Star or white stripe on face

[Dane layer]

I was wondering why most horses have that star on thier forheads or a white stripe down their faces? I know not all do but most.  I know they vary in size but just curious as too why they have them.

[caikgoch]

Google after "whorl & horse"  or "hair whorl".    There are a lot of theories but not much fact.     The color is genetic and the same as color patterns common on specific dog breeds.

[Hiway]

[heavyhorse]

Interestingly, when there are clone horses (and there have been a few),  they are genetically identical (of course) but the white markings on legs and face vary.  A lot.  Leading to the conclusion that white is a result of uterine influences rather than genetics.  




Which brings us back to:

On 8/12/2017 at 7:09 PM, caikgoch said:




There are a lot of theories but not much fact.

Although the base color is absolutely genetic, and predictable to the extent that some breed registries will challenge you if you report offspring that don't conform to genetic color rules.

[Ramseys]

Lots of color patterns are caused by the position of the fetal animal in the placental sack.




That's why even identical twins have some slight variation in markings.




  

[Saturnine]

On 8/12/2017 at 7:29 PM, Hiway said:




<a class="ipsAttachLink ipsAttachLink_image" href="https://zoowg.org/uploads/monthly_2017_08/You_c5371d_1446999.jpg.cf.jpg.000b93d14854c702fd08ddfa5c3e4ae9.jpg.211a25b558f4aa10226a309b063e63b8.jpg" data-fileid="2078"></a>

I wonder if that's photoshopped?

[heavyhorse]

Nah.  Completely random.  The foal was in a provocative position in the womb--