In the sixties, Wim Mager, a photographer from Rotterdam, had two tamarins. At the time it was legal to buy monkeys at a pet shop. What started as a hobby, ended in a primate park. Mager decided to give up his job as a photographer and developed the ‘apen-heul’ concept (‘apen’ means ‘apes’ or ‘monkeys’ and ‘heul’ is old-Dutch for ‘refuge’ or ‘safet zone’).

The concept was simple: people enjoy primates most when the primates are enjoying themselves and behaving naturally. So the monkeys no longer lived in cages with bars, but in large, natural enclosures in the forest.