Most of the
external and morphological traits of the aurochs are well known to us thanks to
numerous superb skeletal remains and also contemporaneous artworks and written
sources. While the skeletal material is complete, well-preserved and numerous
enough to give us a very precise picture of the aurochs’ morphology, its
dimorphism in sex and also, to a certain degree, variation along time and
region, artistic impressions and written accounts are sometimes not comprehensive
or unambiguous enough to clear all open questions. Do not get me wrong, the
picture of the aurochs we have is very precise. But there are some aspects that
are questionable and still leave some room for speculation. In this post I give
you overview over all those points that come to my mind.
The length
of the dewlap
It is
unquestionable that the aurochs had a dewlap of a certain size. Tropical bovines
tend to have a large one (banteng, gaur, kouprey), more northern ones not so
much (bison). Zebuine cattle have a large dewlap as well, probably both due to
domestication and climate. The European aurochs, on the other hand, probably
could not effort too much heat loss caused by a large dewlap, and historic
references probably would have mentioned it if it was an obvious trait. But
they do not, and all artistic depictions, including cave paintings, show short
dewlaps. Most likely the dewlap of European aurochs was about as short as in
cold-adapted taurine cattle (yakut cattle, Highland cattle, Heck cattle at the
Oostvaardersplassen). It is possible that it was even shorter, but we cannot
know because of the absence of soft tissue aurochs mummies (there was,
actually, a complete skin of an aurochs found in Germany at the beginning of
the 20th century, but its soft tissue has not been preserved
[Frisch, 2010]; there might be more cases like that).
Winter fur
length
The aurochs
most certainly had a bi-layered winter fur. The undercoat was likely short and
dense, but the question is how long the outer coat was. Surely the length and
density of the winter coat was dictated by the requirements given by the
climate, so it was dependent on region. I have been wondering about the winter
fur of central and northern European aurochs. Since there are no preserved
aurochs skins, we can only guess how long the winter fur of these kind of
aurochs actually was – what was the minimum, what was the maximum of what is
physiologically useful and what was the actual case?
Schneeberger
states that the aurochs was covered in longer fur than domestic cattle, but
does not clarify whether this was generally the case or during a specific
season, and what kind of domestic cattle he was thinking of is unclear either
(hardy landraces do have a more efficient insulating coat than more derived
cattle). Looking at hardy taurine landraces that are adapted to living outside
all year round in temperate climate could provide an useful aurochs analogue. HungarianGrey cattle and Heck cattle sometimes grow a comparably long (but still not as
overlong as in Highland cattle) woolly winter fur that gives them a shaggy
appearance. In my subjective, google-based perception this is particularly
apparent in some individuals from the Oostvaardersplassen, but I might be
wrong. Many Grey and Heck cattle however have a winter fur that is a little
shorter and similar to that of Betizu and Yakutian cattle, two breeds which are
good models as well – the former having a feral history, the latter being
well-adapted to harsh cold. However, Chianina have a comparably short winter
coat yet they still do just as well in central European winters as do Heck
cattle and Sayaguesa living in the same area. So was the aurochs’ winter coat
minimalistic and as long as in Chianina, was it long and woolly as in some Heck
and Grey cattle individuals or somewhere in between like in the majority of
Heck cattle, Betizu, Yakutian cattle and other landraces? Size could be a
factor: a large animal has, in relation to its size, lesser heat loss than a
smaller one of the same morphology. Therefore a 180cm tall aurochs bull might
not need a winter fur as long and shaggy as a 140cm tall Oostvaardersplassen
Heck bull (I am not saying that this is the reason why Chianina have a
comparably short winter coat, I consider that a coincidence that is the result
of how Chianina have been husbanded as a breed). But it is questionable how
influential that factor really is here, especially because domestic cattle and
aurochs even at that height difference might still have a similar mass due to their
different morphology. Another factor is the ability to store fat, which
contributes to insulation as well and therefore influences the need for an
insulating coat.
While it
would be nice to know how long and shaggy the winter coat of central- and northern
European aurochs was exactly, I think it is not something that breeding
projects have to worry about in particular, as long as the animals do well
during winter and seem to be fit for survival under natural circumstances.
