Bananas deemed "too unhealthy" for monkeys
If you've made a New Year's resolution to diet after your festive blow-out, here's a tip from a bunch of monkeys – avoid the bananas.
Animals at Paignton Zoo Environmental Park in Devon have been on a health kick for some time. The reason? Food grown for people is just too sweet and sugary for them.
And top of the hit list is bananas.
"People usually try to improve their diet by eating more fruit – but fruit cultivated for humans is much higher in sugar and much lower in protein and fibre than most wild fruit because we like our fruit to be so sweet and juicy," said Dr Amy Plowman, Head of Conservation and Advocacy and animal nutrition expert. "Giving this fruit to animals is equivalent to giving them cake and chocolate," she said.
To most people, monkeys and bananas go together like a horse and carriage, but it seems that this cliché is now redundant.
"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. "It can also cause gastrointestinal problems as their stomachs are mostly adapted to eating fibrous foods with very low digestibility," she said.
This is not a New Year fad, but an ongoing programme to adjust diets. And it's not that the animals in the Zoo have been eating badly – research is constantly helping animal staff to do the best for the animals in their care.
Has it been hard to wean animals off fruit?
"We reduced the amounts slowly so they had a long period to get accustomed to their new diet," Dr Plowman said. "They didn't get a choice but – unlike children – they couldn't complain," she said.
"The alternative is vegetables and lots of them, especially leafy green veg," Dr Plowman said. "We still use starchy root veg. but have reduced amounts as it can still be quite high in sugar and other readily-digestible carbohydrate. Leafy green veg is great because it is high in protein, fibre and lots of vitamins and minerals," she said.
A typical monkey diet now features lots of green leafy vegetables, smaller amounts of other vegetables and as much browse – leafy branches – as possible, especially for the leaf-eating monkeys. A specialist pellet feed gives them the correct balance of nutrients, while small amounts of cooked brown rice can be scattered around enclosures to encourage foraging.
However, animals do still get banana if they are unwell and the keepers need to make sure they take medication.
"Putting it in a piece of banana works really well, as it's such a treat now," Dr Plowman said.
Most animals in the wild spend most of their active time searching for food. This food generally has low energy, high fibre and very low sugar and is hard to digest. So wild animals use up lots of energy acquiring and consuming food and avoiding predators while they do so.
In the Zoo, as in most developed human societies, food is very easy to obtain, there are no predators to avoid while foraging and so procuring and processing food requires very little energy. Keepers combat this with what is called environmental enrichment – food is scattered, hidden, given whole instead of chopped or placed in puzzle feeders to get the animals to work for their food.
"Food meant for humans is usually much more energy dense than wild food and is easily digestible," Dr Plowman said. "So it's possible for Zoo animals to use virtually no energy in acquiring and processing very energy rich food. This could give rise to the sort of issues we see in most Western human societies, like obesity, diabetes, heart disease – conditions that are virtually unheard of in the wild," she said.
The good news is, Paignton Zoo's fruit-free diet is bringing improvements in physical health and changes in some behaviours.
"We have noticed an improvement in the condition of primate coats – in particular the colour and thickness of the fur of the Sulawesi crested black macaques," said Matthew Webb, Senior Head Keeper of Mammals. "Smaller monkeys such as tamarins and marmosets are highly strung animals and live in tight-knit social groups which can be quite aggressive at times. Reducing the sugar in their diets has calmed them down and made their groups more settled," he said.
