Koniks with a standing mane in Oostvaardersplassen

Some Konik ponies have a standing mane. This is likely the result of Przewalski's horse introgression, as the crossing-in of this wild equine is documented in the Konik pedigree [1]. I have seen such specimen especially often on photos from Polish breeding sites, such as Popielno, which is one of the most important Konik breeding sites in Poland. There are also very Konik-like ponies in Germany that can have an upright mane, but those are likely to be Heck horses (both breeds are used indiscriminately in grazing projects, there is no breeding book so they are virtually indistinguishable in Germany). But the ponies at Oostvaardersplassen are "pure" Koniks in any case, mostly purchased from Popielno. I have not seen any OVP ponies with a standing mane until I found a relatively recent video on youtube, go here. Sometimes a domestic horse can have a standing mane when it is not fully grown yet (all foals have a standing mane), and sometimes it looks as if the horse has a standing mane when viewed from the side when the bulk of the longer hair of the mane falls to the other side and the shorter hair at the edges of the mane are standing, but I think in this case it is rather clear that those are truly fully grown Koniks with a standing mane, see shots like 1:27. It is interesting to see that also in OVP, the largest Konik breeding site in western Europe, there are individuals with a standing mane. Particularly interesting is the question if the frequency of individuals with a standing mane would increase over time if it provides a fitness advantage, as there is no artificial selection on those ponies. 

[1] Jaworski 1997: Genealogical tables of the Polish primitive horse. Polish Academy of Sciences.