Post on 20-Jan-2017
Stable isotope insights (d18O, d13C) into cattleand sheep husbandry at Bercy (Paris, France,4th millennium BC): birth seasonality andwinter leaf foddering
Marie Balasse, Loıc Boury, Joel Ughetto-Monfrin and Anne Tresset
Bercy is a prehistoric village sited by the Seine river (Paris, France), whose main period of
occupation was dated to the very beginning of the 4th millennium BC. The animal subsistence
economy relied heavily on cattle husbandry, complemented by other species including sheep.
Cattle and sheep isotopic history (d13C, d18O) was investigated at the seasonal scale, through
sequential sampling in tooth enamel, providing new insights into seasonality of birth and diet.
Sheep were lambing in mid-spring, only slightly later than expected from what is observed
nowadays in temperate Europe at similar latitude. Cattle were born over a period spanning
approximately six months, which was an unexpected result compared with a two to three months
calving period in free-ranging cattle populations. The extension of the calving period might have
been related to seasonal food supplementation. Some cattle and some sheep fed on a 13C-
depleted resource in winter, potentially leafy fodder. A direct consequence of an extended
calving period would be the availability of cow milk, which would have covered the whole year at
Bercy. This is important information in a context where the exploitation of cattle milk by the human
community was highly suspected from the demographic management of the herd.
Keywords: cattle, sheep, carbon and oxygen stable isotope ratios, tooth enamel, birth seasonality, fodder
Introduction
Bercy is a large prehistoric village site sited on a bank
of the Seine river (Paris, France), excavated during
the 1990s under the direction of P. Marquis and Y.
Lanchon (Marquis 1991; Lanchon et al. 2000). Its
main occupation, attributed to the Chasseen septen-
trional culture, was dated to the very beginning of the
4th millennium BC. Excavation of the adjacent pa-
leochannel produced rich assemblages of faunal and
botanical remains. A pluridisciplinary research was
conducted in the 1990s in order to investigate the
environmental context of this agro-pastoral settlement
and evaluate its impact on the milieu. From paly-
nological (Leroyer 1998), anthracological (Pernaud
1997) and carpological (Dietsch 1996; Dietsch-
Sellami 2001) data, at the time of the Chasseen occu-
pation, the river bank was characterised by a riverine
forest dominated by the alder. A wet meadow had
developed on the marshy soils of the valley floor,
with a high frequency of ruderal species suggesting
that it was used for pasture. Alluvial terraces were
covered with a dense oak tree forest exploited by the
human community for fire wood and partly cleared
for agricultural purpose.
The animal subsistence economy (Tresset 1996;
1997) relied heavily on cattle husbandry, complemen-
ted by the raising of pig, sheep and goat. The hunted
wild fauna, dominated by red deer, also included roe
deer, aurochs, wild pig and small furry game.
Documented on the basis of tooth eruption and wear
stages, the mortality profiles of domestic animals
Marie Balasse (corresponding author), Joel Ughetto-Monfrin and AnneTresset, Museum national d’Histoire naturelle USM 303/CNRS UMR 7209‘Arche ozoologie, Arche obotanique: Socie t e s, Prat iques etEnvironnements’, Departement Ecologie et Gestion de la Biodiversite,case postale 56, 55 rue Buffon, 75005 Paris, France, e-mail: balas-se@mnhn.fr; Loıc Boury, Universite de Strasbourg/CNRS UMR 7044‘Etude des civilisations de l’Antiquite’, ANTEA Archeologie, 11 rue deZurich, 68440 Habsheim, France.
� Association for Environmental Archaeology 2012Published by ManeyReceived July 2011; revised manuscript accepted January 2012DOI 10.1179/1461410312Z.0000000003 Environmental Archaeology 2012 VOL 17 NO 1 29
show that pigs and small stock were culled mainly
when reaching a good weight and not maintained to
older ages, suggesting a strategy oriented essentially
towards meat production. Cattle were raised for meat
but also for milk, as suggested by the presence of old
individuals, presumably cast milk cows, and a very
high mortality of young individuals reflecting prob-
ably a post-lactation slaughter (Tresset 1996; 1997;
Balasse et al. 1997; 2000; Balasse and Tresset 2002).
Previous stable isotope analyses of bone collagen
of large herbivores from Bercy provided a first
glimpse of the occupation of the landscape by wild
and domestic herbivores. From the d13C values
measured in bone collagen from these animals,
potentially reflecting the feeding on closed forest
understorey vegetation, it was suggested that domes-
tic cattle were raised in open pastures whereas coeval
aurochs fed within the dense forest (Balasse et al.
2000; Drucker et al. 2008). Red deer and roe deer had
a more opportunistic feeding strategy along the forest
edge (Drucker et al. 2008). Prolonging this effort in
the study of the stable isotope ecology of the
Neolithic settlement of Bercy, the present study
focuses on domestic cattle and sheep. Their isotopic
history (d13C, d18O) was investigated at the seasonal
scale, through sequential sampling in tooth enamel,
providing new insights into seasonality of birth and
diet.
Investigating birth seasonality in Neolithicdomestic stock
The onset and the length of the birth period in
domestic stock influences the annual cycle of pastoral
tasks. In mammals, synchronisation of the breeding
cycle to the most appropriate time for survival of
the young is driven by environmental variables. In
domestic sheep, within the period of fertility defined
by the photoperiodic cycle (Karsch et al. 1984),
the onset and the length of the breeding period
are determined by climatic, environmental (weather
conditions, food availability) and genetic parameters
(Hafez 1952; Lincoln et al. 1990; Rosa and Bryant
2003). Cattle do not experience anoestrus and are
fertile all the year round. However, in extensive
conditions their breeding cycle is driven by environ-
mental variables including the vegetation annual
cycle (Lecomte and Le Neveu 1986; Reinhardt et al.
