This whispering may have been caused by the settling grains of sand at Resonant Sand Gorge--the piles of sand sigh when you step on them, perhaps loudly enough to cause an already weary traveler to go in search of the demons calling him.
Today, there is no camel train to the east or west, just a set of trained camels ready to ride you in a circle out in the dunes for 40 or 60 RMB per person.
While not enough to go travel-mad, it's enough to get a taste for the rhythm of the two-humped camels and an ear for the singing sands.
It wasn't very easy to get there--we took a bus to a different destination but got off along the highway before it arrived, then paid a woman selling boiled ears of corn to let us pile in her minivan with her wares and drive us the remaining 2 kilometers to the park.
Once there, we rode Mongolia's oldest cable way across the gorge from arable land to arid sand, watched people sledding on the 300-meter dunes and admired the camels enough to take a short ride on them. That afternoon we went to the highway and flagged down a taxi to continue on. Baotou, Inner Mongolia's most populous city, was our next destination.