Meet Macho and Feminina, the two mules who here are ferrying our packs up the first and steepest pass of the six-day Illampu Circuit.

Their names mean "male" and "female" because the Bolivians don't go in for anthropomorphising animals as we sentimental Westerners do. However, as I observed on several occasions, you rarely see one mule on its own, and the Bolivians make a point of keeping friends and relatives together. These two are buddies and apparently only work dejectedly at half-capacity when on their own.

Mules get altitude sickness just as we do, the unacclimatized ones fall over and die, just like us, and they get all hot, sweaty and smelly, just like us. You gotta love 'em.