1986). Although it is most likely that in Neolithic
temperate Europe the births of domestic cattle and
sheep were seasonal, how restricted the birth period
was still needed to be defined. Calving also coincides
with the initiation of lactation and this parameter
might have been especially important in a context of
dairying, as strongly suggested for cattle at Bercy
(Tresset 1996; 1997; Balasse et al. 1997; 2000).
Birth seasonality can be investigated from tooth
remains using analysis of enamel oxygen isotope
composition (Bryant et al. 1996a; 1996b). The oxygen
isotope composition (d18O) of the skeleton calcium
phosphate (bioapatite) is mainly linked to that of
ingested water, i.e. indirectly meteoric water (Land
et al. 1980; Longinelli 1984; Luz et al. 1984; D’Angela
and Longinelli 1990; Delgado Huertas et al. 1995). At
high and middle latitudes, the d18O of precipitation
varies seasonally with ambient temperature (Gat
1980). The seasonal variations are recorded in tooth
mineral during development and are not remodelled
once enamel mineralisation is completed. Recon-
struction of the seasonal cycle is therefore possible by
performing a sequential d18O analysis along the tooth
growth axis (Koch et al. 1989; 1995; Fricke and
O’Neil 1996; Stuart-Williams and Schwarcz 1997;
Kohn et al. 1998; Sharp and Cerling 1998; Sharma
et al. 2004; Nelson 2005; van Dam and Reichart 2009;
Bernard et al. 2009). Because the timing of tooth
development is fixed within a species, seasonality of
birth can be investigated through the study of inter-
individual variability in d18O changes along tooth
crown (Balasse et al. 2003; Nelson 2005; Balasse and
Tresset 2007; Britton et al. 2009; Henton et al. 2010;
Towers et al. 2011).
Investigating leaf foddering in Neolithictemperate Europe
Sequential sampling of tooth enamel also permits to
investigate animal diet at the seasonal scale, from the
analysis of carbon stable isotope composition (d13C)
of bioapatite. The potential of stable carbon isotope
analysis to investigate seasonality of diet is not wide,
especially in North-western Europe where C4 plants
are very rare (today: up to 1?2% of species, including
up to a quarter of invasive species originating in other
continents and mostly recently introduced to Europe;
Pyankov et al. 2010). However, it can still be used to
investigate seasonal consumption of plants from
closed areas, where the canopy effect would result
in lower d13C values (van der Merwe and Medina
1991), inherited in animals feeding on them.
The use of tree leaves to feed domestic cattle and
small stock was widespread in Europe until recent
history from Norway to the Mediterranean area, to
compensate for restricted availability of grass during
dry summers or snowy winters and/or over periods
of stalling (see Troels-Smith 1960; Rasmussen 1990;
Halstead and Tierney 1998; Thiebault 2005 for
archaeobotanical evidence and Lucas 1989 and
Balasse et al. Birth seasonality and winter leaf foddering
30 Environmental Archaeology 2012 VOL 17 NO 1
Kelly 1997 for historical accounts). The practice
was directly evidenced at middle Neolithic sites in
Switzerland, where botanical remains were retrieved
in cattle and small stock dung levels, attesting the use
of twigs and leaves from various tree species, some of
which might have been pollarded especially for the
purpose (Rasmussen 1989; 1990; 1993; Akeret et al.
1999). The common tree taxa recovered at these sites
(Corylus, Alnus, Betula, Salix, Fraxinus, Tilia) are
typical of open forest and their consumption might
not be detected through a d13C analysis. Never-
theless, Hedera helix L. and Ilex aquifolium L., men-
tioned in the early Irish literature (Kelly 1997) could
be detected provided they have been cut in deeper
forest, which is likely. The use of deciduous oak trees
as leafy fodder is also reported in recent history
(Halstead and Tierney 1998) and its over-representa-
tion in the anthracological assemblages of the early
and middle Neolithic horizons of sheepfold rock-
shelters from the alpine and circum alpine area in
France was interpreted as possibly reflecting the
harvesting of leafy fodder to feed caprines (Thiebault
2001; 2005; Delhon et al. 2008). When harvested in
a dense forest, leafy fodder might be marked by
the canopy effect. Although the use of leafy fodder
and the choice of the tree species are submitted to
cultural choices and environmental availability, this
possibility could be addressed at Bercy, where d13C
measured in bone collagen from wild large herbivores
(Drucker et al. 2008) suggested the presence of a
closed canopy in the surrounding environment, while
the presence of a dense oak forest was evidenced from
pollen remains (Leroyer 1998). Although previous
bone collagen d13C analysis suggested the feeding
of domestic stock in open areas, sequential stable
isotope analysis in teeth would permit the question of
leaf foddering to be investigated at a seasonal scale.
Material and methods
Five hemi-mandibles from sheep and ten hemi-
mandibles from bovines were selected, belonging to
different individuals. Sheep present at Bercy are
securely domestic, as the species has no wild ancestor
in Europe (Poplin 1979; Tresset et al. 2009). Within
the caprine tooth rows, they were distinguished from
goats from morphological criteria (Balasse and
Ambrose 2005; Payne 1985; Helmer 2000; Halstead
et al. 2002). Both wild and domestic bovines occur
in the faunal assemblage of Bercy; this has been
suspected from the osteometric analysis (Tresset
1997) but also demonstrated on molecular grounds
(Edwards et al. 2004; Bollongino et al. pers. comm.).
Assessing the wild or domestic status of a bovine
from a tooth row basing on osteometric criteria only
is problematic. An attempt was made to use size
criteria on the third molar. The length and the width
of the crown were measured on 47 lower third molars
(M3) from Bercy. Results are reported in Fig. 1. The
M3 lengths range from 30?5 to 45?6 mm and the
widths from 14?5 to 19?1 mm. The five M3, the length
of which is less than 34 mm, are characterised by the
atrophy of the third lobe. BQSBos2M3 is one of
them. All other M3 included in the stable isotope
study have a length comprised between 35 and 40 mm
and a width comprised between 15 and 17 mm
(Fig. 1), except for BQSBos11M3, which is the largest
of the whole assemblage with a 45?6 mm length and a
19?1 mm width. It is the most likely candidate for a
wild status, although we are fully aware that the size
criteria might sometimes be misleading for the dis-
tinction between wild and domestic bovines (Vigne
et al. 2007; Tresset et al. 2009).
