Going Ape! 1981

When his father - who owned a circus - dies, Oscar inherits 5 million dollars - and 3 orangutans. However there's a condition connected to the money: if he gives away the apes or just one gets sick or dies during the next 3 years, the zoologic society will get all the money. So he not only has to deal with 3 apes and an annoyed girlfriend, but also with a greedy zoologic society's president.