How does specific heat capacity of water protect living organisms?
In many ways! One example is It enables a lot of body heat to be absorbed by sweat, which in turn helps cool the body.
Sweat is released by certain animals when the hypothalamus in the brain detects a raise in body temperature.
Vasodialation (widening) of capillary blood vessels allows blood to run closer to the surface of skin.
The sweat on the surface of the skin absorbs heat from the skin (and thus in turn from the blood). This energy transfer effectively removes heat energy from the blood and helps lower the body temperature of the animal. Due to the fact water has a high specific heat capacity, sweat can extract a lot of heat from blood and can therefore be highly efficient at lowering an animals core body temperature.
So efficient in fact that an old Inuit saying goes ‘if you sweat, you die’. This is because in cold climates, if you sweat (wearing wrong clothes, running a fever, etc) the sweat still removes heat from the body and that can lead to dangerously low internal body tempetatures.