I was on a trekking holiday in the Himalayas. Because there are no roads, goods have to be carried either on porters鈥� backs or by pony trains. The tracks are steep, often consisting of uneven steps. The ponies need to keep looking at the track immediately ahead in order to position their front hooves. But how do they know where to place their hind hooves?
Bob Miles, Sidmouth, Devon, UK