The sampling was performed on the posterior lobe
of the M2 in sheep and on the anterior lobe of the M3
in cattle. Enamel surfaces were cleaned with a gentle
brush and the external surface removed by drilling
with a tungsten drill bit. A sequential sampling was
performed by drilling with diamond burr on the
buccal side of the teeth, perpendicularly to the crown
growth axis, going through the whole thickness of the
Figure 1 Results from measurements of the length and
width of cattle lower third molars. Bos11M3 is
the largest tooth from the assemblage Figure 2 Enamel sampling procedure in cattle (a) and
sheep (b) third and second molars respectively
Balasse et al. Birth seasonality and winter leaf foddering
Environmental Archaeology 2012 VOL 17 NO 1 31
enamel layer (Fig. 2). Because of the complexity
of the enamel deposition and maturation processes,
this sampling procedure does not permit isolation of
discrete growth increments and time segments, but
the sequence measured was shown to be chronolo-
gical in sheep and cattle teeth, as evidenced by
unambiguous seasonal cycles in the oxygen isotope
values (Balasse 2003; Balasse et al. 2003). Enamel
samples weighed between 4?5 mg and 8 mg. The
number of samples taken from one tooth varies from
18 to 20 on the cattle third molars, 13 to 18 on the
sheep second molars, for a total number of 267
samples.
Enamel powder was treated for bioapatite extrac-
tion as described in Balasse et al. (2002). Enamel was
treated with sodium hypochlorite 2–3% (24 h) to
remove organic matter, and then with 0?1 M acetic
acid (4 h, 0?1 ml/mg) to remove exogenous carbonate.
Bioapatite samples weighing around 600 mg were
reacted with 100% phosphoric acid at 70uC in
individual vessels in an automated cryogenic distilla-
tion system (Kiel IV device) interfaced with a Delta V
Advantage isotope ratio mass spectrometer. Over the
period of analysis of these bioapatite samples, 155
analyses of our laboratory internal carbonate stan-
dard (Marbre LM) gave a mean d13C value of
2?13¡0?02 % (1s) (theoretical value normalised to
NBS 19 5 2?13 %) and a mean d18O value of
21?79¡0?07% (1s) (theoretical value normalised to
NBS 19 5 21?83 %). The analytical precision within
each run, calculated from 5 to 12 measurements of
the standard Marbre LM, varies from 0?01 to 0?03%for d13C and from 0?03 to 0?07% for d18O.
Results
Results are reported in Tables 1 and 2 and Figs 3 and
4. Stable oxygen isotope values vary between 26?9
and 21?9% in cattle and between 27?6 and 21?2%in sheep. In both species, the d18O values show
sinusoidal variations with time along tooth crown,
with amplitude of variation of 1?5 to 4?0% in cattle
and 2?5 to 4?8% in sheep. They most likely reflect the
seasonal cycle in ambient temperature. A whole
annual cycle is recorded over approximately 40 to
50 mm in the cattle M3 (Fig. 3). In sheep, the M2
crowns were worn up to a height of approximately 25
mm or less. The cycle measured over this length was
incomplete; half an annual cycle was measured over
approximately 15 mm (Fig. 4). Stable carbon isotope
values vary between 214?7 and 211?6% in cattle and
between 215?3 and 210?3% in sheep. Within a
tooth, the amplitude of variation is between 0?8 and
2?0% in cattle and between 1?5 and 2?7% in sheep.
When seasonal changes are recorded in cattle teeth,
the highest d13C values occur in the summer and the
lowest in the winter. The same trend is observed in
the sheep teeth.
DiscussionCattle birth seasonality
Birth seasonality is assessed from inter-individual
variability in the position in the tooth crown where
the lowest and highest d18O are measured. In order to
identify these positions while erasing analytical noise,
the measured data sequences were modelled using the
following equation mainly based on a cosine function
(Balasse et al. 2011):
d18Om5A. cos (2P? (x-x0)/X)zM
where:
d18Om is the modelled d18O;
x is the distance from enamel-root junction;
X is the period (in mm), corresponding to the
length of tooth crown potentially formed over a
whole annual cycle;
A is the amplitude (5 (max-min)/2) (in %);
x0 is the delay (mm), which depends on the time of
the year when tooth growth started; d18O attains
maximum value when x 5 x0;
M is the mean (5 (maxzmin)/2) expressed in %.
Fig. 5 shows an example of the model for
BQSBos1M3 detailing the parameters. The best fit
of the model parameters to the measured data was
determined using an iterative method and a mini-
misation of the sum of the square of the difference
between the model and the measurements (method of
least squares). Results from the calculation of the best
fit for combined variations of X, A, x0 and M are
shown in Table 3 and in Fig. 3. The fitting of the
model to the dataset is estimated using the Pearson’s
correlation coefficient. This coefficient was always
>0?94 (Table 3), demonstrating that the model is in
each case very close to the dataset. The period X
varies from 39?4 to 44?7 mm for most individuals.
