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[Tacomagic]

As some people have noticed, domestic animals are a bit dodgey on the whole breeding thing.  In an effort to get to the bottom of this I sacrificed utilized some dorfs to do some domestic animal breeding to see if I could find any patterns.

My first experiment is pretty free-form.  Mostly just a way to test the waters.

Experimental Setup:
I created a new 300 year medium world with 10k embark points but otherwise everything else based on the default Medium Region advanced generation setting.
I turned off Invasion and picked a low-savagry area so that I'd be left alone.  That was mostly successful until I had a vampire join the ranks midway through year 2.

I embarked with 3 proficient miners, 1 Proficient Farmer, 1 Proficient Cook/Brewer, and 2 Proficient hunters.
I used the basic loadout plus about 600 alcohol, 500 plump helmets, and some extra crossbows and ammo.

All that was to make sure my dwarves would survive the 2 years I needed for the experiment.

Domestic animal loadout included the following:
5 Dogs (1M/4F)
5 Cats (1M/4F)
5 Pigs (1M/4F)
5 Goats (1M/4F)
5 bunnies(1M/4F)
5 Blue Peas (1M/4F)

Upon embark I dug the most basic fort possible just to get the dorfs set up so that they would take longer than 2 years to die off.  Just basic industry craft shops to keep them fed and ward off strange moods when they struck, a single large farm set to plump helmets and a catch-all custom stockpile.

Goats and bunnies were put out in pastures, pigs were pastured inside, Peas were segregated into nestboxes and the male pastured alone, dogs and cats were allowed to run free, though the dogs mostly hung out at the meeting site.

At this point I basically just let the game run itself with only the occasional handling of strange moods and brewing tasks.  Basically I only really stepped in when I saw an animal birth so I could use the offspring to determine who gave birth and how many.

Findings:
This is the breakdown of sterility in my animal populations after the 2 elapsed years.

• Peas: 1 Sterile Female.  2 years of sitting on a nest, no chicks.  The other 3 produced one clutch of chicks each, but no further.  Probably because I didn't bother to remove the chicks from the nest enclosures.
• Cats: Harder to track because they run everywhere and it's hard to know where the kittens come from.  Best guess was that there was at least 1 sterile female, but probably 2
• Pigs: 1 sterile female: Pigs had 2 clutches of exactly 3 piglets, all timed within a few seconds of each other both births.  Best I can tell, one of the females is barren.
• Goats: Entire population sterile
• Dogs: Entire population sterile
• Bunnies: Upon reaching maturity, entire population appeared fertile.  And very fertile at that.  They out-bred everything else once they got going.

Analysis:
Single creture sterility was observed conclusively with the singular sterile Female Peahen.  This was also potentially observed in the pig population as well, since both clutches of pigletts were eactly 3 in number.  The other possibility is that a single male can only impregnate 3 females at a time.  However, I have to discount this possibility because the single Peahen remained infertile even with the other 3 birds not producing.  Further, early on a migration wave brought an additional Boar, so the ratio of males to females in the pig population was 1:2 for most of the experiment.  The final possibility is that only 3 creatures of any species can be pregnant at any one time.  Certainly a possibility, but that does not adequately explain the sterile Peahen unless the caged peachicks were causing issues.

Full population sterility of Goats and Dogs can be explained either by all the females being sterile or the singular male being sterile with an indeterminate number of sterile females.  This possibility will be covered in further work.

Finally, it is possible that brining baby animals on embark will produce 100% fertile populations.

Further Work:
The next experiment will involve much better control of variables.  For this experiment I'll be concentrating on seeing if whole populations go sterile at once, or if issues are stemming from male sterility in female-heavy populations.

