In the original Dutch version writer Anton Koolhaas, who also wrote the script, provided the voice-over.

Haanstra had already shown interest in human and animal behaviour in his previous films, like Zoo (1961).

In preparation for this documentary Haanstra and his camera crew traveled across the world for three years.

They filmed animals and people in many different continents (Africa and Antarctica get extensive attention), while the well known Dutch ethnologist Gerard Baerendts was consulted for scientific advice.

Haanstra would later make two other documentaries about animals: Nationale parken... noodzaak (1978) and Chimps onder elkaar (1984).