Does altitudinal difference modulate the respiratory properties in subterranean rodents' (Cryptomys hottentotus mahali) blood?

Do burrowing mammals that naturally experience hypoxic and hypercapnic conditions exhibit modifications to the blood chemistry at high altitudes? We investigated two populations of the Lesotho mole-rat living at different altitudes in the highlands of the Drakensberg. There was no significant difference between the specimens from 3200 and 1600 m in mean red blood cell count (RCC = 8.9 × 106 ± 1.6 × 106 vs. 8.4 × 106 ± 0.95 × 106 mm3, respectively) or packed red cell volumes (haematocrit = 0.51 ± 0.06 vs. 0.49 ± 0.05, respectively). However, blood haemoglobin (Hb) concentration was significantly higher in the high altitude than in the low-altitude specimens (178 ± 9 vs. 160 ± 16 g/l). The oxygen equilibrium curves of thawed whole blood showed no displacement to the left in the animals sampled at the higher elevation. The data indicate that the oxygen-transporting properties of mole-rat blood do not change markedly with increased elevation and that burrowing mammals are a priori hypoxia-adapted.