Seasonal variations in hematological values and heart weight in two small mammals, a mouse: Apodemus sylvaticus, and a vole: Pitymys duodecimcostatus

Abstract

Hematological values and relative heart weight were analyzed in two rodents: the mouse, Apodemus sylvaticus (Linnaeus, 1758), and the vole, Pitymys duodecimcostatus (de Slys-Longchamps, 1839). The body weight of the two species was similar, 18.60 + 0.61 g for the mouse, versus 20.14 + 0.42 g for the vole. The specimens were captured in the same geographic area but in different ecological niches, since the vole is a burrowing animal, and the mouse is not. Hematological variations in both species were not related to age, sex, or gestation. P. duodecimcostatus had higher RBC count and Hb and He concentrations and lower MCV and MCH values than A. sylvaticus. However, MCHC values were almost the same in both species. The seasonal hematological variations observed in P. duodecimcostatus are like those found in most small mammals, while the hematological values found in A. sylvaticus barely changed throughout the year. The relative heart weight increased significantly in the two species during winter.