FRG-Funded Research Breaks New Ground in Understanding Sleep Patterns

October 30, 2015

In Fall 2013 UNM doctoral candidate Gandhi Yetish received Field Research Grant (FRG) funding from the LAII to partially support research focused on sleep patterns among the Tsimane in Bolivia. This field research contributed to breaking new ground in understanding sleep patterns, and was recently published as "Natural Sleep and its Seasonal Variations in Three Pre-industrial Societies" in the journal Current Biology, with Yetish as lead author.


The research has led to widespread interest and resulted in articles such as the NYTimes' "Do We Really Need to Sleep 7 Hours a Night?"; Scientific American's Modern Hunter-Gatherers Probably Get Less Sleep Than You Do; The Atlantic's "What You Can Learn from Hunter-Gatherers' Sleeping Patterns; and National Geographics' People Without Electricity Don't Get 8 Hours' Sleep Either, among others. Below is an excerpt of a recent UNM Newsroom article covering Yetish's research. For more information, read the complete article on "Early to Bed and Early to Rise?" by Karen Wentworth.

  • Researchers examined the sleep patterns of three societies of hunter-gatherers; the Hadza in northern Tanzania, south of the equator, the Kalahari San in northeast Namibia, and the Tsimane who live close to the Maniqui River in Bolivia. The San are not currently nomadic, but live in villages as hunter gatherers. Yetish says they found that these hunter-gatherers and hunter-horticulturalists sleep an average of 6.4 hours a day, rarely nap and all show similar sleep amounts and timing. The research concludes that temperature seems to regulate sleep duration and timing since the members of the groups went to sleep as daytime temperatures began to drop and awoke when nighttime temperatures were at their lowest. The researchers could not find a tight link to ambient light levels and sleep patterns.

    Yetish is a student of UNM Professor of Anthropology Hilliard Kaplan, who has studied the Tsimane in Bolivia for decades. Yetish went to Bolivia in 2013 with a specific interest in studying when people should want to sleep more, and when they should want to sleep less and why. While in Bolivia he was contacted by University of California Neurobiology Research Professor Jerome Siegel who wanted to coordinate sleep research among several hunter-gatherer groups in different parts of the world.

    Yetish says this has been a great learning experience for him. “I’m hoping to continue my research into the evolution of human sleep and its ecological context to inform the way we think about our own sleep in the U.S.,” he said.

LAII Field Research Grants provide support for graduate students in any UNM department to conduct field work in Latin America. FRGs are meant to assist students in obtaining their first or second field research experience in Latin America. The grants are generally for fairly brief periods of research (typically two weeks to four months) and provide funding for airfare, in-country transportation and some expenses in the field. Awards are given annually each spring. For more information, see the complete description of Field Research Grant funding.

To learn about previous field research grant recipients, please see the LAII's FRG profiles and photography albums. Current awardees will be added shortly.