How do gazelles survive during food and water shortage for a prolonged period of time in the desert? By shrinking their liver and heart, of course! Sand gazelles' livers and hearts--which are important determinants of metabolic rate--decrease significantly in mass during four months of food and water restriction. Conversely, the gut walls, which are responsible in ruminants for 28–46% of whole-body protein synthesis, an energy demanding process, did not decrease significantly in mass. There are few sources of drinking water in the desert, so sand gazelles must rely on vegetation for both food and water requirements. |