The colour
of the dorsal stripe
The
immediate answer you get is “light-coloured”. But extant wildtype coloured
cattle actually display dorsal stripes of various colour shades, ranging from yellowish-white
over yellowish-red, golden, shiny red to brown. The English translation of Schneeberger’s
report in Gesner 1602 says the dorsal stripe was of a lighter colour as
translated in van Vuure 2005, originally it says “subnigra” in Latin. This is a
bit imprecise but must have meant some kind of grey. Sigismund von Herberstein
was in possession of an aurochs skin, and termed colour of the dorsal stripe “grahlat”,
what is to be translated with grey. More precisely, this grey colour was the
result of white hairs mixing with the black hairs that covered the rest of the
body. The only cattle having a grey eel stripe without any shades of red or
yellow are those that display a diluted coat colour, such as Podolian cattle. Contemporaneous
artworks give no useful clue on the colour of the dorsal stripe; some of
paintings at Lauscaux and Chauvet cave implicate that it was there, but do not
point to a specific colour.
This opens
the following questions: did all wild aurochs have a dorsal stripe of the same
colour or colour variation spectrum, and was it as wide as in wildtype coloured
domestic cattle? Or were wild aurochs, at least the central-northern European
ones, different in having a greyish eel stripe without having diluted colour
shades at the same time? It might also be the case that, assuming the colour of
Herberstein’s skin was not artificial (due to damaging or discolouring), the
dorsal stripe in that individual was simply reduced, perhaps due to aging. I
have been playing with the thought that not all wild aurochs always had a
visible dorsal stripe for quite some time, in the same way the extent of the muzzle
ring in gaurs and banteng is variable. But the question is, was Herberstein’s
individual an exception, or representative for the rule? And if the latter was
the case, was this true for all wild aurochs or just the central-northern European
group?
Because of
these uncertainties, I don’t stick to a certain colour shade for the eel
stripe, because evidence is simply not compelling enough neither as the rule
for central-northern European aurochs nor all wild aurochs. Intuitively I think
that the aurochs, at least the African, Near Eastern, Asian and probably also
the southern European populations, might well have displayed the diversity of
colour shades for the eel stripe that domestic cattle with an un-diluted,
wildtype colour do. If I had to pick only one colour for the dorsal stripe of a
central-northern European male aurochs, I would take a very pale, greyish one
because of the literature references – but other colours might do it just as
well.
Width of
the dorsal stripe
The dorsal
stripe is usually described as “narrow”. To be exact, Schneeberger stated it
was “about two fingers wide”, therefore a few centimetres. Von Herberstein, who
owned an aurochs hide, made no mention of the width of the stripe. The “two
fingers wide” condition is most common among wildtype coloured domestic cattle.
However, in some cases, the eel stripe is rather broad, such as in some Lidia,
Maronesa or Heck bulls. In these individuals the anterior end of the stripe is
V-shaped, meaning it starts rather broad at the shoulder area (this area is
usually where the dorsal stripe is widest, it is narrowest in the lumbar region
or at its posterior end). The opposite is the case as well. There are bulls
which have a rather narrow, reduced eel stripe, for example some Sayaguesa or,
again, Lidia bulls.
Due to the
scarcity of data, we do not know whether there was variation in the width of
the dorsal stripe or not, and if that variation was as big as in domestic
cattle or less.
The colour
of the forelocks
This is a
question that has been puzzling me for years now. We know from historic
references and also artworks (heraldry, Smith’s painting) that the European
aurochs had frizzy, curly forelocks that we also see in many taurine cattle. In
wildtype coloured domestic cattle, these forelocks (or more precisely, the area
between the horns on the front head) show a colour that ranges from light blond
over orange-reddish, reddish-brown, dark brown to completely black as the rest
of the facial hair. Cis van Vuure considers lightly coloured forelocks in bulls
a discolouration that occurred after domestication (in wildtype coloured cows,
a lighter coloured area between the horns is a standard feature and also
supported by a cave painting in Lascaux). Written contemporaneous accounts suggest
that this area was coloured just like the rest of the face: Schneeberger
mentions the eel stripe, so he might have mentioned a special colour of the
forelocks as well if there was one (however, he did not mention the muzzle ring
either, although cave painting suggest its presence in wild European aurochs).
Von Herberstein was in possession of two belts made from aurochs forelocks, and
the colour of these forelocks was supposedly black based on his descriptions. North
African engravings showing the African subspecies depict bulls with a light
colour saddle on its back, in at least one case even the light muzzle ring (see
Frisch 2010; I am not referring to those tomb paintings that most likely show
domestic cattle described in van Vuure 2005). Again, if these bulls had
forelocks of a special colour, they might have drawn them just as the colour
saddle and muzzle ring. Furthermore, the aurochs, or at least black bulls, are
popular symbols in heraldry all over Europe, but not a single emblem shows a bull
with lightly coloured forelocks.