BQSBos5M3 and BQSBos7M3 differ from the others
with respectively shorter (31?0 mm) and larger (57?3
mm) periods, although results from the modelling of
BQSBos7M3 may not be accurately reflecting the
cycle (the first three samples had to be excluded from
the calculation because they would force the model
to unsuitable solutions). Variability in the modelled
period reflects variability in growth rate, related to
tooth size. It is necessary to remove this variability
before comparing the position in tooth crown where
the lowest and highest d18O values were measured in
the different specimens. Because the period represents
always the same duration of time (one year) in all
Balasse et al. Birth seasonality and winter leaf foddering
32 Environmental Archaeology 2012 VOL 17 NO 1
Tab
le1
Sta
ble
carb
on
(d13C
)an
do
xyg
en
(d18O
)is
oto
pe
valu
es
measu
red
into
oth
en
am
el
bio
ap
ati
tefr
om
catt
lelo
wer
thir
dm
ola
rs(M
3).
d13C
an
dd1
8O
valu
es
are
exp
ressed
in%
.S
am
ple
sa
relo
ca
ted
ine
ac
hto
oth
cro
wn
by
the
dis
tan
ce
fro
mth
ee
na
me
l–
roo
tju
nc
tio
n(m
m).
D5
intr
a-t
oo
tha
mp
litu
de
of
va
ria
tio
n
Sam
ple
mm
d13C
VP
DB
d18O
VP
DB
Sam
ple
mm
d13C
VP
DB
d18O
VP
DB
Sam
ple
mm
d13C
VP
DB
d18O
VP
DB
Sam
ple
mm
d13C
VP
DB
d18O
VP
DB
sam
ple
mm
d13C
VP
DB
d18O
VP
DB
BQ
SB
os1
M3-1
49
?52
12
?82
5?7
BQ
SB
os2
M3-1
47
?42
13
?72
5?5
BQ
SB
os3
M3-1
45
?72
12
?72
4?6
BQ
SB
os4
M3-1
46
?92
12
?62
5?4
BQ
SB
os
5M
3-1
46
?92
12
?62
5?4
BQ
SB
os1
M3-2
47
?32
13
?02
5?8
BQ
SB
os2
M3-2
45
?02
13
?72
5?8
BQ
SB
os3
M3-2
43
?62
12
?52
5?1
BQ
SB
os4
M3-2
44
?62
12
?72
5?5
BQ
SB
os
5M
3-2
44
?62
12
?72
5?5
BQ
SB
os1
M3-3
45
?22
13
?72
6?1
BQ
SB
os2
M3-3
42
?92
13
?92
5?7
BQ
SB
os3
M3-3
41
?32
12
?32
5?4
BQ
SB
os4
M3-3
42
?32
12
?72
5?6
BQ
SB
os
5M
3-3
42
?32
12
?72
5?6
BQ
SB
os1
M3-4
42
?92
13
?82
6?5
BQ
SB
os2
M3-4
40
?52
13
?82
6?1
BQ
SB
os3
M3-4
38
?92
12
?32
5?4
BQ
SB
os4
M3-4
39
?92
12
?62
5?4
BQ
SB
os
5M
3-4
39
?92
12
?62
5?4
BQ
SB
os1
M3-5
40
?82
14
?12
6?5
BQ
SB
os2
M3-5
38
?12
13
?92
6?1
BQ
SB
os3
M3-5
36
?72
12
?42
5?5
BQ
SB
os4
M3-5
37
?52
12
?52
4?8
BQ
SB
os
5M
3-5
37
?52
12
?52
4?8
BQ
SB
os1
M3-6
38
?42
14
?22
6?9
BQ
SB
os2
M3-6
35
?82
14
?12
6?9
BQ
SB
os3
M3-6
34
?22
12
?52
5?7
BQ
SB
os4
M3-6
35
?12
12
?42
4?5
BQ
SB
os
5M
3-6
35
?12
12
?42
4?5
BQ
SB
os1
M3-7
36
?32
14
?42
6?5
BQ
SB
os2
M3-7
33
?32
14
?22
6?4
BQ
SB
os3
M3-7
32
?02
12
?52
5?8
BQ
SB
os4
M3-7
32
?82
12
?32
4?1
BQ
SB
os
5M
3-7
32
?82
12
?32
4?1
BQ
SB
os1
M3-8
34
?22
14
?32
6?8
BQ
SB
os2
M3-8
30
?92
14
?42
6?0
BQ
SB
os3
M3-8
29
?72
12
?62
6?0
BQ
SB
os4
M3-8
30
?62
12
?02
3?7
BQ
SB
os
5M
3-8
30
?62
12
?02
3?7
BQ
SB
os1
M3-9
32
?02
14
?32
6?4
BQ
SB
os2
M3-9
28
?22
14
?02
6?4
BQ
SB
os3
M3-9
27
?42
12
?62
6?5
BQ
SB
os4
M3-9
28
?22
11
?92
3?5
BQ
SB
os
5M
3-9
28
?22
11
?92
3?5
BQ
SB
os1
M3-1
029
?92
14
?12
5?8
BQ
SB
os2
M3-1
025
?82
13
?92
5?6
BQ
SB
os3
M3-1
025
?22
12
?72
6?5
BQ
SB
os4
M3-1
026
?22
12
?02
3?7
BQ
SB
os
5M
3-1
026
?22
12
?02
3?7
BQ
SB
os1
M3-1
128
?02
13
?52
5?2
BQ
SB
os2
M3-1
123
?42
13
?42
4?5
BQ
SB
os3
M3-1
123
?22
12
?72
6?8
BQ
SB
os4
M3-1
123
?92
12
?12
3?5
BQ
SB
os
5M
3-1
123
?92
12
?12
3?5
BQ
SB
os1
M3-1
225
?52
13
?62
4?6
BQ
SB
os2
M3-1
221
?22
13
?32
3?9
BQ
SB
os3
M3-1
220
?82
12
?92
6?9
BQ
SB
os4
M3-1
221
?72
12
?12
3?7
BQ
SB
os
5M
3-1
221
?72
12
?12
3?7
BQ
SB
os1
M3-1
323
?42
13
?42
4?1
BQ
SB
os2
M3-1
318
?92
13
?22
3?6
BQ
SB
os3
M3-1
318
?82
12
?72
6?5
BQ
SB
os4
M3-1
319
?82
12
?02
3?9
BQ
SB
os
5M
3-1
319
?82
12
?02
3?9
BQ
SB
os1
M3-1
421
?52
13
?22
3?7
BQ
SB
os2
M3-1
416
?72
12
?92
3?4
BQ
SB
os3
M3-1
416
?52
13
?12
6?1
BQ
SB
os4
M3-1
417
?82
12
?12
3?9
BQ
SB
os
5M
3-1
417
?82
12
?12
3?9
BQ
SB
os1
M3-1
519
?52
13
?02
3?7
BQ
SB
os2
M3-1
514
?32
12
?92
3?5
BQ
SB
os3
M3-1
514
?52
13
?02
5?8
BQ
SB
os4
M3-1
515
?72
12
?12
4?3
BQ
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515
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BQ
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617
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4?3
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os2
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612
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612
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613
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613
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79
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BQ
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79
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BQ
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711
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SB
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87
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SB
os3
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87
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12
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BQ
SB
os4
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88
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5?6
BQ
SB
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SB
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SB
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08
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13
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D5
1?6
3?2
Balasse et al. Birth seasonality and winter leaf foddering
Environmental Archaeology 2012 VOL 17 NO 1 33
Sam
ple
mm
d13C
VP
DB
d18O
VP
DB
Sam
ple
mm
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VP
DB
d18O
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Sam
ple
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ple
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ple
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ple
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124
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124
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14
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os9
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116
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12
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os6
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222
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12
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os7
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222
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os8
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222
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13
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os9
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214
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13
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os6
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320
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12
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os7
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320
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2?0
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SB
os8
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321
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13
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3?0
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os9
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312
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418
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419
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13
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410
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13
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516
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516
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12
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os8
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517
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13
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58
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615
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Ta
ble
1C
on
tin
ue
d
Balasse et al. Birth seasonality and winter leaf foddering
34 Environmental Archaeology 2012 VOL 17 NO 1
Tab
le2
Sta
ble
carb
on
(d13C
)an
do
xyg
en
(d18O
)is
oto
pe
valu
es
measu
red
into
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en
am
el
bio
ap
ati
tefr
om
sh
eep
low
er
seco
nd
mo
lars
(M2).
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an
dd1
8O
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es
are
ex
pre
ss
ed
in%
.S
am
ple
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relo
ca
ted
into
oth
cro
wn
by
the
dis
tan
ce
fro
mth
ee
na
me
l–
roo
tju
nc
tio
n(m
m).
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intr
a-t
oo
tha
mp
litu
de
of
va
ria
tio
n
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ple
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ple
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ple
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ple
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ple
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23
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16
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22
