## 3 Results and Discussion
### Isotopic Analysis in Modern Mammals
#### 3.2.2 \(\delta^{34}\)S Values of Various Mammals
The concurrent difference in these isotopes suggests divergence in the day-to-day raising methodology applied in animal husbandry (such as care production, nutrition, breeding, mobility, or grazing on different lands). This disparity in livestock practices is supported by the distinct sulfur isotopic values found in the various environments. In theory, there should be differences in the \(\delta^{34}\)S values of animals feeding predominantly on resources coming from different geological areas (e.g., plains near the city or mountains or resources coming from other countries). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Species** & **Age** & \(\delta^{34}\)**S,** & **sd** & **Authors** \\ \hline All herbivores mammal samples & Recent & 7.50 & 1.47 & This work \\ \hline All herbivores mammal samples & Old, from Greece & 12.45 & 4.53 & (72,73) \\ \hline All herbivores mammal samples & Classical site, Thebes & 13.30 & 2.18 & (73) \\ \hline All herbivores mammal samples & Early Iron Age, Thessaly & 7.90 & 2.50 & (80) \\ \hline All herbivores mammal samples & Minoan, Chamalevi & 17.7 & 1.72 & (80) \\ \hline Cattle, from Crete & Minoan, Chamalevi & 18.20 & & (80) \\ \hline All herbivores mammal samples & Earl Minoan to Roman, Crete & 11.60 & 2,45 & \\ \hline Sheep, Ovi varies & Middle to Late Minoan, Chamalevi & 12.60 & 2.72 & (81) \\ \hline Sheep, Ovi varies & Middle Minoan, Apodoulou & 10.40 & 0.63 & \\ \hline Cattle, from Crete & Recent & 9.60 & 2.16 & This work \\ \hline \hline \end{tabular}
\end{table} 
Table 5: \(\delta^{34}\)S of recent and archaeological mammals. However, the above analysis model is not valid when Chalkidiki is compared to the Sparta area: elevated sulfur isotopic values are observed from North to South while nitrogen values are reduced (Figure 9). Furthermore, sulfur enrichment between the north and south is observed, even when we compare plants and mammals (Figure 10). Nevertheless, the mammals that originate from the Sparta area always demonstrate an increase in sulfur isotopic values following a decrease in nitrogen values from north to south. According to [PERSON] and [PERSON] [48], rainfall affects nitrogen isotopic values (the slope of the variation in \(\delta^{15}\)N with precipitation is equal to 0.38/100 mm for both Greek plants and herbivores). The isotopic results show that the lower nitrogen isotopic values in Sparta compared to those in Chalkidiki are due to higher rainfall in the former. The average rainfall at the A. Dimitriou and Elo stations (Sparta area) over the last 22 years was 650 mm and 505 mm, respectively. On the other hand, the average rainfall at the A. Prodromos and Arnaia stations (Chalkidiki peninsula) over the last 35 years was 420 mm and 440 mm, respectively (Impact Investigation of variable rainfall in areas of the Greek territory, NTUA [87]). This indicates that the climate (rainfall) affects the values of the isotopes. The average sulfur levels in pigs are higher than those in herbivores, which can be attributed to their omnivorous diets. However, the \(\delta^{15}\)N values of pigs (Table 2) do not align with those typically associated with a mixed diet [88]. [PERSON] et al. [88] demonstrated a strong linear relationship between \(\delta^{15}\)N values in all tissues and the amount of marine protein consumed. When (at least) 25% of the dietary protein has a marine origin, then the \(\delta^{15}\)N values start to increase consistently among individuals consuming the same diet [89]. Additionally, adolescent pigs consistently showed lower \(\delta^{15}\)N values compared to piglets or sows consuming the same diet [88]. The observed high carbon values indicate minimal contributions from C4 plants in their diet (Table 2). In conclusion, higher \(\delta^{34}\)S values may indicate a small proportion of marine protein, such as fishmeal, in the diet or could result in the consumption of vegetation enriched in marine-derived sulfur. This suggests, in this case, that the studied pigs likely grew up closer to the coast.