In the winter, they are more of a smoky gray ... by excreting dry feces and concentrated urine. These remarkable desert ...

In winter, even desert plants may hold enough moisture to ... for approximately 3,500 years and have been long valued as pack animals. They can carry large loads for up to 25 miles a day.

Winter months are cooler with temperatures ... Cacti have spikes on their steams and leaves to stop them being eaten by animals. The desert iguana changes colour to regulate body temperature.