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7?6
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16
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22
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4?6
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SO
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15
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12
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5?3
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SO
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19
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13
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6?3
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21
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7?0
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14
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?62
4?5
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SO
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20
?72
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4?1
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SO
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14
?02
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5?0
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SO
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17
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SO
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19
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13
?82
7?3
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SO
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19
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16
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7?2
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12
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14
?42
3?4
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SO
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2-6
18
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2?8
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SO
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11
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4?3
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15
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17
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7?1
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11
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2?7
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17
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10
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3?9
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SO
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14
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16
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?52
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10
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BQ
SO
vis
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16
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?32
1?6
BQ
SO
vis
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9?5
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vis
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13
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3?5
BQ
SO
vis
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2-9
15
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13
?22
6?0
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SO
vis
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8?6
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SO
vis
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15
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BQ
SO
vis
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BQ
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SO
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07
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13
?32
1?5
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SO
vis
3M
2-1
013
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1?2
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SO
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12
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SO
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112
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12
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16
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SO
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112
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16
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SO
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5M
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19
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BQ
SO
vis
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211
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SO
vis
2M
2-1
25
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BQ
SO
vis
3M
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211
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1?7
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SO
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25
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SO
vis
5M
2-1
28
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2?3
BQ
SO
vis
1M
2-1
310
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12
?22
4?5
BQ
SO
vis
2M
2-1
34
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?42
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SO
vis
3M
2-1
39
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SO
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34
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3?9
BQ
SO
vis
5M
2-1
36
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2?3
BQ
SO
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1M
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49
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4?3
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SO
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42
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13
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3?4
BQ
SO
vis
3M
2-1
48
?72
13
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1?9
BQ
SO
vis
4M
2-1
43
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10
?32
4?3
BQ
SO
vis
5M
2-1
45
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2?5
BQ
SO
vis
1M
2-1
57
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BQ
SO
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2M
2-1
51
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3?7
BQ
SO
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3M
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57
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BQ
SO
vis
4M
2-1
52
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10
?92
3?9
BQ
SO
vis
5M
2-1
54
?42
12
?02
3?0
BQ
SO
vis
1M
2-1
66
?62
11
?62
4?3
D5
1?5
4?3
BQ
SO
vis
3M
2-1
66
?52
13
?22
2?8
D5
2?7
2?5
BQ
SO
vis
5M
2-1
63
?62
12
?22
2?8
BQ
SO
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2-1
75
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11
?82
4?3
BQ
SO
vis
3M
2-1
75
?22
13
?42
3?3
D5
BQ
SO
vis
1M
2-1
84
?22
12
?02
4?2
BQ
SO
vis
3M
2-1
84
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14
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4?3
BQ
SO
vis
1M
2-1
93
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11
?82
4?2
BQ
SO
vis
3M
2-1
92
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14
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4?4
BQ
SO
vis
1M
2-2
01
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12
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4?4
BQ
SO
vis
3M
2-2
01
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15
?32
5?1
D5
2?5
3?4
D5
2?2
4?1
Balasse et al. Birth seasonality and winter leaf foddering
Environmental Archaeology 2012 VOL 17 NO 1 35
individuals, it was used to normalise the measured
distances. In Fig. 6, the location in the tooth crown
where the highest d18O values occur for each
individual was normalised with their respective
period X (x0/X). Values for x0/X are evenly distrib-
uted between 0?12 and 0?62 (Table 3 and Fig. 6a),
meaning that the highest d18O values were measured
at 12 to 62% of the end of the recorded periodic cycle,
the end being defined as when the cycle reaches the
enamel-root junction. At a monthly scale (a whole
period represents 12 months), a delay of approxi-
mately six months over the annual cycle separates the
measure of the highest d18O values in BQS Bos3M3
and BQS Bos9M3 (Fig. 6b), meaning that if the
Figure 3 Results from sequential analysis of stable carbon (d13C, black symbols) and oxygen (d18O, white symbols) iso-
tope ratios in cattle tooth enamel bioapatite. Samples are located in each tooth crown by their distance from
the enamel-root junction (erj). The grey line shows the modelled d18O values
Balasse et al. Birth seasonality and winter leaf foddering
36 Environmental Archaeology 2012 VOL 17 NO 1
population analysed in this study is representative of
the herd, cattle births were occurring over approxi-
mately six months.
