to members of the opposite sex. Yes, and it’s not just the genetic relation; IIRC studies have been done on Israeli kibbutzim which found that unrelated children who grow up there together are, upon reaching adulthood, just as averse to mate with each other than they are with their blood relatives. Evidently there’s something in our genetic programming which disinclines us to have sex with the people we grow up in the same household with. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 1, 2011, 7:38pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/18 "2011-10-01T19:38:03Z")
Other animals will often have other behavorial mechanisms to prevent it, such as all the males but one being forced out of the pride/pack/whatever of their birth. And of course, non-social animals with a large range are unlikely to meet their close relatives again just by virtue of statistics. ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [October 1, 2011, 8:22pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/19 "2011-10-01T20:22:16Z")
> [@psychonaut](#): > > Yes, and it’s not just the genetic relation; IIRC studies have been done on Israeli kibbutzim which found that unrelated children who grow up there together are, upon reaching adulthood, just as averse to mate with each other than they are with their blood relatives. Evidently there’s something in our genetic programming which disinclines us to have sex with the people we grow up in the same household with. Interesting. I wonder if the opposite is true. Let’s say that you had a secret sister that your parents gave up for adoption when she was young. Would that guy (assuming they met under random circumstances later in life) have a sexual attraction towards her, or would there be some “magic,” if you will, inside him that would tell him that was his sister and that she was off limits.. ---
**Author:** ![Filbert](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/filbert/32/3433_2.png) [@Filbert](https://boards.straightdope.com/u/Filbert)\ **Post date:** [October 1, 2011, 9:43pm UTC](https://boards.straightdope.com/t/incest-and-animals/598215/20 "2011-10-01T21:43:06Z")
> [@jtgain](#): > > Interesting. I wonder if the opposite is true. Let’s say that you had a secret sister that your parents gave up for adoption when she was young. Would that guy (assuming they met under random circumstances later in life) have a sexual attraction towards her, or would there be some “magic,” if you will, inside him that would tell him that was his sister and that she was off limits.. No magic, I’m afraid- I’ll try and find the research I read, but basically people tend to be attracted to folks similar to those they grew up with, just not the _same_ people. Which has an unfortunate side effect that people are generally quite likely to be attracted to ‘lost’ family members. The tendency to feel no attraction to those you’re brought up with is known as the [Westermarck Effect](http://en.wikipedia.org/wiki/Westermarck_effect). A lot of animals do inbreed, though a lot of species do have various mechanisms in place to reduce this. Male chimps seem to show a marked tendency to avoid mating with their mother, and I think female siblings- it has been observed in a number of primate species. Other animals who don’t show this behaviour, as has been said above, have a society where all ‘spare’ males (or females) leave the group- or only one dominant pair are allowed to breed. [Next page](https://boards.straightdope.com/t/incest-and-animals/598215.md?page=2)