Furthermore,
lightly coloured forelocks might correlate with a reduced sexual dichromatism
or at least a reduction of melanisation. Light forelocks often correlate with a
colour saddle in bulls, f.e. in less melanised breeds such as
Alistana-Sanabresa and Cachena, while blond forelocks are never to be found in
a dark breed such as Sayaguesa. All cases of bulls with a colour saddle that I
have seen so far show lightly coloured forelocks, whereas in Maronesa, one of
the few breeds with a well marked sexual dimorphism, most bulls have either
black or dark forelocks, and never a saddle. Also Heck lineages with an (by the
breed’s standard) acceptable dichromatism show bulls with mostly black or dark
forelocks (I am thinking of the herds at Hellabrunn, Tierpark Haag, the Neandertal
and former Wörth herd), with some exceptions. There are a number of Lidia bulls
that show blond forelocks, and Lidia is, just like Heck cattle, heterogeneous
also in terms of sexual dichromatism.
Gaurs and
Banteng also a have lighter coloured area between the horns. In the Java
Banteng, which is the extant bovini with the most strongly marked sexual dichromatism,
the light area is not part of the coat colour, but actually a keratinized area.
The gaur has a very reduced sexual dimorphism – but not completely absent, you
can still see that cows usually tend do be not quite as dark and blackish as
the bulls are. Both sexes have lightly coloured hair between the horns. One
could argue now that having a light area between the horns therefore is a
plesiomorphic condition that the wild ancestors of taurine and zebuine cattle
must have had as well. But this must not necessarily be the case; white
muzzles, or eye rings as much as dorsal stripes are all characters that
originated multiple times but perhaps have the same underlying genetic
mechanisms (note however that the dorsal stripe in horses and bovines are
different).
While it is
just a speculation that lightly coloured forelocks in bulls are the result of
reduced sexual dimorphism, evidence does not support this trait for wild
aurochs bulls. All sources suggest that the forelocks of the aurochs were of a
dark or black colour, so van Vuure might well be right with considering lightly
coloured forelocks a discolouration that occurred after domestication. But the
data is in my opinion not comprehensive and precise enough to rule out this
trait for wild aurochs, due to the uncertainty it should also not be bred
against in breeding projects.
But if I
had to pick only one colour for the restoration of the forelocks of a wild
European bull, I would take black or dark forelocks, which is the colour I
usually use.
Mane
Some of you
might already be familiar with my idea that at least the European aurochs had a
kind of “mane” additionally to the frizzy, curly forelocks between the horns
because of a post in 2015. By “mane” I do not mean an opulent mass of hair such
as bison have, but rather just curly, perhaps only slightly longer, hair on the
head, neck and perhaps also shoulder area. This trait would be present in bulls
only, while curly forelocks can be present in both sexes. Actually a lot of
domestic bulls show such a “mane”, though to a variable extent. I came up with
the idea that it might be a functional aurochs trait when I read that this
“mane” (which is also where I got the name for it from) is suspected to protect
a Chillingham bulls’ skin during fight from the horns of the opponent, because
these areas are the most exposed during such a combat. Then I noticed that a
number of Oostvaardersplassen bulls actually have this kind of mane too, while
I have seen barely one such a case for Heck cattle outside the OVP. So this
might suggest that there is some kind of selective advantage for this trait,
although it is only speculative. Lidia is another example for a breed were we
find some bulls with a prominent “mane”.
Curly hair
is a typical bull feature, and the mane was not necessarily that eye-catching
that historic witnesses must have mentioned it. That is also why I gave my
aurochs bull model from 2014 curly hair on face, neck and throat, and I think I
will do so again when doing my next aurochs model. However, only preserved
aurochs skin, a notion in historic references or contemporaneous artistic
impressions can proof if some bull aurochs had such a mane. The various spots
on neck and face of two of the Lascaux bulls (the line drawings) might indicate
such curly hair, but that is only a guess of mine.
Aureole around
the eye
This
provokes the following questions: Were aureoles present in wild aurochs too? If
so, was it a general trait or dependent on regional variation, and was it
limited to one sex in adulthood?
Artistic
depictions of aurochs do not suggest the presence of ocular aureoles. There is
just one case, the painting of a black male aurochs at Lascaux, that shows a
white ring around the eye. But it is unknown whether the artist really wanted
to depict an eye ring or merely intended to implicate the presence of the eye. CharlesHamilton Smith’s aurochs painting has a slim white ring around the eye that might be
interpreted as an aureole, but this is only a second-hand artwork based on an
artwork itself. Apart from those two cases, no artistic representation of the
aurochs indicates the presence of eye rings, neither do any historic
references.
