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As the title says, you know stuff like minotaur, lycanth or werewolf, cat or dog folk, etc especially for the female specimens.

I want to know what happen if quadrupedal mammals which usually have their teats around their stomach evolve normally to become bipedal, will their teats change place to around their chest or still develop around their stomach?

And I heard carrying baby is the reason primate breast developed around chest (correct me if I'm wrong) so just consider in both situation if this quadruped mammals carrying their baby (or whatever real reason that make primate developed their teats there) and if they don't, what the musculature especially their breast or anatomy would look like in both situation, considering most of them have multiple breast or nipple.

Reason why I ask this? It can help me see how their muscle look especially for female and help me to imagine what attire and armor can be look like for them.

Also just in case I consider human chimera type like centaur, harpy and other mythological or fantasy creature that basically human body (especially that have human breast already) strap with animal part is not part of this question. It mostly for pure mammalian animal maybe exception if they only have human face and the rest still animal, like sphinx for example, with other matching criteria I describe, if there such a creature.

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Li Jun
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    There are several species that have them in alternate locations: elephants are quadrapeds and have mammaries in the human place, and cetaceans have them more in their "armpit" region. – Borgh May 06 '19 at 14:45
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    @Borgh With elephants I've read that it's because the vaginal opening is further forward than usual, due to the adults' great size (it reduces the height the baby has to drop). I dunno about cetaceans, though; I thought the nipples were in the genital region? Like it says here: https://jackiehildering.files.wordpress.com/2019/01/fb-memes.001-1.jpeg?w=658&h=494 – SealBoi May 06 '19 at 15:14
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    Bears also have teats on their chest,as do bats(though theirs are on the side, not front) :D – Haan May 06 '19 at 15:57
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    It never before occurred to me to wonder about werewolves' nipples. Do they just have two in wolf-form? – RedSonja May 07 '19 at 07:37

4 Answers4

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Mammals (males as well as females) have what are called "mammary lines":

enter image description here

This is a bilateral structure that rules where mammary tissue can develop. Apes (among whom humans) generally have two and those towards the cephalic end of the line. Some people have three or four. Many quadrupeds have breast tissue at the caudal end of the lines --- a cow's udder being the best known.

Not all quadrupeds are built alike.

Dogs, wolves, cats, pigs and so forth have many operational breasts --- eight or ten, and all up and down the thorax and abdomen:

enter image description here

Note that bears have four breasts and are already in the "human positions":

enter image description here

Same goes for elephants, who have two:

enter image description here

My answer would be:

UNLIKELY

Carrying babies around is not likely to be the cause of breast migration. Newborns already have the ability, if left to their own devices, to crawl and find mama's breasts. Most primate babies are pretty good at gripping and hanging on to mama as she moves around. Evolution isn't reactionary. The animals that evolution happens to react to the vagaries of its change.

Edit: (With Elemtilas' permission via JBH). IMil points out that if we all came from one source animal, then nipples most certainly migrated as today they are on different locations for different mammals and have different counts. However, from an ultra-simplistic point of view, all mammals basically began as quadrapeds where babies sat on the ground to reach over to, or up to, the teats. Yes, bipeds must lift the child to make up the difference (or lie down). But since they're capable of doing so, and perfectly willing to do so, there's not been evolutionary pressure for the nipple to move for bipeds.

However, if 100 million years from now they were to migrate, they'd probably migrate to our ankles or hips as those would be far more convenient than the stomach, which would get in the way of playing video games.

Since your basic question boils down to a fantasy race, I'd suggest that it's your world, you make up the rules. But do consider the following:

