JOSé MANUEL PANDO, Bolivia, April 28 (UPI) -- Biologists do their best to observe the behaviors of South America's saddleback tamarin, both from the vantage of the rainforest floor and by ascending into the canopy.
But keeping tabs on the diet of the squirrel-sized monkey is difficult. For that, researchers rely on monkey droppings collected from the forest floor.
In a recent study published in the American Journal of Physical Anthropology, researchers detailed the dietary habits of a group of Weddell's saddleback tamarins (Saguinus weddelli) in Bolivia. Over the course of three weeks, biologists found that a group of 20 tamarins consumed a vast range of insects -- including spiders, cockroaches, beetles, ants, grasshoppers, water midges, flies, wasps, moths, katydids and more.
A genetic analysis technique called high-throughput sequencing showed the monkeys ate invertebrates from 11 orders, 15 families and 12 genera.
"This is really exciting; it is the first time that we have been able to get detailed data like this," Elizabeth Mallott, an anthropologist and doctoral candidate at the University of Illinois, explained in a press release. "Their hand goes into a tree hole, and we don't know what they are coming out with. It is nice to finally be able to report the amount of diversity of what goes into their mouth. We wouldn't be able to do it without these molecular methods."
Researchers say their analysis of monkey droppings -- combined with their field observations -- offers new insight into the species' foraging strategies and prey preferences.
The genetic analysis method isn't foolproof. Researchers admit that some insects may prove more prevalent in the sequences not as a result of their frequent consumption but because of their larger DNA sequences. Further research is needed to more accurately illuminate the monkey's diet.
"You do have to be a little bit careful with this technique because it is so sensitive," said Ripan Malhi, a professor of anthropology at Illinois and a member of the Carl R. Woese Institute for Genomic Biology. "We have had conversations that maybe the tamarins weren't really eating that insect, maybe that was an insect that ate another insect, but we are still getting that DNA sequence."
Researchers are now using the same genetic analysis technique to study 3,000-year-old human feces found in the Southwestern U.S.