What are you supposed to feed a monkey?

If you answered bananas, you are wrong.

That is, according to Paignton Zoo in Devon, U.K., where zookeepers have banned their monkeys from having bananas.

Wild monkeys do eat bananas, but the bananas that monkeys are fed in zoos are cultivated for humans to have more sugar. These bananas are just too sweet for primates. Head of Conservation and Advocacy at the Paignton Zoo, Dr. Amy Plowman, says that giving the bananas to monkeys is like feeding them cake or chocolate.

"Compared to the food they would eat in the wild, bananas are much more energy dense — they have lots of calories — and contain much more sugar that’s bad for their teeth and can lead to diabetes and similar conditions," Dr. Plowman said in a statement on the zoo's website. "It can also cause gastrointestinal problems as their stomachs are mostly adapted to eating fibrous foods with very low digestibility."

The monkeys have now been weened off bananas and other fruit, and are instead being served green leafy vegetables and lots leafy branches, called browse. The monkeys are only fed bananas when they need to take medication, which is hidden inside the fruit.

The European Association of Zoos and Aquaria, a body that advises zoos on animal diet, also supports the vegetable-heavy diet. The organization found that while primates do eat bananas and other fruits in the wild, the "fruits consumed by wild primates are more comparable in their nutrient composition to vegetables used in zoos."

This doesn't mean that monkeys don't like bananas. Like children who love cake and chocolate, studies show that primates will choose sweet fruit over others.

In one experiment from 1936, a number of monkeys from different species were given a variety of foods and their reactions recorded. The resulting paper, titled "Some Problems Regarding The Feeding Behavior Of Monkeys," found the primates were pretty much unanimous in their preferences: (1) Grape, (2) Banana, (3) Apple, (4) Carrot, (5) Lettuce or Cabbage, (6) Nuts, (7) Bread.