  • Breast tissue in dog / wolf / cat / elephant / cow folk will not "migrate" upon them taking a bipedal stance. Their breasts will continue to be in their ancestral locations most likely.
  • "Breasts" in the human sense of the word probably will not evolve in these kinds of races. Wolffolk with two D-cup human-like breasts exist solely to attract and titillate the desires of human males. While I'm not complaining, the arrangement makes them more "relatable", like this example of a typical wifewolf vs this possibly more likely but less human-relatable example.
  • Clothing: why would beastfolk need clothing at all? Clothing has nothing to do with species or race; it is a social construct (for the most part) and I would suggest considering it as such for your own beastfolk. If your werewolves are furry, they won't need clothing at all, because they can already pant to reduce body temperature and they've already got fur to keep warm. If they are not furry, they may only need clothing in the depths of winter.
  • Armour: here you'll need to consider their body shape. If your werewolves are more canine in shape, then you'll want to consider armor to conform to a canine body shape. If they are basically human body shaped but with beasty features, then you'll be looking at armour fitted to a human body plan. If your females retain canine breast morphology (eight all along the chest and abdomen; flat except when lactating) then male and female armour will be essentially identical. If you choose to go the human male lust enhancing route, then you'll need armour fit for a Wagnerian Valkyrie.
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elemtilas
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    You're making an assumption that a biped would not need clothing because of fur: being a biped exposes more of the body to wind, which can have a significant effect on the ability to maintain body heat. And, in anything but a tropical environment, clothing isn't a mere "social construct" but absolutely essential to survival. – Keith Morrison May 06 '19 at 16:13
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    @KeithMorrison -- Actually, my underlying assumption is that clothing is primarily cultural. I disagree that it is absolutely essential to survival, as evidenced by the Yahgans. If people can thrive naked in Tierra del Fuego, they can thrive naked in Italy or Morocco or just about anywhere else. Are some articles of clothing necessary for survival? Perhaps so! And I don't discount clothing's use as protection. It's the fact that móst humans wear clothing all the time, even when we don't need to and even in our climate controlled environment that leads to the assumption. (cont...) – elemtilas May 06 '19 at 16:21
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    ... Further, my assumption is that non-human people probably will not have the same cultural and physiological needs that we have. Thus, clothing may well be a non-starter for wolffolk, even if they are exposed to a bit of breeze while standing. Might such a person wear a cloak while travelling? Maybe! Will such a person wear that cloak all the time?, even while inside a house or a vehicle or a temple or a theatre? Quite possibly not! – elemtilas May 06 '19 at 16:23
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    This is a good answer. Let me add to it: there's no evidence that I know of in all of Terran history that mammary glands have migrated anywhere. From an ultra-simplistic point of view, all mammals began as quadrapeds where babies sat on the ground to reach over to or up to the teats. Bipeds must lift the child to make up the difference (or lie down). If 100M years from now they were to migrate, they'd migrate to our ankles. After all, we don't all keep our genitals in the same place, why not nipples? – JBH May 06 '19 at 16:45
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    "why would beastfolk need clothing at all?" How about for practical reasons? "minotaur, lycanth or werewolf, cat or dog folk, etc" tend to be depicted as not just bipedal versions of their quadruped cousins, but also as highly intelligent beings. In that situation, being able to carry things other than in your mouth, or at most in your hands, is really handy (no pun intended)! – user May 06 '19 at 16:54
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    clothing is insulation you don't have to "pay" for biologically speaking if the creatures live in colder climates clothing is a sizable advantage. Also panting is actually a poor cooling system. – John May 06 '19 at 17:35
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    @aCVn, two words: "tool belt". "Clothing" as a way of carrying things around is likely to take the form of backpacks, belt pouches, and harnesses, rather than things the typical person would think of as clothing. – Mark May 06 '19 at 20:47
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    @aCVn --- I guess my point here is that, at least to my way of thinking, "you" all are looking at clothing from an entirely human, Western culture perspective. Practical reasons? Unless you're doing some task where protection is required (chemist, blacksmith, sous chef) most humans just don't actually need to wear clothing. We wear clothing all the time because our culture instructs us to. As for depictions of beastfolk, most of those are drawn & imagined in such a way that they are little more than "kingdom of hat" people. They are basically humans with a couple animal-like (cont...) – elemtilas May 06 '19 at 23:03
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    ...features. I'm looking at this from the perspective of the beastfolk themselves. How might they be and behave differently from modern Western humans. So my assumptions are that they most likely will not be human and will not behave as humans behave and their cultures will not be very be human-like. – elemtilas May 06 '19 at 23:04
  • @JBH --- Please edit my answer if you don't mind! – elemtilas May 06 '19 at 23:05
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    @Mark --- Tool belts are an excellent case of "clothing" that is / would be "practical" for fully clothed humans and naked wolffolk alike! (Mind you, a leather tool belt isn't really what I'd call "clothing"!) – elemtilas May 06 '19 at 23:07
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    @JBH Walking on all fours does not automatically make something a quadruped. When the primary mode of locomotion is to use four legs, then the species if a quadruped. – forest May 07 '19 at 02:20
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    @forest Is there a question? or are you simply trolling? How does your observation materially affect my comment or my edit? – JBH May 07 '19 at 02:29
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    @JBH "that there's no evidence that I know of in all of Terran history that mammary glands have migrated anywhere." - the fact that different mammals have nipples in different places is the evidence that they have migrated. All mammals share a common ancestor, so if we humans have two nipples and dogs have six, this means the number and position have changed quite a few times. Or do you mean something radical, like to the hands? – IMil May 07 '19 at 04:17
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    @IMil, you bring up a good point. I'll make the correction and reference your comment. Thanks! – JBH May 07 '19 at 04:20
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    @IMil (and JBH) --- They haven't "migrated". As I pointed out in the answer, there are bilateral lines along each side of the body where mammary tissue can appear. Just because some animals have two (or four or six or eight) in a particular location doesn't means they "moved" or "migrated". All that means is their ancestors had tits in those places. The most primitive primate seems to be the lemur, and they've got as many as six. I think the evolutionary factors that give humans & elephants 2, dogs 8 and lemurs 6 is so far back in time as to be irrelevant to the question at hand. – elemtilas May 07 '19 at 05:08
  • i agree with you about clothing but i also agree with the other commenter too, after all clothing also have some functionality or just for show or attrativeness or fashion hence why i need to know how the body look to at least give them convenience to wear for certain animal, when i see the mammary lines picture you show the first thing in my mind was cloth or pouch design to carry their children though. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRAZh1nzYWQSpcv9PQKyhn63228HwLfIPW61Hra14JoyPFLCTqp – Li Jun May 07 '19 at 07:31
  • oh yeah mind to elaborate what you mean with canine in shape ? i think its clear enough that the creature in my question is not just human body with animal head or viceversa if that what you mean with "human body shaped but with beasty features" oh yeah also the armor at least wont goes fanservice route ofcourse otherwise its not protective gear so for armor im more focus on the practicality although there some ornamental at best. – Li Jun May 07 '19 at 07:44
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    @elemtilas the question is about hypothetical evolution of a typically quadruped animal into a bipedal one. The necessary changes in skeleton, muscles, etc, are quite extensive and can take millions of years of natural selection. One or two pairs of nipples could easily disappear in the same amount of time, and if the upright pose gives advantage to higher nipple location (e.g. easier to hold the child), changing nipple position would be pretty trivial compared to all the other changes. – IMil May 07 '19 at 09:08
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    As @elemtilas points out, the nipples don't migrate as they can occur anywhere on the milk line. Indeed not all humans have them at exactly the same height (measured by proportion of the distance from the pubis to the shoulder, for example) nor does anyone with exactly two have them at exactly the same height. What could in principle change, and what I think the question is really about, is "Could the average position change over time?" – David Robinson May 07 '19 at 13:35
  • "Newborns already have the ability, if left to their own devices, to crawl and find mama's breasts" not necessarily new-borns, not necessarily mammas, nor even always on the same damn species,, my cat has a predilection for nuzzling & kneading with his paws around where mine are when he wants feeding, he's a very confused little kitty, cos I'm not a cat, & male. – Pelinore Apr 10 '21 at 00:06
  • @Pelinore -- That's actually fairly normal cat behaviour. If you don't mind -- cool! If you do, there are strategies you can employ to ween your boy of that habit. – elemtilas Apr 10 '21 at 00:19
  • @elemtilas That habit is one I can live with, what I'd far rather is a method of wiping his memory so he doesn't just poke his head around it & look at me in that slightly bored way when I try to play the curtain game (poking it from the other side when he's on the windowsill) with him these days, as a kitten he'd attack not knowing what was poking, far more satisfying:)) – Pelinore Apr 10 '21 at 00:30
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Sure, it's called convergent evolution.

