Biology subjects

Salali, G. D.

Publications and source records attributed to Salali, G. D..

4 recordsLinked to original sources

bioRxiv2023

Patterns of physical activity in hunter-gatherer children compared with US and UK children.

Sedentary lifestyles, mismatched with our active foraging history, contribute to escalating rates of non-communicable diseases. Contemporary hunter-gatherers appear to be highly active, but little is known about physical activity levels in hunter-gatherer children. We analysed 150 days of accelerometer data from 51 BaYaka hunter-gatherer children (aged 3-18) in the Republic of Congo, comparing it with British and American children (MCS and NHANES). BaYaka children were highly active, engaging in over 3 hours of moderate-to-vigorous physical activity (MVPA) daily, surpassing British adolescents by over 70 minutes. In US children activity declined with age; while in BaYaka children activity increased with age, unaffected by gender. Reflecting their foraging lifestyle, activity patterns varied within and between days, yet all children consistently rose with the sun. These findings highlight the impact of a foraging upbringing on childrens activity levels, providing a benchmark for understanding childhood physical activity and wellbeing.

evolutionary biology↗

bioRxiv2022

Hunter-gatherer oral microbiomes are shaped by contact network structure

Ancestral humans evolved a complex social structure still observed in extant hunter-gatherers. Here we investigate the effects of extensive sociality and mobility on the oral microbiome of 138 Agta hunter-gatherers from the Philippines. Comparisons of microbiome composition showed that the Agta are more similar to Central African Bayaka hunter-gatherers than to neighboring farmers. We also defined the Agta social microbiome as a set of 137 oral bacteria (only 7% of 1980 amplicon sequence variants) significantly influenced by social contact (quantified through wireless sensors of short-range interactions). We show that interaction networks covering large areas, and their strong links between close kin, spouses, and even unrelated friends, can significantly predict bacterial transmission networks across Agta camps. Finally, more central individuals to social networks are also bacterial supersharers. We conclude that hunter-gatherer social microbiomes, which are predominantly pathogenic, were shaped by evolutionary tradeoffs between extensive sociality and disease spread.

microbiology↗

bioRxiv2021

Bitter taste perception in BaYaka hunter-gatherers

Aversion towards bitter tastes evolved across vertebrate species to enable the recognition of harmful plant toxins. Most studies to date have investigated the variation in bitter taste sensitivity between human populations. However, there is a lack of research investigating phenotypic plasticity and the variation in bitter taste perception within the same population. Here we examined bitter taste perception among the Mbendjele BaYaka hunter-gatherers from Congo, a group of forest hunter-gatherers who exhibit a variation in their levels of market integration. We conducted an experiment using phenylthiocarbamide (PTC) and thiourea infused paper strips and compared the prevalence of bitter tasting phenotypes between the BaYaka who grew up in town and forest camps. We found that 45.1% of BaYaka experience PTC as bitter, and 42.5% experience thiourea as bitter. There were no sex and age differences in bitter taste perception. Despite a shared genetic background, we found that BaYaka who grew up in town were more sensitive to bitter taste than those living in the forest, suggesting a developmental component in taste perception. We suggest that a decreased use of traditional plant medicine in town-born BaYaka may underlie this variation in bitter taste perception.

ecology↗

bioRxiv2020

Acoustic regularities in infant-directed vocalizations across cultures

The forms of many species vocal signals are shaped by their functions1-15. In humans, a salient context of vocal signaling is infant care, as human infants are altricial16, 17. Humans often alter their vocalizations to produce "parentese", speech and song produced for infants that differ acoustically from ordinary speech and song18-35 in fashions that have been proposed to support parent-infant communication and infant language learning36-39; modulate infant affect33, 40-45; and/or coordinate communicative interactions with infants46-48. These theories predict a form-function link in infant-directed vocalizations, with consistent acoustic differences between infant-directed and adult-directed vocalizations across cultures. Some evidence supports this prediction23, 27, 28, 32, 49-52, but the limited generalizability of individual ethnographic reports and laboratory experiments53 and small stimulus sets54, along with intriguing reports of counterexamples55-62, leave the question open. Here, we show that people alter the acoustic forms of their vocalizations in a consistent fashion across cultures when speaking or singing to infants. We collected 1,615 recordings of infant- and adult-directed singing and speech produced by 410 people living in 21 urban, rural, and small-scale societies, and analyzed their acoustic forms. We found cross-culturally robust regularities in the acoustics of infant-directed vocalizations, such that infant-directed speech and song were reliably classified from acoustic features found across the 21 societies studied. The acoustic profiles of infant-directedness differed across language and music, but in a consistent fashion worldwide. In a secondary analysis, we studied whether listeners are sensitive to these acoustic features, playing the recordings to 51,065 people recruited online, from many countries, who guessed whether each vocalization was infant-directed. Their intuitions were largely accurate, predictable in part by acoustic features of the recordings, and robust to the effects of linguistic relatedness between vocalizer and listener. By uniting rich cross-cultural data with computational methods, we show links between the production of vocalizations and cross-species principles of bioacoustics, informing hypotheses of the psychological functions and evolution of human communication.

animal behavior and cognition↗