Revista Chilena de Historia Natural 80 (3): 275-284, 2007
RESEARCH ARTICLE
Pulmonary hematological parameters, energetic flight demands and their correlation with
oxygen diffusion capacity in the lungs
Hematological parameters of birds and mammals seem to respond to environmental
requirements, such as hypoxia at high altitude and the energetic demands of locomotion and flight. In this work we hypothesize that
lung capillary hematocrit and red blood size may be influenced by the energetic requirements of flight. Also, we propose that
hematological parameters should vary together with the morphological parameters that determine oxygen diffusion capacity. We
analyzed the red blood cell size and the local characteristics of the pulmonary capillary hematocrit correlating these with the pulmonary
factors that determines the oxygen diffusion capacity. We deal with seven species, non- flying and flying birds and mammals, with
different energetic requirements. The capillary hematocrit was not different in each taxon, but the red blood cell size was smaller in
flying mammals and birds than non-flying ones. Correlation of erythrocyte size with the diffusing characteristics of the lungs produced a
non-phylogenetic clustering with a group constituting by the bats Tadarida brasiliensis y Myotis chiloensis,
and the bird Z. auriculata; revealing similar functional response in unrelated species. Finally, in mammals, a negative
correlation between the red blood cell size and the mass-specific oxygen diffusion capacity was obtained. These results suggest that
the direction of the hematological and pulmonary adjustments is governed mainly by the requirements of flight independent of
phylogenetic origin of the species studied.
Key words:
cost of flight, capillary
hematocrit, red blood cell size, oxygen diffusion capacity
