User:SparrowGrrl/Arabian oryx

Adaptations for desert environments
The Arabian oryx changes its physiology and behavior at different times of the year to increase survival during times when food and water are in limited supply. During the summer, when droughts are common in the desert environments where it lives, the Arabian oryx will drastically reduce its minimal fasting metabolic rate by lying completely inactive beneath shade trees during the day and ranging over smaller areas at night to forage. By letting its body temperature rise during the heat of the day, it uses less evaporative cooling and retains more body water, and at night, the cool night air lowers its temperature back to the normal range. The oryx’s arterial blood temperature is partly lowered by a network of small arterial vessels with a large surface area called the rete mirabile, which branches from the two carotid arteries to the brain and allows for heat exchange between warm arterial blood and the cooler blood in the sinus cavities. Because of these changes in behavior and physiology, it was shown that Arabian oryx can reduce their urine volume, fecal water loss, and resting metabolic rate by at least 50%, demonstrating how efficient these animals are at surviving in times when water and food are scarce.

New research shows that the Arabian oryx has more blood volume than similar sized non-desert mammals.