• All female animals will be individually penned in pastures behind forbidden doors so as to precisely monitor births.
• Babies will be separated into cages after they are recorded to prevent any possible negative effect they have on nests or breeding in general.
• Goats will have to be penned outside in individual pastures.  This will be attempted without walling for this phase
• Larger populations will be brought with a 1:2 M:F ratio.  Populations will be 8 female and 4 male.  This should allow a much lower chance of failure due to the unlikelyhood of 4 sterile males IF the bug is truly random.
• Dwarf population will be capped at 20 to prevent the issues with migration experienced in the first round.  The hope is that this bug is not affected by dwarf population (it does not appear to be).
• The 3-at-a-time pregnancy theory will also be checked for with the numbers.
• Once again, basic dwarven needs will be met, but not much more than that.  No trading caravans either.

Future-Future Work:
Beyond the next experiment, I will be testing baby populations at embark.  Specifically trying to verify whether or not 100% fertility is realized from baby animals.  Most likely this will work with a similar setup as above, but with a full compliment of baby animals rather than adults.

I also want to test if chicks in the nest-box prevent additional clutches from hatching.  I've found no reference to this particular behavior, but it seems plausible.

NOTE: I will be uploading saves as I generate them to the current bug report for domestic sterility.

[Gigaz]

Isn't there a cap for the number of animals you can have before they stop breeding at all? That might easily explain why you see what you see. The bunnies multiply, leaving no room for other animals.

[Tacomagic]

Isn't there a cap for the number of animals you can have before they stop breeding at all? That might easily explain why you see what you see. The bunnies multiply, leaving no room for other animals.

So far as I know, the cap is 50 per species, which I never came close to with any species.  Also, the bunnies had a lag time of almost a year before their first kits were born (due to embarking with baby rabbits rather than full grown). During that year neither goats nor dogs bred, which indicates their sterility is unrelated to the rabbit population.  Of note: Pigs, cats, peas, and one of my wagon horses all bred at least once before the male rabbit grew to adulthood.   

Beyond that, even with my bunnies doing so well, there were still only about 25 of them by the end of the experiment, which really isn't that many, just more than any other animal population.  Finally, the last birth I had before the end of the experiment was 3 kittens, so I find it unlikely that the bunnies were causing breeding problems UNLESS there is a maximum cap on pregnant animals and the bunnies were taking up slots for pregnant animals, leaving only a few slots left over for others.  That's a possibility, and if it is the case I should see evidence of it when I use larger starting populations.

So, the bunny population explosion was not sufficient explanation for this sterility phenomena.  That said, I'd planned to leave them out of my next run anyway.  Grazers are just harder to work with in this kind of trial, so I want to keep them to a minimum.

[m-logik]

I wouldn't put down the results with the peahens as conclusive just yet. It's always been the case that birds can lay an unfertilized clutch of eggs. I would collect the eggs and try again with the same one to be sure. Also, in my experience, egg layers pastured on a nest box won't produce a fertile clutch twice in a row. In my 34.11 forts I would always have to move the mother to a different nest box to get her to successfully reproduce again. So that could be what you experienced with the known fertile peahens. Although I should note I have tried any egg layer breeding in 2014 yet.

In any case, good science. I look forward to seeing more of your results.

[Solon64]

According to the wiki, n 0.34, the "animal cap" was around 50 per type of animal, so a bajillion bunnies shouldnt affect the other animals, assuming the rules are the same as in .34, which we cannot at all safely assume yet.  They also would not breed if children comprised 75% or more of the population of that type of animal, again an unsafe assumption from .34.

Unsafe or not, if the breeding rules haven't changed, then neither of these conditions explains the peahen not breeding.  More science is required, but the initial results seem to show a devastatingly high amount of sterility.  This will need to get sorted out eventually.  Perhaps something with the [ORIENTATION] tag being added that snuck into the animal code?  All of his male animals are in fact "homosexual" and won't breed with the females?

Gotta admit, I'd laugh a bit if that was the case.  Heck, at the current rate, it may even be an inverse of the current dwarven rate for homosexuality, heh.