The dataset acquired at Bercy was then compared
to results obtained following the same analytical
procedure on cattle teeth from the Neolithic farm-
stead of the Knap of Howar (Orkney, ca. 3600 BC;
Ritchie 1983), using the dataset published in Balasse
and Tresset (2007). Although only five individuals
could be analysed from this assemblage, interpreta-
tion of the raw data suggested a strong seasonality of
birth over a very restricted time of the annual cycle
(Balasse and Tresset 2007). From the model, the
period calculated for the cattle M3 from the Knap of
Howar varies from 34?2 to 46?8 mm, reflecting again
significant variability in tooth size and growth rate
(Table 3). Fig. 6c compares individuals after normal-
isation of x0 with the period X calculated for each
individual. At the Knap of Howar, the highest d18O
values in cattle M3 were measured at 45 to 56% of the
end of the periodic cycle recorded in the tooth. Over
the annual cycle, the birth of these five individuals
was distributed over less than two months (Fig. 6d).
Compared to the Knap of Howar, the Bercy
dataset therefore appears to reflect a less restricted
period of birth for cattle. As discussed elsewhere
(McCormick 1998; Balasse and Tresset 2007), con-
straining climatic conditions might explain the very
restricted birth period observed at the Knap of
Howar, which might either have actually led to a
restricted period of births and/or might have resulted
in the death of the calves born unseasonably: the
analyses performed on the third molar only reflect the
birth season of cattle who survived their second year,
over which the tooth is formed (Brown et al. 1960).
Observations on primitive cattle breeds free ranging
Figure 4 Results from sequential analysis of stable carbon (d13C, black symbols) and oxygen (d18O, white symbols) iso-
tope ratios in sheep tooth enamel bioapatite. Samples are located in each tooth crown by their distance from
the enamel-root junction (erj). The grey line shows the modelled d18O values
Figure 5 Application of the model to the d18O dataset
measured in BQS Bos1M3. M 5 mean; A: ampli-
tude; X: period; x0: delay
Balasse et al. Birth seasonality and winter leaf foddering
Environmental Archaeology 2012 VOL 17 NO 1 37
in extensive conditions with no control of breeding
in Northern France (Normandie: Lecomte and Le
Neveu 1986) and in Scotland (Reinhard et al. 1986)
show that calving occur over two to three months in
these populations, from May to July in Northern
France, from May to June in Scotland. In this regard,
a calving period spanning approximately six months
at Bercy seems relatively long, and might have been
related to the domestic status of the herd. A direct
consequence of a calving period extended over six
months would be availability of cattle milk all the
year round if a 6 to 7 months lactation is assumed for
Neolithic primitive domestic females (Peske 1994;
Tresset 1996).
Sheep birth seasonality
The same modelling procedure was applied to the
d18O values measured in sheep teeth. Results from the
calculation of the best fit for combined variations of
X, A, x0 and M are shown in Table 3 and in Fig. 4.
Values for x0/X vary from 0.19 to 0.43 (Table 3 and
Fig. 7a) and average 0?31. This figure is very similar
to the pattern observed on the second molar of a
dataset of ten modern sheep from a Shetland cross-
breed, born between the end of April and the
beginning of May, for which x0/X averages 0?28
(Balasse et al. 2012; Fig. 7b). This suggests that the
births of the analysed sheep from Bercy were centred
around that time. This is only slightly later than what
is observed nowadays in temperate climate and at
very close latitude: the birth period of free rang-
ing Shetland sheep in the nature reserve of Ma-
rais Vernier (Normandie, Northern France) occurs
between mid March and the end of April (Lecomte
and Le Neveu 1986).
