Giraffes exhibit an array of thermoregulatory mechanisms to maintain a relatively constant body temperature.
A giraffe's brain is cooled as it breathes through its nose. When a giraffe breathes out, the exhaled air has temperature substantially cooler than that of its body core. The cooling occurs by evaporation taking in the large nasal cavity which acts as a small refrigerator.
Their unusual body shape provides a large surface area. Easier to dissipate heat than retain it (a disadvantage in cooler weather).
Their long and slender, “dolicomorphic” (having a light build with relatively long body members) shape by increasing body surface area without proportionally increasing their metabolic mass enhances heat loss mechanisms.Their ossicones (horns) are well vascularized and may also function as a thermoregulatory organ.
They raise body temperature during the day, up to 40°C, to reduce water loss. In a very hot weather, the body temperature of a giraffe rises slowly during the heat of the day and falls again at night.
There was controversy over whether giraffe do or do not sweat. Mitchell and Skinner (2004) argue that giraffes do have sweat glands but opinion is divided as to whether they function.
Mitchell and Skinner maintain that sweat glands are scattered through the skin of giraffe but are more numerous, more dilated and more active under the patches, especially on the trunk where there are also more blood vessels.
When combined with the anatomy of the blood vessels supplying patches these data further support the idea that patches are thermal windows.