It is well supported that the aurochs had curly, frizzy forelocks on its forehead. It is reported from Anton Schneeberger who wrote: “The forehead, because of the curly, frizzy hair, makes them terrible to behold”. The posthumously (1634) published report by a certain Swiecicki mentions this feature as well. Also, belts were made from a bull aurochs’ forelocks in historic times. They were said to increase the fertility of women or help women having difficulties giving birth (see van Vuure, 2005). As a brutal fact, those forelocks were peeled together with the facial skin from the skull of the captured aurochs when it was still alive. Not to forget, Charles Hamilton Smith’s famouspainting of a bull aurochs from 1836, which is drawn from an oil painting dating back to the 16th century, shows these curly forelocks very clear.
Such forelocks are very widespread among domestic cattle. I think their function might be display, apart from their probable protective function for the skin between the horns during combats. Bovids that live in hot regions tend to have fleshy structures for display, mostly dewlaps. Those in cold, northern regions cannot effort the heat lost caused by such appendages and therefore often have hairy display structures; such as the mane of the Barbary sheep or the beards of musk ox and bison. The European aurochs is climatically and geographically in between and funnily so are those structures. Those forelocks give the bulls indeed a fierce look, what could be useful in scaring off rivals – the mealy mouth, which is widespread among Bovidae, might have the same function. While the intensity of the forelocks of taurine cattle varies from breed to breed (Chianina, for example, doesn’t have any at all), zebuine cattle never have such (at least not that I know of). This brought me the idea that it might be a legacy of hybridization with bison. When I then got to know that such hybridizations did take place (see Verkaar et al.) I felt that this thought might have some plausibility in it. Although only introgression from Bos to Bison and not reverse is proven so far, I think it is likely that there was mutual hybridization because only sex-based markers (Y and mt) were used in this study.
Interesting side fact: The forelocks, or actually massive bulk of hair, in Bison is not only used for display and as a bumper during combat, but also to remove snow from the ground in order to reach the grass beneath it. Horses do that with their hooves, while cattle, and probably also aurochs, have no such abilities.
Forelocks in cattle are present in both sexes, but many domestic bulls that have forelocks also have a kind of “mane”. Actually it is not a mane as a lion or a Barbary sheep has, but it is merely the same kind of locks that is present all over the neck, parts of the shoulders and often also the entire face. You find that in a lot of breeds. Some Lidia have it to a very prominent extent (here), and also Chillingham cattle have it. But what is most interesting to me is that a number of Heck bulls in Oostvaardersplassen exhibit such a “mane” (f.e. here), while virtually no Heck bull outside the reserve does. Richard Marsh, the cattle warden of Chillingham, believes that this mane serves to protect the skin on face, neck and shoulders of the bulls. So if Lidia and Chillingham cattle, both breeds in which combats often (in the case of the latter always) decide on reproductive success, show that trait, and if Heck cattle in OVP suddenly developed it, it might indeed have such a function. I know that this is based on a weak ground: man plays a way more important rule in reproductive success of Lidia bulls than combat does, many cattle which are totally man-selected do have that trait too, it might have become coincidentally fixed in Chillingham cattle due to all the bottlenecks, and the “mane” is not all that common among OVP bulls. But, on the other hand, the presence of the forelocks themselves in non-primitive breeds is not a prove against their presence in the aurochs either, and the OVP population has been exposed to natural selection for only 10 generations yet. Anyway, it is just a thought.
|The "mane" of a Chillingham bull|
While the curly hair on face, neck and shoulders always has the same colour as the rest of the body, the colour of the forelocks varies in wild type-coloured bulls. The forelocks of cows are almost always of a lighter colour than the rest of the head, with a dark shade “coming from above”. In bulls however, the forelocks can be of an either black, reddish brown, orange or blond colour (in de-phaeomelanised cattle like Podolian cattle, the colour turns grey of course). There is no definite clue on what the colour of the aurochs’ forelocks exactly was. Black is the best-supported colour for the simple fact that forelocks of a colour different from the rest of the head are never mentioned or depicted anywhere – neither by any historic reports nor cave paintings or Smith’s aurochs. If the forelocks had been of a special colour, Schneeberger would have probably mentioned it since he also mentioned the muzzle ring and the eel stripe which contrast with the black base colour. There is also a Libyan petroglyph showing a North African bull aurochs, in which both a muzzle ring and a light colour saddle are indicated, but no bright forelocks. Gaurs, on the other hand, have bright blond hair between the horns and so do zebus. So I assumed bright forelocks were a basal state and dark ones the derived state of northern Aurochs. However, Tom Hammond pointed out to me that bright forelocks could be the result of reduced sexual dichromatism which is the case in Gaur and most of the aurochs-like breeds. And indeed the first breed with a clear sexual dichromatism that comes to my mind has mostly dark forelocks in bulls: Maronesa. But this breed displays all possible colours of forelocks in bulls. Bright forelocks in cows are confirmed through a painting at Lascaux.
Therefore, my opinion on the colour of the forelocks in aurochs is that cows’ always were of a blond, orange or reddish colour while that of the bulls were most likely black in most cases, but perhaps there was geographic variation that allowed the presence of brighter forelocks as well. Although we have no evidence for that, I certainly would not make bright forelocks in bulls a negative selection criterion in effigy breeding.
A number of breeds, especially many Heck cattle, do have elongate hair between their horns but they are not curled. Instead they look like the fringes of a carpet. This is probably not what aurochs forelocks should look like.
Cis van Vuure: Retracing the Aurochs - History, Morphology and Ecology of an extinct wild Ox. Pensoft, Sofia 2005
Verkaar, Nijman, Beeke, Hanekamp, Lenstra: Maternal and Paternal Lineages in Cross-breeding bovine species. Has Wisent a Hybrid Origin?. 2004.