Seasonal changes in cattle and sheep diet d13C
Stable carbon isotope values as low as 214?7% in
cattle and 215?3% in sheep were measured season-
ally in tooth enamel. Considering a 14?1% 13C-
enrichment (e*) between diet and bioapatite (Cerling
and Harris 1999), such values would correspond to
d13C values of 228?4% and 229?0% respectively for
diet. These end-members may be underestimated due
to a dampening effect caused by a delay in enamel
mineralisation (Balasse 2002; 2003; Passey and Cer-
ling 2002). This is considerably lower than the modal
d13C values of 225?6% expected for pre-industrial C3
plants in open areas (using a modal value of 227%for modern C3 plants: O’Leary 1988; Tieszen and
Boutton 1988; corrected by z1.4 % for the fossil fuel
effect: Freyer and Belacy 1983; Stuiver et al. 1984;
Friedli et al. 1986; Leavitt and Long 1986). In
temperate environments, low d13C values may be
attributed to the canopy effect, i.e. consumption of
vegetation grown in a dense forest. Kohn (2010)
recently recommended the d13C value of 231?5% as a
cut-off indicating the understories of closed-canopy
forests. However, d13C values measured on modern
roe deer bone collagen in the Dourdan deciduous
forest (France) average 224?7% (n 5 18, Rodiere
et al. 1996), from which, considering a 5% 13C-
enrichment between diet and collagen (Ambrose
1993; van der Merwe 1989), an average value of
229?7% can be estimated for diet. This is slightly
higher than the cut-off values recommended by
Table 3 Results from the calculation of the best fit (method of least squares) for combined variation of X (period), A(amplitude), x0 (delay) and M (mean) when the four-parameters model is applied to the sheep and cattle d18Odata sets. BQS 5 teeth from Bercy; KH: teeth from the Knap of Howar. R (Pearson): Pearson’s correlationcoefficient; r 5 cov (d18O, d18Om)/(s (d18O) * s (d18Om)); when | r | 5 1, the series are identical
Specimen X (mm) A (%) x0 (mm) M (%) x0/X r (Pearson)
BQS Bos1M3 41?8 1?5 18?1 25?3 0?43 0?98BQS Bos2M3 43?3 1?5 14?6 25?1 0?34 0?96BQS Bos3M3 39?4 0?9 4?6 25?8 0?12 0?94BQS Bos4M3 40?9 1?1 24?8 24?5 0?61 0?99BQS Bos5M3 31?0 0?7 17?8 25?4 0?57 0?95BQS Bos6M3 44?7 1?4 9?9 23?7 0?22 0?97BQS Bos7M3 57?3 2?1 26?9 24?1 0?47 0?99BQS Bos8M3 41?3 0?8 14?1 23?6 0?34 0?96BQS Bos9M3 43?0 1?0 26?8 24?0 0?62 0?94KH Bos1M3 37?6 1?2 17?0 25?1 0?45 0?98KH Bos2M3 39?6 1?3 21?5 24?9 0?54 0?99KH Bos3M3 46?8 1?1 26?4 25?1 0?57 0?98KH Bos4M3 42?1 1?3 22?0 25?5 0?52 0?99KH Bos5M3 34?2 0?7 19?2 25?2 0?56 0?98BQS Ovis1M2 33?4 1?7 6?2 25?8 0?19 0?98BQS Ovis2M2 22?8 2?0 7?6 23?8 0?33 0?99BQS Ovis3M2 29?2 2?1 12?5 23?5 0?43 0?98BQS Ovis4M2 19?2 1?1 7?2 24?3 0?38 0?96BQS Ovis5M2 36?7 2?8 7?9 25?1 0?21 0?99
Balasse et al. Birth seasonality and winter leaf foddering
38 Environmental Archaeology 2012 VOL 17 NO 1
Figure 6 Results from normalisation of the location in each cattle tooth crown where the highest d18O is measured (x0)
with the period (X) calculated for each tooth at Bercy (a) and the Knap of Howar (c). On graph b and d, on the
Y axis the period (1 5 a whole year) is divided into 12 units (months)
Figure 7 Results from normalisation of the location in each sheep tooth crown where the highest d18O is measured (x0)
with the period (X) calculated for each tooth at Bercy (a). Comparison with the Rousay sheep (b)
Balasse et al. Birth seasonality and winter leaf foddering
Environmental Archaeology 2012 VOL 17 NO 1 39
Kohn (2010), defined in tropical forests. Cor-
rected for the fossil fuel effect, this would lead to
an approximate value of 228?3 % in pre-industrial
ecosystems.
At Bercy, d13C values varying from 224?0% to
223?1% (n 5 6) were measured in aurochs bone
collagen (Balasse et al. 2000; Drucker et al. 2008)
corresponding to d13C values of 229?0 % to 228?1
% for diet. They were interpreted as reflecting feeding
in the understories of a dense forest. Fig. 8 compares
previous d13C values measured in bone collagen from
wild and domestic bovines (Balasse et al. 2000;
Drucker et al. 2008) with the range of intra-individual
variation of d13C values measured in cattle and sheep
tooth enamel (this study). To allow comparison, all
measured d13C values were translated to estimated
diet d13C values (see figure caption for an explana-
tion). For BQSBos1M3 to BQSBos9M3, the indivi-
dual mean d13C value measured in tooth enamel,
corresponding approximately to an annual mean
given that the sequence spans approximately a year,
falls within the range of variation of previous data
for domestic bovines from Bercy (reflecting a pluri-
annual mean). For BQSBos11M3 the mean d13C
value falls within the range of variation of previous
data for wild bovines, although only a short part of
the annual cycle is preserved in this tooth (Fig. 3).
When the range of intra-tooth variation is observed,
d13C values measured in BQSBos2, Bos5, Bos7 and
Bos8 fall seasonally within the range of variation
measured in aurochs, possibly reflecting feeding on
plants grown in similar ecological niches. From the
co-variation of d13C and d18O values in tooth enamel,
the lowest d13C values measured in the cattle M3
occur when d18O values are the lowest, in the winter.
The same pattern is observed in two sheep teeth
(BQSOvis2M2 and BQSOvis3M2). For both species,
seasonal consumption of plants from the neighbour-
ing oak forest (Leroyer 1998) can be envisaged.
Domestic stock could have been feeding directly in
the forest floor or lower part of the canopy as
mentioned for example in numerous accounts from
late Medieval and Renaissance Ireland (Lucas 1989),
or were provided with fodder collected in the forest
understories (see above).
Lynch et al. (2008) provided as an alternate
explanation for the lower d13C values measured in
aurochs from England compared with contempora-
neous domestic bovines, a preference for marshy
habitats for the aurochs. However, there is no evidence
for 13C-depletion in plants occurring naturally in
freshwater marshes and in the surroundings of rivers
and lakes (DeLaune 1986; Boutton 1991; Chmura and
Aharon 1995). Consequently, in the present state, the
canopy effect hypothesis is favoured.
In their stable isotope study of aurochs and early
cattle from southern Scandinavia, Noe-Nygaard et al.
