The Sperling's famliy commitment to conservation was inspired by Delheim's founder Hans Hoheisen.

" The Hoheisen name is synonymous with one of the biggest land donations ever in the history of WWF South Africa. In 1990 Mr Hans Hoheisen donated 13 833 ha on the Kruger National Park’s western border to WWF. It was on part of this land that the Southern African Wildlife College was later constructed to train protected area managers from Africa for Africa." - WWF South Africa Annual Review 2005