JUNKIE MONKEYS

Cape Town’s baboon raiders hooked on sugar

● Cape Town’s famously hungry baboons may be harming their health by pilfering high-calorie human food.

Baboons from the Cape Peninsula are heavier and have worse teeth than a group from the Eastern Cape, and show early signs of future diabetes, a new study has found.

The findings were based on post-mortem tissue samples from 17 Cape Town baboons euthanased to stop them raiding urban areas for food.

The samples were compared with others from baboons which live near the Karoo town of Pearston, in the Eastern Cape, with no known history of raiding.

Physical differences between the groups, while relatively minor, add further weight to the theory that baboons that prefer human food over veld foraging are putting their physical wellbeing at risk.

“Speculatively, if the peninsula baboons continue to gorge on these sugary [human] foods, they may suffer from the same fate as many of their human cousins who develop diabetes, blood pressure issues and even blindness,” said study lead author Tertius Kohn, from the medical bioscience department at the University of the Western Cape.

“None of the baboons [in the study] were that advanced, but the warning signs are there, albeit microscopic.”

Based on previous research on the impact of human food on baboons — notably in Kenya, where baboons feed from dumps — the research team hypothesised that Cape Town’s raiding baboons might exhibit the same physical flaws, notably signs of insulin resistance. Their findings appear to confirm exactly that.

Insulin is a hormone that allows the body to efficiently convert carbohydrates and maintain normal blood sugar levels. Resistance to insulin in baboons could therefore lead to elevated blood sugar levels and the same lifestyle diseases common in humans, including obesity and cardiovascular disease.

Analysis of thigh muscle samples showed many of the peninsula animals had fewer working insulin receptors than the Pearston group, meaning they would be less able to lower their blood sugar levels after eating and were potentially becoming more insulin-resistant.

The Cape Town baboons were also heavier than the Eastern Cape group — an average of 32kg vs 29kg — and had worse teeth

“Of the 12 baboons in the peninsula troop for which photographs were available, 50% showed some form of teeth decay, whereas only one [of the seven Eastern Cape baboons] showed slightly worn teeth,” the researchers said.

“The Cape Town baboons’ dental problems range from missing teeth and broken fangs to general wearing down.”

Justin O’Riain, director of wildlife research at the University of Cape Town’s Institute for Communities and Wildlife in Africa, said results suggest the peninsula baboons are more sedentary than wilder troops and showed metabolic indicators “along the path that leads to diabetes”.

The findings also support the view that overlaps between human and baboon habitats, particularly waste sites, need to be controlled. “From Saudi Arabia to South Africa, baboons may visit waste sites on a daily basis,” said O’Riain.

“This kind of research should be conducted on these troops that have almost unlimited access to human foods and consequently do little more than stroll to and from their sleeping site to the dump on a daily basis.

“Current management, which seeks to reduce the spatial overlap between baboons and urban areas, has worked well over the previous decade, with some troops kept out of town for up to 98% of the time. So this study has measured the worst offenders and we think the majority of the population will be healthier on their diet of fynbos.”

The latest study, published this week in the journal Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, was funded partly by the National Research Foundation and was peer-reviewed by international experts on primate health.

Sports science professor Tim Noakes, who has flagged the link between the Western human diet and insulin resistance, said he was not surprised by the findings. “We (humans and baboons) evolved from a common ancestor with the other primates. Baboons have had very little exposure to sugar. They cope very poorly with high carbohydrate load, just as humans do,” he said.

O’Riain said the finding “dovetails well with what Tim Noakes always said, that metabolic indicators can reveal that you need to adjust your lifestyle and diet before the onset of the disease”.

Marian Nieuwoudt, Cape Town’s mayoral committee member responsible for environmental matters, said baboon monitors had a 99% success rate at keeping the animals out of urban areas. “We thus believe that the baboon management programme assists in better overall troop health.”