Human interactions with chimpanzees are exceptionally inadvisable in the first place. The primates have immensely greater strength than a human, and sharp teeth that have proven capable of completely disfiguring, as well as killing, humans (via Live Science). Per observations of their behavior in the wild, chimpanzees have displayed exceptionally human-like capacities for war, factionalism, and even sadism. Observations of the 1970s Gombe war between rival chimpanzee groups in particular forever changed contemporary notions of them as completely passive and friendly (via Slate).
In 1951 this knowledge was not yet widely known, and even though Peggy was a juvenile, Reagan learned of her species’ strength the hard way. While on set, she became fixated on Reagan’s necktie and began to pull on it. This act tightened the knot, rapidly restricting the actor’s airway until he eventually managed to get away from her and had the tie quickly cut from his neck (via Mental Floss). After the film’s premiere to a public and critical reception that was lukewarm to negative, and possibly also because of this brush with death, Reagan dismissed the notion of appearing in future Bonzo films.