"Finally, our research shows that nutritionally-balanced food sources that are used extensively by a wild population may need special attention in terms of 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."
Dr Felton and her colleagues found that the monkeys ate a wide variety of fruit and vegetables 105 different plants belonging to 63 species during the 12 months of observation. Figs were particularly popular. The monkeys rarely ate insects, which are rich in protein.
The spider monkeys did not specifically select either the most energy-rich or the most protein-rich foods that were available, and the daily amount of food they ate varied quite widely, averaging about 1 kg a day, but sometimes as much as 2.4 kg a day. However, they maintained their daily protein intake around 0.2 MJ (11 grams), whereas their intake of carbohydrates and fats varied between 0.7-6.2 MJ. The availability of sweet, ripe fruit was significantly related to the variation in their daily energy intake the more there was, the more they ate.
"To maintain a stable intake of protein, spider monkeys consumed large amounts of carbohydrates and fats when protein content in the food was low, for instance when their diet consisted entirely of ripe fruit, and consumed far fewer carbohydrates and fats when feeding on items rich in protein," said Dr Felton.
|Contact: Emma Mason|
Oxford University Press