Physiology and morphology Bar-headed goose

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the main physiological challenge of bar-headed geese extracting oxygen hypoxic air , transporting aerobic muscle fibres in order sustain flight @ high altitudes. flight metabolically costly @ high-altitudes because birds need flap harder in thin air generate lift. studies have found bar-headed geese breathe more , efficiently under low oxygen conditions, serves increase oxygen uptake environment. haemoglobin of blood has higher affinity oxygen compared low-altitude geese, has been attributed single amino acid point mutation. mutation causes conformational shift in haemoglobin molecule low oxygen affinity form high oxygen affinity form. left-ventricle of heart, responsible pumping oxygenated blood body via systemic circulation, has more capillaries in bar-headed geese compared lowland birds, maintaining oxygenation of cardiac muscle cells , thereby cardiac output. compared lowland birds, mitochondria (the main site of oxygen consumption) in flight muscle of bar-headed geese closer sarcolemma, decreasing intracellular diffusion distance of oxygen capillaries mitochondria.

bar-headed geese have larger wing area weight other geese, believed them fly @ high altitudes. while decreases power output required flight in thin air, birds @ high-altitude still need flap harder lowland birds.