Monkeys control their obesity without supplements WOW, how do they do it?
The Australian National University
ANU News
New research from The Australian National University shows that wild spider monkeys control their daily protein intake in a similar way to humans, suggesting that the human susceptibility to obesity might have much earlier evolutionary origins than previously thought.
Dr Annika Felton, a Departmental Visitor at the Fenner School of Environment and Society at ANU, spent a year in the Bolivian rainforest following 15 Peruvian spider monkeys, observing the dietary habits of individual monkeys from dawn to dusk.
“We found that the pattern of nutrient intake by wild spider monkeys, which are primarily fruit eaters, was almost identical to humans, who are omnivores,” Dr Felton said. “Spider monkeys appeared to aim for a target amount of protein each day, regardless of whether they only ate ripe fruit or mixed in other vegetable matter as well. This result was unexpected because, previously, ripe fruit specialists were thought to be ‘energy maximisers’. In other words, they would aim to maximise their daily energy intake. Our findings show this is not the case.”
Dr Felton said that the consequence of tight protein regulation is the same for monkeys and humans: if the diet is poor in protein but rich in carbohydrates and fats (energy dense food) then individuals will end up ingesting a great deal of energy in order to obtain their protein target, which can lead to weight gain. This ‘protein leverage effect’ is thought to play a significant role in the human obesity problem found in modern western societies. “Our results suggest that an adjustment of the nutritional balance of diets as a means to manage human obesity might similarly be an option for mitigating obesity in captive primates,” Dr Felton said.
“Our findings are also interesting from an evolutionary point of view. Similarity in the regulatory pattern of protein intake between distantly related species, such as humans and spider monkeys, possessing very different dietary habits, may indicate that the evolutionary origins of such regulatory patterns are quite old, potentially far older than the Palaeolithic era [2.5mya – 10,000ya]. If we are not dealing with convergent evolution here – in other words that spider monkeys and humans have evolved this trait independently – then this trait may have been shared by our common ancestor.
“Finally, our research shows that nutritionally-balanced food sources that are used extensively by a wild population may need special attention in conservation planning, perhaps by regulating logging and selecting certain tree species for re-planting. The majority of the monkeys’ nourishment was sourced from a species of fig tree, Ficus boliviana, that is currently being harvested for timber in Bolivia.”
The research, published online today (Wednesday 20 May) in the journal Behavioral Ecology, is available at: http://www.oxfordjournals.org/our_journals...epdf/arp021.pdf
Dr Felton is currently based in Sweden and is available for interview.
Media contact: Simon Couper, ANU Media Office 02 6125 4171, 0416 249 241
Filed under: Media Release, ANU College of Medicine Biology and Environment, Science
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