analogous traits arise when different species live in similar ways and/or a similar environment, and so face the same environmental factors

Natural selection expressed through (first) survival, and then reproductive success, ensures the continuation in the species of those traits which enable the organism to reproduce. If it became an advantageous survival trait, then yes, the breasts could migrate (so, for example they could run without udders being ruptured by collision with their knees. - But that's an oversimplification - in practice the upright walking and the breast migration would occur in a not-independent way, over considerable time.

That being said, there's an alternative: Atavism, a phylogenic trait - ie. one which has occurred in the past-history of the organism's ancestry, but the environment has resulted in the gene being switched-off - is of necessity switched-on again. You need to ask yourself "what is deep in this organism's past that can be switched-on again? That could result in the breast's being developed here (ie. wherever your story demands).

This all being said - it's all up-to-you as the writer to make a decision as to how much to give explanations. Sometimes the idea that the reader comes up with their own explanation is useful. See: Death of the Author. (That is also an oversimplification).

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Now that you mention it, there might be an issue with that.

If they were of any decent height relative to the babies, then they'd have to carry them to suckle. With mammaries in the abdomen like most mammals, the mothers would have to be cradling the babies right against their lady parts, which is hardly a good idea - mainly, either could get an infection of some sort. Also, what if they were menstruating? Additionally, it's much easier to carry things against your chest than at your hips.

Perhaps you're right and it would be beneficial for the mammaries to migrate upwards.