(2005a and b) found no obvious evidence for leaf-
foddering in early domestic cattle (4000 to 3800
cal BC), with d13C values ranging from 222?5 to
221?4%, while d13C values of native aurochs from
the late Boreal–early Atlantic ranged from 224?2 to
Figure 8 Stable carbon isotope ratios (d13C) of the diet of cattle and sheep from Bercy, estimated from values measured
in tooth enamel (this study; mean and amplitude of variation) and in bone collagen: *BXXX were measured in
long bones (Drucker et al. 2008) and MB XXX were measured in mandibles (Balasse et al. 2000). The calculation
considered a 14?1% enrichment (e) between tooth enamel bioapatite and diet d13C (Cerling and Harris 1999) and
a 5% spacing between collagen and diet d13C. Shaded area: range of variation of d13C values estimated from
aurochs bone collagen d13C. B2201C, B6100C, B2001, B5500, B5600C and B6200C, were identified as aurochs
from morphological criteria (Drucker et al. 2008)
Balasse et al. Birth seasonality and winter leaf foddering
40 Environmental Archaeology 2012 VOL 17 NO 1
222?4%, reflecting a diet gathered in the dense
Atlantic forest. This comparison was based on bone
collagen values, reflecting pluri-annual means. At
Bercy, the annual mean estimated from the yearly
d13C sequences measured in the cattle M3 is
(213?4% in individuals seasonally feeding on low
d13C resources (Fig. 8). This would correspond to an
approximate value of 222?1% for collagen d13C
(using a 14?1% 13C-enrichment e between bioapatite
and diet, and a 5% spacing between collagen and diet
d13C). From this, it can be concluded that the
seasonal contribution of arboreal fodder to the diet
of early domestic cattle from southern Scandinavia
can not be definitely ruled out at least for three
individuals with collagen d13C values respectively of
222?26%, 222?16% and 222?44% (Noe-Nygaard
et al. 2005a, table 2). These estimations do not take
into account the precision around the determination
of the 214?1% enrichment between bioapatite and
diet (0?05%, Cerling and Harris 1999).
In temperate Europe, archaeological evidence of
tree foddering in the Middle Neolithic comes from
botanical remains found in sheepfolds or byres iden-
tified as such by ruminant dung layers and/or the
presence of shed deciduous teeth and high concentra-
tion of spheroliths. Research has focused on well-
preserved assemblages from lake shore settlements in
Switzerland (Akeret et al. 1999; Akeret and Jacomet
1997; Rasmussen 1989; 1993) and rockshelters from
southern France (Dehlon et al. 2088; Thiebault 2001;
2005). When all other pieces of evidence deal with the
foddering of caprines, at the Weier settlement in
Switzerland tree fodder was fed to cattle (Rasmussen
1989). Although most of the time the findings include
leaves or leaf bearing branches, the use of leafless
twigs was reported at Egolzwil 3 (Switzerland) asso-
ciated with small stock faeces (Rasmussen 1993).
Indeed, many descriptions from historical times attest
the harvesting of branches throughout the winter,
while deciduous trees are not bearing leaves, in
Scandinavia (Rasmussen 1993).
It may be important to note that the use of leafless
twigs as fodder might be more difficult to detect from
stable carbon isotopes. Although twigs are submitted
to the canopy effect as well as leaves, non-photo-
synthetic plant tissues in general, including twigs,
tend to be 13C-enriched by 1 to 3% compared with
leaves (Gebauer and Shulze 1991; Cernusak et al.
2009). Seasonal feeding on a diet gathered from the
forest understories would therefore be more difficult
to detect — compared with the feeding in open
pastures — if the consumed part is twigs rather than
leaves. For this reason the hypothesis of a leafy
resource should be favoured for the sheep and cattle
from Bercy.
Conclusion
Complementing pre-existing data from osteoarch-
aeology and bone collagen stable isotope analyses,
the present stable isotope study on tooth enamel
provides a more concrete picture of cattle and sheep
husbandry at Bercy, at the very beginning of the 4th
millennium BC. Sheep were lambing over a period
centred in the end April/beginning of May, only
slightly later than expected from what is observed
nowadays in temperate Europe at similar latitude.
Cattle were born over a period spanning approxi-
mately six months. This was unexpected compared
with a two to three months calving period in free-
ranging cattle populations. The extension of the calv-
ing period might have been related to the domestic
status of the herd, and possibly with seasonal food
supplementation. Some cattle and some sheep from
Bercy fed on a 13C-depleted resource in the winter,
potentially leafy fodder, although it is not possible
to say whether it was gathered in the forest by the
animals themselves, or harvested by the herders.
This practice did not happen every year and/or only
involved part of the herd. The effect on the timing
and duration of the reproduction cycle would be
less in sheep than in cattle, the breeding pattern of
the former being more directly linked to the pho-
toperiodic cycle. A direct consequence of an ex-
tended calving period would be on the annual
availability of cow milk, which would have covered
the whole year at Bercy. This is important informa-
tion in a context where the exploitation of milk by
the human community was demonstrated by the
presence of dairy product residues in ceramic vessels
(Regert 2007) and highly suspected from the demo-
graphic management of the cattle herd (Tresset
1996; 1997).
Acknowledgements
Yves Lanchon gave access to the faunal material for
stable isotope analysis. This research received finan-
cial support from the Region Ile de France, a CNRS
INSU program ECLIPSE II 2005–2007 (Climatic
constraints and development of Neolithic husbandry in
Western Europe at the Atlantic/Sub-Boreal boundary
(4th millennium BC), dir. M. Balasse and A. Tresset)
and a ERC Starting Grant GA 202881 SIANHE (dir.
M. Balasse). Stephanie Brehard provided us with her
expertise for the determination of sheep teeth. We
would like to thank Allowen Evin (UMR 7209
Balasse et al. Birth seasonality and winter leaf foddering
Environmental Archaeology 2012 VOL 17 NO 1 41
CNRS) and Gael Obein (Laboratoire Commun de
Metrologie, LNE-CNAM) for advice on the statis-
tical treatment of data.
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