The rhinoceros constitutes a rare surviving example of megafauna, and grows in adulthood into an extraordinarly fast and powerful animal, dangerous enough when hunted to win a place in the African Big Five.

About a decade ago, I was living in Lincoln Park in Chicago, across the street from the zoo, which I was consequently able to frequent. One day, I was flabbergasted to see a zoo-keeper delivering a back-rub with a bristle push broom to a full-grown white rhinoceros, who was visibly ecstatic. One could see that this practice was a regular routine.

In fact, I found that the rhino would come trotting over expectantly, when out-of-doors in its sunken enclosure, if any human approached invitingly close to the fence. That friendly rhino was obviously hoping that someone else might volunteer to scratch her back.

Photo taken seconds before it charged.

Telegraph