In 1972, Haanstra released another feature length documentary, the outstanding Ape and Super Ape. The culmination of his interest in the behaviour of humans and animals, ultimately became Haanstra's personal favourite. Haanstra studied many different animals in their natural environment, recording their behaviour aggression, territorial instincts, hierarchies and mating habits in scenes that have seldom been equalled on film. Despite the obvious parallels with human behaviour and responses, Haanstra never laboured the point, nor did he ever settle for an easy laugh at the expense of either species. It took three years of hard work to make this film. Haanstra's team travelled to the most far off corners of the world, covering more than 175,000 kilometres. Haanstra returned with 40,000 metres of film to be edited into a 2,825 metre film. While preparing the film Haanstra lived like a hermit, studying dozens of books on the subject. He also received invaluable advice from the distinguished ethologist Professor Gerard Baerends. "My biggest concern was to ensure that Ape and Super Ape would appeal to a wide audience and not just a few biologists. It took a lot of effort to find the right form and style. I decided to make my point at the very beginning of the film, which is essentially about the preservation of all species. I also pointed out the most obvious differences. The physical differences between the species aren't that big. Human beings might even be slightly inferior in some ways. But our advantage is our intellect and the fact that we can use our hands. We used to be quadrupeds until we learned to walk upright. And we can teach what we learn to future generations. Other species can't do that. It has been said that people become aggressive through circumstances, but I have now learned that both animals and human beings are aggressive by nature! Everything evolves around retreat and attack. I have seen this with my own eyes and recorded it. It's about the survival of the fittest in its ultimate and most ruthless form." Ape and Super Ape has various dimensions. It is beautiful, moving, humorous but, above all, remorseless.