This and
the fact that only bulls that otherwise display neotenic traits and very small
size have eye rings as adults makes it unlikely to me that at least the
European and African subspecies had such aureoles as grown males. But for cows,
it seems like an open question to me whether at least some of them had them or
not. I tend to think that grown European female aurochs usually did not have light
eye rings, mainly because there is no mention of it and none of the artistic
depictions show them (I am thinking of coloured cave paintings). In the end, we cannot know whether some wild
aurochs cows (and also bulls) had this trait or not, and if it even was a
general characteristic for certain populations or subspecies.
It turns
out that even the white muzzle ring or mealy mouth is not that solidly
supported by the data either. There are no written accounts for it that I know
of. However, a number of cave paintings show it, or at least point to it, and
also Smith’s aurochs shows a reduced one (OK, here goes the same as for the eye
ring). But what is also striking is that it is a fixed, permanent trait of
nearly all wildtype coloured cattle on this world; there are only a few
exceptions where the muzzle ring is either strongly reduced or barely visible
due to some modifiers, but basically it is always present in E+//E+ cattle. So it should have been in
wild aurochs too. However, it could have been the case some individuals,
especially bulls, that it was reduced or even very reduced when they aged, so
that the white area might have been restricted to the upper lips and chin – the
way we see it in a number of taurine bulls, Gaurs and Banteng. In such
individuals, the “mealy mouth” would not have been such an obvious trait that it
would be considered worth mentioning anymore. Perhaps such a reduced white
muzzle was even the case in fully grown (European?) aurochs bulls. But that is
speculation.
Colour
shades in cows
This covers
two aspects: the amount of eumelanisation (how much black is in the coat
colour) and pheomelanisation (when is the colour so faint that it has to be
considered a domestic dilution).
Wildtype
coloured cows show a spectrum from almost uniformly light brown over darkening
from head, neck and legs and subsequently the lateral side of the trunk until
the whole body is dark brown/black except for a more or less large light colour
saddle – if that saddle is absent, the cow is coloured like a bull should be.
So, which
state in this continuum is the “correct” one, at least for European aurochs? We
cannot say. Artistic depictions, even the Lascaux cave alone, support the whole
spectrum. It shows, among more detailed figures, cows that are drawn uniformly
brown, sometimes only as lines, which might either indicate that the
individuals they are based on were of that uniformly brown colour or the artist
did not intend to reproduce its colour more detailed. The will to represent the
animals accurately is always a problem for artistic references; if someone,
say, spotted a mufflon and drew or described it being just “brown”, he might
consider that sufficient, although the coat colour of a mufflon is of course
more facetted. That’s also the case with Schneeberger’s report, where the cows
are simply said being of the colour of calves (“chestnut”, “blackish brown”, “dark
brown” etc.). There are a number of Heck and Maronesa cows those colour is of a
more or less uniformly dark chestnut brown colour, which might fit what
Schneeberger had in mind.
 |
| Maronesa and a Heck cow from Wörth; photo of the Maronesa cow by Goncalo Figueira, Wikipedia |
Lascaux
however also includes more defined representations of cow colours, such as very
dark cows with a red colour saddle. And just as there are cow depictions
completely lacking black, there is also one that is almost completely black with
a very narrow colour saddle at Lascaux. This colour is perfectly represented by
the Sayaguesa cow posted above (bottom row centre), or the Taurus cow at its
left. Schneeberger also mentions that very rarely, black cows appeared. This
notion is one of the reasons why black cows are usually tolerated in breeding
projects. A bull-coloured female aurochs might have been either the result of
the genetic diversity within the population, or of a twin birth. When a cow is
the twin of a bull, it might get infertile and develop the colour of the male
because it gets more male hormones than it should (I am not a developmental
biologist, so please excuse me for this imprecise language). If Schneeberger
was referring to results of such “accidents”, the legitimation for black cows
that are the result of lessened sexual dichromatism in breeding-back herds would
be gone. But in any case, I have always thought that in an ideal case the
portion of bull-coloured cows in such a herd should not be larger than 5-10%.
Regarding
all the non-bull-coloured shades that seemingly were present in the population,
it is the question whether they were distributed equally in the population or
if there was a prevalent type, if there was a regional gradient (the cave
paintings are all from southern Europe, but not the same time; so they might
represent aurochs of different genetic clusters). Artistic interpretations and written accounts
are too scarce, regionally limited and not precise enough to be nailed down to
one colour shade only, so that we can probably permit the full range for
breeding, or at least can not rule out one particular type.
