Horses and Nipples

I just wondered why evolution gives some mammals nipples and some others not. So would this mean in embryo terms that the sex of the horse occurs later in the development of the embryo or earlier ?
 
Bizzarely male horses and male mice are the few (if possibly only) male manmmals who do not have any mammary tissue. Almost all male mammals - even monotremes - do.

The sex of the embryo is determined at fertilization becuase either there is an XY or an XX. Although some specieis, including human, develop as female until a set zygotic stage it doesn't mean that the embryo is anything but the male or female it was at fertilisation. Setting aside of course chromosomal abnormalities and without any reference to or comment upon human sexuality which is an entirely different point!
 
Bizzarely male horses and male mice are the few (if possibly only) male manmmals who do not have any mammary tissue. Almost all male mammals - even monotremes - do.

The sex of the embryo is determined at fertilization becuase either there is an XY or an XX. Although some specieis, including human, develop as female until a set zygotic stage it doesn't mean that the embryo is anything but the male or female it was at fertilisation. Setting aside of course chromosomal abnormalities and without any reference to or comment upon human sexuality which is an entirely different point!

Thank you Shay for the explanation.
 
A wonderful question.

I was out riding a few months ago, with a bloke my age and a little less experienced, with a woman who had trained as a vet and is now a world-class endurance rider as well as running a stud farm and riding centre.

The conversation waddled through the subject of horses who insist on stopping and standing still to pee, rather than waiting for an appropriate moment, and the other bloke asked if a gelding or a stallion of a certain age might develop prostatitis and have trouble peeing.

There are no stupid questions. Everything is interesting.
 
Male horses do have rudimentary nipples on the underside of the sheath.. They're not very easy to see on many horses but much easier on donkeys.
My little cob has very obvious ones but not the large cob.... I may have been sold a donkey, though he has got very tiny ears!
I see this is a very old post but thought I'd give it a try! We have a colt that was born few days ago and he has what looks like nipples!! He is 25% Welsh Cob... could the "cob" in him be why he has nipples on his lil tiny sheath?? So confused.
 
Male horses do have rudimentary nipples on the underside of the sheath.. They're not very easy to see on many horses but much easier on donkeys.
My little cob has very obvious ones but not the large cob.... I may have been sold a donkey, though he has got very tiny ears!
Now this post has came back up am sure I have noticed small nipples (udders) on a few geldings and a stallion before defo on my old gelding that was cut late edit to add on the sheath not like nicnacs pic more like 2 wee spots when av noticed it
 
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Now this post has came back up am sure I have noticed small nipples (udders) on a few geldings and a stallion before defo on my old gelding that was cut late edit to add on the shefe (sp) not like nicnacs pic
I've had horses my entire life and I've never seen a gelding or stallion with them. Seriously thought something was wrong with this colt. We thought it was a filly at first 🤣 Thanks for your reply.
 
Will check both my geldings tonight for nipple presence on sheaths - can't say I've ever noticed them so guess aren't monotremes (whatever a monotreme is) Gosh yes male donkeys do have nipples!


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It looks like something David Attenborough has discovered...some sort of deep sea creature. Well...if you forget the furry bits
 
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