Aspinall's whole life was dangerous and controversial, and in the popular press there was much speculation that he had aided the disappearance of his gambling crony Lord Lucan. But by far the most important part of his career was his work with animals. He insisted on treating them not as beasts to be exhibited, but as friends to be pampered. He ensured that they should have adequate space to live in the same kind of groupings as in the wild, and took the greatest trouble to reproduce the variety of their natural diet.
His gorillas, for example, were given all kinds of berries, and treats such as roast meat on Sundays and chocolate bars.