**You dont have to store more water...** Just lose less water. Camels dont store water in their humps that just fat. They store water in an internal bladder. -Animals lose water either through general/unintended im gonna say osmosis but thats not quite right. With water being leeched from their skin from the dryer air. This happens most when we open our mouths -They lose water because of perspiration. We sweat to cool ourselves down. -They also lose water because of secretion. We gotta get rid of waste somehow. **All your creature has to do is not need to sweat, capture lost water from when opening its mouth (alot of hair maybe), and defecate dust.** Some animals evolve spines to capture moisture and draw it closer to their body for collection in desert environments. Saharan snakes are cold blooded so they dont need to sweat in the desert. They also burrow into the sand at noon to avoid to much heat.