Large Multi-Species Primate Study Shows Diversity In Eating Habits

Lee Rannals for redOrbit.com – Your Universe Online

Some monkeys consume their five-meals-a-day within just an hour, according to a new in-depth analysis of primate eating habits.

Researchers at the University of East Anglia (UEA) have conducted the most thorough analysis of primate eating habits and their findings have been published in the journal Oikos. The team compiled data from 290 primate dietary studies spanning 42 years of research across 17 countries, focusing on the amount and diversity of fruit consumed by primates in neotropical forests of South and Central America.

The team revealed how primate body mass and the amount of fruit consumed are linked. The study shows how small monkeys like marmosets and tamarins eat more insects and less fruit, while other monkey species can consume as many as 50 portions of fruit in a single day.

According to the findings, the amount of fruit eaten gradually increases with greater body size and peaks at medium-sized primates like saki monkeys. However, fruit intake then declines in favor of leaves in larger-bodied primates like woolly spider and howler monkeys.

“We examined dietary data to quantify how much different primate species feed on fruit, leaves and insects – particularly in relation to their body size. We found that different species vary widely in the amount and diversity of fruits that they eat, as well as the overall contribution of fruit to their diets,” lead researcher Dr Joseph Hawes, from UEA’s School of Environmental Sciences, said in a statement.

Hawes said they found the diet of medium-sized primates is most likely to be dominated by fruits, while small primates eat more insects because they provide a high-quality source of nutrients and calories.

“Larger monkeys eat a lot more foliage because their guts can tolerate high levels of cellulose and toxins – which are unpalatable or indigestible to smaller primates,” the researcher said. “Many primates easily consume their ‘five a day’, often within a single hour of active foraging. For example, a single group of several Amazonian primate species can consume as many as 45-50 species of fruit in a single day!”

One surprising finding from the study is that primates with wide geographic ranges do not necessarily consume a wider diversity of fruits as expected. Hawes said this could be because these species tend to be generalist feeders.

“Another surprise was that primates with higher prevalence of fruit in their diets were historically among the most poorly studied, meaning we still have a lot to learn about their importance as consumers and seed dispersers,” Hawes said.

This study could have some important implications for the conservation planning of threatened and area-demanding species, with forest habitat loss and severe forest degradation a major concern throughout the New World tropics.

“This is also critical to evaluate the roles of primates within forest food webs, particularly as seed dispersers for tropical forest plants,” Co-author Prof Carlos Peres, also from UEA, said in a statement.