Research finds honey is a sweet treat for chimps during food droughts

Thursday, 06 August 2015

Chimpanzee

New research by an Oxford Brookes academic has found that wild chimpanzees eat honey from wild beehives as a ‘fallback food’ during lean months when forest fruit is in short supply.

Chimpanzees observed in Bulindi, Uganda, over a period of 22 months, were also found to make stick tools to help them retrieve the highly nutritious food source.

Dr Matthew McLennan from the Department of Social Sciences at Oxford Brookes recorded the eating habits of chimpanzees between 2007 and 2014 and found that the chimps were using sticks to dig-out underground bee nests to get to the honey and larvae.

In human foraging societies, honey can make up a substantial portion of the diet during ‘honey seasons’ and people can devote hours every day to procuring honey. By contrast, honey is only an occasional food item for chimps and the amount eaten is overall, small. Dr Matthew McLennan, Oxford Brookes University

Regular diets of chimps are mostly composed of fruit but they occasionally eat insects and insect products like honey; however, it wasn’t clear if the chimps were simply eating honey when it was most available or if they exploited this resource during times of food scarcity.

The research found that honey-feeding by the chimps was unrelated to peaks in flowering, when a diverse range of nectar and honey sources are available to bees and when local people harvest beehives. Instead, the chimps ate more honey when less fruit was available and when they ate less fruit overall.

Honey is rich in carbohydrate sugars and therefore it is not surprising that many wild animals like to eat it. Dr Matthew McLennan said: “The problem facing any would-be honey hunter is how to overcome the bees’ defences to gain access to the stores of nutritious honey.

“African honey bees are notorious for defending their nest through aggressive stinging – the stings are too painful for most animals to withstand for long. Smaller, sting-less bees fortify their nests with thick walls of mud and wax or by building their nests up to one meter underground, making them extremely difficult to access.

“Chimpanzees have found a way around this problem by using stick tools to overcome the bees’ defences, for example to break open or dig out a nest.” chimpanzee-stick-tools Because chimps are our closest living relatives, it seems certain that honey was a regular food for ancestral humans, including Australopithecus and early Homo lineages, who probably also used tools to access it.

Matthew continues: “There’s a fundamental difference between honey use by chimps and people. “In human foraging societies, honey can make up a substantial portion of the diet during ‘honey seasons’ and people can devote hours every day to procuring honey. By contrast, honey is only an occasional food item for chimps and the amount eaten is overall, small.”

Honey therefore best qualifies as a nutritious sweet treat for chimpanzees – but one that provides a welcome energy boost during lean times. With the development of more sophisticated tools during the course of human evolution, as well as the use of smoke to subdue the stinging bees, people were able to exploit honey more efficiently and in much larger quantities, than is possible for chimps.

Like many populations of great apes, the Bulindi chimpanzees live in an environment increasingly impacted by human activities. Over the course of a decade more than 80 per cent of their forest home has been cut down for farming. Matthew hopes that by researching the lives of these chimpanzees, and drawing attention to their plight, solutions can be found to enable these fascinating beings to coexist with their human relatives.

Image credit: Matthew McLennan