What is
also striking is that there is a continuum from a rich, shiny red
pheomelanin-caused portion in the coat colour and the leucistic, colour-less grey
that results from the lack of pheomelanin. Alleles that cause these state are
called “dilution factors”. But since there is a continuum in crossbreed
populations at least, the question is: at which point are we dealing with the
presence of a dilution factor and which colour shade is still wildtype?
Historic
references as much as contemporaneous paintings all suggest shades like dark
brown, reddish brown, chestnut, light brown, ashy for aurochs cows. There is no
mention or depiction of beige tones or greyish tints, for example. The only way
to tell the individuals apart that carry the probable wildtype homozygous would
be to identify the modifier alleles that are responsible for the amount of
pheomelanin in the coat, because we are most likely dealing with more than one
locus and intermediate states, that should be the reason why we see a
continuum.
Colour saddle in
bulls
This is
another aspect of the aurochs’ coat colouration that can be a matter of debate.
Some argue that a light colour saddle in bulls was present or might have been
present in (European) aurochs, at least that we cannot rule it out. I use to
regard this trait as a sign of reduced sexual dimorphism just like a
bull-coloured cow, and there are no written or artistic references that support
the presence of a colour saddle in male European aurochs. On the contrary, most
references describe the aurochs as a black or at least very dark animal – be it
Plinius (“bos sylvestris niger”), the classification of the aurochs as
“suarzwild” (“black game”, together with wild boar) in the Lex Baiuvariorum AD
800, a figure on the Carta Marina by Olaus Magnus (who probably saw living
aurochs at Jaktorow), or von Herberstein, who held an aurochs skin in his hand
and described it “entirely black” except the dorsal stripe as much as
Schneeberger’s description and all cave paintings that both include only
completely black bulls with the dorsal stripe.
So the body
of evidence suggests that wild European bulls did not have a colour saddle, at
least there is no reason to think otherwise.
However, as
mentioned above, there are artistic depictions from Northern Africa that
suggest at least the African subspecies had a colour saddle.
Of course
it is harder to prove absence than it is to prove presence, but until there is
some evidence that European aurochs bulls were not always completely black
(except for the dorsal stripe and muzzle ring, and maybe forelocks), I assume
that a colour saddle in a bull is indicative of reduced sexual dimorphism and
something that should be avoided in breeding – at least for breeding bulls. So
far, a saddle in bulls is permitted in all breeding-back projects and breeds. I
think this is not effective for breeding bulls, but of course such a bull can
still be desirable because of other traits, it is always about balancing
traits.
As you see,
a large part of these open questions or uncertainties concern coat colour,
since the morphology of the aurochs is well-known thanks to the comprehensive bone
material. I have also speculated that some colour types we see in domestic
cattle might have evolved in the aurochs already, such as solid black all over
the body (Ed allele) in
wild B. primigenius primigenius, or
it might have gotten transferred from domestic populations into wild ones, or
that the dilution alleles that cause the greyish colour of many zebuine cattle
as much as in Podolian cattle might be a wildtype trait of B. p. namadicus. There is no evidence pointing to that, these are
just thoughts that I consider not totally implausible.
One could,
just like a number of authors did it with horses, test aurochs bone material
for coat colour alleles. As a test to see whether those alleles we consider
wildtype were indeed present in the wildtype and to see whether unexpected
variants, like Ed, were present or not in wild populations. It could
also be used to rule out the proposal of a Chillingham cattle-like spotted
pattern for predomestic aurochs (a suspicion that is based on line drawings
from Lascaux – but I consider this evidence not compelling at all).
Since a
number of cattle modifier loci and alleles are only speculative, some of them
would have to be identified before looking for them in aurochs material. I am
not that optimistic that such a study would be conducted in the near future however,
since the interest in cattle and cattle coat colours is not nearly as big as
the interest for horses. Nevertheless, the data gained from such a study could
be helpful for breeding projects. For example, once all the dilution modifier
alleles are identified, cattle from breeding projects could be tested for
those. In this way, breeding bulls carrying recessive dilution alleles could be
avoided.
A while
ago, I illustrated what a Chillingham-coloured aurochs, solid black aurochs and
my Indian aurochs bull with Agouti dilutions seen in Podolian cattle would look
like. Again, I am neither proposing that aurochs of these colour variants
existed nor am I “believing” it, I am just illustrating possibilities.
Walter Frisch: Der Auerochs: Das europäische Rind. 2010.
Cis van Vuure: Retracing the Aurochs - History, Morphology and Ecology of an extinct wild Ox. 2005