[Tacomagic]

I wouldn't put down the results with the peahens as conclusive just yet. It's always been the case that birds can lay an unfertilized clutch of eggs. I would collect the eggs and try again with the same one to be sure. Also, in my experience, egg layers pastured on a nest box won't produce a fertile clutch twice in a row. In my 34.11 forts I would always have to move the mother to a different nest box to get her to successfully reproduce again. So that could be what you experienced with the known fertile peahens. Although I should note I have tried any egg layer breeding in 2014 yet.

In any case, good science. I look forward to seeing more of your results.

I've seen peahens do back-to-back clutches in the same nest as of 40.06 (my last fort I had 1 hen and 1 cock, and the hen produced 3 fertile clutches in one nest without being moved and locking the door right away after letting the chicks out), so I think that might be fixed, but it's always possible there was an egg collection in there.  Hard to know, those dorfs are lightning fast with egg collection.  It might be that at least one collection is required between fertile eggs as you say.  I'll have to keep my eye on that.  Maybe see about unlocking all peahen doors after chicks hatch to clean everything out before starting the next attempt.

[Tacomagic]

According to the wiki, n 0.34, the "animal cap" was around 50 per type of animal, so a bajillion bunnies shouldnt affect the other animals, assuming the rules are the same as in .34, which we cannot at all safely assume yet.  They also would not breed if children comprised 75% or more of the population of that type of animal, again an unsafe assumption from .34.

Unsafe or not, if the breeding rules haven't changed, then neither of these conditions explains the peahen not breeding.  More science is required, but the initial results seem to show a devastatingly high amount of sterility.  This will need to get sorted out eventually.  Perhaps something with the [ORIENTATION] tag being added that snuck into the animal code?  All of his male animals are in fact "homosexual" and won't breed with the females?

Gotta admit, I'd laugh a bit if that was the case.  Heck, at the current rate, it may even be an inverse of the current dwarven rate for homosexuality, heh.

Hmm, that 75% child population thing may have been what stopped my peahens from breeding.  The two clutches that hatched were each pretty big.  Around 6 chicks each.  That would have made my population over 66% child.  Good thing to know, I should make it a policy to butcher baby animals rather than cage them so they don't skew the results by causing a different kind of infertility.

Between that and the possibility of needing to have at least one infertile egg collection between clutches certainly shows that I need to take more extraordinary means with birds to prevent false positives.  Probably make it a policy to give the birds a month between letting the chicks out and locking the doors again.  And leave the doors unlocked of any bird the breeds.

I'd try it with the existing peahen to see if she'll breed, but my fort is about a month away from a nasty tantrum spiral. I don't think I've got enough time to try to get a batch of chicks out of that peahen before the place goes nova.  Better to start fresh and work better at controlling kooky variables.

[Dame de la Licorne]

Hiya,

I made the original report over on Mantis, and I wanted to mention that my non-breeding camels (which triggered the report), were all brought along as calves, so babies are NOT 100% fertile (or at least they weren't at that time, and I see no reason that it would have changed in the meantime).

-Dame de la Licorne

[MarcAFK]

It seems like an orientation tag thing.....

[Dame de la Licorne]

Hiya,

It seems like an orientation tag thing.....

Yeah, that seems reasonable and I was planning to do some testing to determine exactly how the ORIENTATION tag works for dwarves (the wiki doesn't seem complete since I'm not getting the results it says I should) and I can do the animals at the same time.  Unfortunately, I'm on vacation and won't have access to my DF computer until next week.  Depending on results from other players' tests, I may or may not end up doing some !!SCIENCE!!

-Dame de la Licorne

[therahedwig]

Hiya,

It seems like an orientation tag thing.....

Yeah, that seems reasonable and I was planning to do some testing to determine exactly how the ORIENTATION tag works for dwarves (the wiki doesn't seem complete since I'm not getting the results it says I should) and I can do the animals at the same time.  Unfortunately, I'm on vacation and won't have access to my DF computer until next week.  Depending on results from other players' tests, I may or may not end up doing some !!SCIENCE!!