SealBoi
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    But why should the have to carry their young? Most mammals do not breastfeed "on the run" - they do it in a safe location at their leisure. Even if humans have breasts on the chest to facilitate breastfeeding when carrying infants, you also need to have a reason for them to be on the move without resting periods. This is reasonable for the human hunter+gatherer style (with women spending long periods of time walking to get food), but not an exclusive hunter style (where carrying an infant would be a disadvantage, especially if there's a social structure that can care for infants). – Luaan May 07 '19 at 10:16
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    Most likely, the breastfeeding style developed in our arboreal ancestors, and has nothing to do with bipedal walking. It's more about the lifestyle of the animals in question and how long it takes for the infants to become (largely) independently mobile, how large they are at birth, how often they need to feed, how the adults procure food... – Luaan May 07 '19 at 10:18
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    @Luaan most animals don't have young born as underdeveloped as large brains force humans too either. For hunters being on the move is even more important, a carnivore tribe will have to be nomadic to not deplete local wildlife. – John May 07 '19 at 14:11
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I think SealBoi hit the right note, in that the question you should be asking is "how do my critters nurse their young?". If they always lay down to let their babies suckle, there is no reason for "migration" or other changes to occur. If they need to suckle while standing on two legs, that is a good reason to transition to a more human-like anatomy.

The reason I'm posting an answer instead of a comment is to address one of your other questions; what would these critters' attire look like? While answering your question as stated is relevant, something else to keep in mind is that most non-lactating mammals are flat-chested. Human mammaries, which are always prominent, are the exception rather than the rule¹. (One of my favorite examples is from "Uhurah's Song", wherein one of the felinod aliens asks a human female what happened to her young, having mistakenly assumed said human to be lactating.) As such, unless you adopt this trait also², your female attire is likely to be divided into "normal", and one or more varieties to accommodate gravidity and/or lactation. (On which note, do keep in mind that humans have special "maternity" clothing.)

(¹ ...and before you mention cows, make sure to find a picture of a non-dairy cow. Dairy cows are always lactating, not to mention the effects of selective breeding for milk production.)

(² ...which would be strictly for fanservice. Literally. To wit, I remember reading a claim somewhere that the only reason human females always have pronounced mammaries is because of their "effect" on human males, specifically, as an incentive for "dad" to stick around. By corollary, if your critters' females are typically single moms, there would be no reason for this trait to develop.)

Matthew
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  • hmm..the creature in my question is more diverse though basically what if all the mammals become bipedal as i also mention several iconic fantasy creature that match stuff like this for example minotaur, werewolf, cat and dog folk. and i dont think theres need some restriction that the creature must be carry around or standing to breastfeed either as my question is more generalize to what happen if they maintain their teats location like their anchestor or follow human like teats but still maintain the number, after all several answer show some quadruped have similar location like human cont – Li Jun May 07 '19 at 06:55
  • and elemtilas answer so far is the most helpful to me to know animal teats anatomy better although there some assumption or misunderstanding, and yes at first i was more concern about female minotaur base on my false assumption of dairy cow although there also exist dairy minotaur and other bipedal pasture animal by human which doesnt necesarry to have clothing or armor still would help my curiousity. cont – Li Jun May 07 '19 at 07:15
  • also i think for several creature that have teats locate around their thigh or crotch area to maintaining in that location while still bipedal still can help them if they maintain their nomadic life and need to keep moving from predator while their baby also maintain some trait of their anchestor like can stand after birth (correct me if that cannot happen). – Li Jun May 07 '19 at 07:17
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    The reason for human breasts being the way they are is mostly unknown. It's unlikely it would happen to be interesting to human males without a reason, though - you're arguing backwards. It would only keep the males interested after males became interested in what's usually a sign that you cannot reproduce with this female (i.e. the exact opposite of what evolution would naively "select" for). There's a few theories for the origin of this behavior, but just saying "because males like boobies" begs the question. – Luaan May 07 '19 at 10:23
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    @LiJun Breasts have a cost. They take materials and energy to develop, they are vulnerable, prone to genetic deterioration and infection (both promoting cancer development), etc. In the end, the number of breasts and the typical number of potential offspring (being nursed simultaneously) is roughly balanced. The two also typically have a lot to do with the size of the offspring compared to the adult female, the gestation (and breastfeeding) period etc. etc. It'd probably be impractical to keep the teats in the same place in a bipedal, but you have other choices than the chest :) – Luaan May 07 '19 at 10:35
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    Being able to stand bipedally after birth might be a bit of a stretch. OTOH, that brings up an interesting possibility; if your critters are only "partly bipedal" (shorter legs relative to humans, somewhat able to get around on all fours still), then babies that can stand (on all fours) right away — note; these are almost always "prey" species — might have no problem nursing from groin-level mammaries. In fact, that could be an argument against mammary migration. Really, I think the upshot might be to decide what you want, and then justify it. – Matthew May 07 '19 at 16:29
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    Luann, I have to disagree. First, because you can mate with a female that's given birth. Second, because the fact that she's nursing says "this female is fertile". I don't see how the hypothesis I mentioned (not mine, BTW) is necessarily "arguing backwards". You're also ignoring the key part of the hypothesis; "manservice" was the mechanism. The function/benefit is that dad sticks around to help raise the child. – Matthew May 07 '19 at 16:35