Heuvelmans was born on 10 October 1916 in Le Havre, France, and raised in Belgium and earned a doctorate in zoology from the Free University of Brussels (now split into the Université Libre de Bruxelles and the Vrije Universiteit Brussel). Heuvelmans was a pupil of Serge Frechkop, a proponent of the Theory of Initial Bipedalism. In 1939, his doctoral dissertation concerned the teeth of the aardvark. During World War II he had escaped from a Nazi prison camp and later worked as a jazz singer in Paris.