Blood gases, air cell-blood gas differences, blood pH, and hematology
were compared in embryonic coots (Fulica americana peruviana) at 4150
m and sea level in Peru. Neither arterialized nor venous O2 tensions d
iffered significantly between montane and lowland groups but blood CO2
tensions of the two groups differed significantly. The air cell P(O2)
-arterialized blood P(O2) difference of montane eggs was less than hal
f the value in lowland eggs. Both arterialized and venous CO2 tensions
differed substantially between montane and lowland groups. Despite th
ese differences, plasma pH at both altitudes was statistically indisti
nguishable, due in part to variation in plasma [HCO3-]. Hematocrits of
montane embryos were significantly higher than that of their lowland
counterparts.