D: Whew! I'm thirsty Yaël, would you pass that pitcher of water?
Y: It is warm in here today, Don---luckily we've got plenty to drink.
D: I've always wondered about animals living in the desert--- Why aren't they thirsty all the time?
Y: Most desert organisms have special adaptations to keep them hydrated. For example, some can extract any water they need from their food, and don't drink at all. Others minimize water loss by concentrating their urine and feces, or by reducing evaporation through their skin and respiration.
D: Ooh! That reminds me! I did read about a bizarre adaptation in some lizards that lets them drink through their skin!
Y: Drink through their skin? That is bizarre!
D: Scientists suspected for some time that these lizards were taking up water through their skin.
Initially, they thought the lizards were absorbing water directly through their skin, like some amphibians, do. But unlike the moist skin of amphibians, dry scaly reptile skin keeps precious water in and out!
The researchers had also noticed that when the lizards got wet, they would raise their bodies and lower their heads. Perhaps the lizards were somehow using gravity to channel the water down toward their mouths? This prompted the researchers to examine the skin and scales of the lizards in detail, using high-powered microscopes. They found that two species, Australian thorny devils and the Texas horned lizards, have networks of tiny tube-like channels under their scales, covering their entire body. The tubes funnel water across the body and into the corners of the lizard's mouth, where it's swallowed.
Y: Like covering your body with straws!
D: [CHUCKLES] Almost. The discovery solved one mystery about how desert reptiles get enough water.