-Dame de la Licorne

Actually, I've been thinking about that.
The wiki says that it should be(for male dwarves toward female dwarves) 0:0:1 if you want a breeding colony. But as far as I know, it should be more like 0:1:1, because dwarves need to have relationships before they can marry. If the wiki is correct however, then it will be 50% only lovers and 50% married. Worth a try however.

[Swonnrr]

Hiya,

It seems like an orientation tag thing.....

Yeah, that seems reasonable and I was planning to do some testing to determine exactly how the ORIENTATION tag works for dwarves (the wiki doesn't seem complete since I'm not getting the results it says I should) and I can do the animals at the same time.  Unfortunately, I'm on vacation and won't have access to my DF computer until next week.  Depending on results from other players' tests, I may or may not end up doing some !!SCIENCE!!

-Dame de la Licorne

Actually, I've been thinking about that.
The wiki says that it should be(for male dwarves toward female dwarves) 0:0:1 if you want a breeding colony. But as far as I know, it should be more like 0:1:1, because dwarves need to have relationships before they can marry. If the wiki is correct however, then it will be 50% only lovers and 50% married. Worth a try however.

Negative, there was a post of Toady (I think in the threadnaught who talked about orientation first) that explained that it was:
nothing-lovers-babies (or something like that)
The second one are the population that want a "lover" relationship, but no marriage. The third one is dwarves interested in a "lover" relationship, then marriage.

[Dame de la Licorne]

Hiya,

Negative, there was a post of Toady (I think in the threadnaught who talked about orientation first) that explained that it was:
nothing-lovers-babies (or something like that)
The second one are the population that want a "lover" relationship, but no marriage. The third one is dwarves interested in a "lover" relationship, then marriage.

Yes, that's what I read, but when I did [0:0:1] for each caste, I ended up with 0 romantic relationships, which has been confirmed by Quietust (not a problem in vanilla, is a problem with altered ORIENTATION tags), so there is probably a bug in there somewhere, but it needs to be narrowed down somehow as to where exactly the bug is.

For anyone interested, the ORIENTATION bug report on mantis can be found here: http://www.bay12games.com/dwarves/mantisbt/view.php?id=7905

-Dame de la Licorne

[Tacomagic]

Hiya,

I made the original report over on Mantis, and I wanted to mention that my non-breeding camels (which triggered the report), were all brought along as calves, so babies are NOT 100% fertile (or at least they weren't at that time, and I see no reason that it would have changed in the meantime).

-Dame de la Licorne

Bummer. I guess I just got lucky on the bunnysplosion.  I'll cross that off my list of things to test.

Hiya,

Negative, there was a post of Toady (I think in the threadnaught who talked about orientation first) that explained that it was:
nothing-lovers-babies (or something like that)
The second one are the population that want a "lover" relationship, but no marriage. The third one is dwarves interested in a "lover" relationship, then marriage.

Yes, that's what I read, but when I did [0:0:1] for each caste, I ended up with 0 romantic relationships, which has been confirmed by Quietust (not a problem in vanilla, is a problem with altered ORIENTATION tags), so there is probably a bug in there somewhere, but it needs to be narrowed down somehow as to where exactly the bug is.

For anyone interested, the ORIENTATION bug report on mantis can be found here: http://www.bay12games.com/dwarves/mantisbt/view.php?id=7905

-Dame de la Licorne

This is interesting because in the breeding populations I was seeing 20-25% sterility.  That actually lines up suspiciously well with the default orientation settings of [75:20:5] for homosexual relationships.  So it could very well be that all creatures are being given the default oreintation values.  At least all civilization creatures (Which embark animals might internally flag as).

If we are getting a 25% homosexual domestic animal population, we should see that pretty conclusively by breeding a large number of isolated female dogs with a sufficient number of male dogs.

[silverskull39]

Interesting science going on here. PTW