ABSTRACT
The aim of this study was to compare some physiological parameters in three species of snakes [Psammophis schokari aegyptius [from Aswan], Psammophis schokari schokari [from Al-Wahat] and Psammophis sibilans sibilans [from Mansoura]] during the winter. Physiological parameters including thyroid hormones [T3 and T4], thyroid stimulating hormone [TSH], insulin hormone, calcium, iron, sodium, potassium and cholesterol, were recorded in the three species of the snakes. The results showed that serum TSH, T4, insulin hormones and iron were lower in the serum of Psammophis schokari aegyptius than the other two species. Conversely, all other parameters, i.e. T3, Na, K and calcium increased significantly in the serum of Psammophis schokari aegyptius than in the other species. On the other hand, a higher level of cholesterol was found in the serum of Psammophis schokari schokari than that in the other two species. Level of cholesterol in the serum of Psammophis sibilans sibilans was lower than the other two species