The deer mouse has a very large area where it found and
survives. It could be found below sea level in California to as high as 4,300m
in Alpine conditions. The higher the mouse goes the less oxygen there is. So in
order to adapt to life at high altitudes the mouse’s body must change. When the
air becomes thin and oxygen is low the protein in the deer mouse’s haemoglobin changes.
Instead of having 1 strand of protein they would have six. This then makes
chemical changes to the haemoglobin in the red blood cells which allows it to
bond with a lot more oxygen. This means that the red blood cells in blood can
carry a lot more oxygen to the mouse’s body. This is an adaptation that the
mouse has evolved to have.