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To address claims of human exceptionalism, we determine where humans fit within the greater mammalian distribution of reproductive inequality. We show that humans exhibit lower reproductive skew (i.e., inequality in the number of surviving offspring) among males and smaller sex differences in reproductive skew than most other mammals, while nevertheless falling within the mammalian range. Additionally, female reproductive skew is higher in polygynous human populations than in polygynous nonhumans mammals on average. This patterning of skew can be attributed in part to the prevalence of monogamy in humans compared to the predominance of polygyny in nonhuman mammals, to the limited degree of polygyny in the human societies that practice it, and to the importance of unequally held rival resources to women's fitness. The muted reproductive inequality observed in humans appears to be linked to several unusual characteristics of our species-including high levels of cooperation among males, high dependence on unequally held rival resources, complementarities between maternal and paternal investment, as well as social and legal institutions that enforce monogamous norms.

The goal of assessing psychosocial stress as a process and outcome in naturalistic (i.e., field) settings is applicable across the social, biological, and health sciences. Meaningful measurement of biology-in-context is, however, far from simple or straightforward. In this brief methods review, we introduce theoretical framings, methodological conventions, and ethical concerns around field-collection of markers of psychosocial stress that have emerged from 50 years of research at the intersection of anthropology and human biology. Highlighting measures of psychosocial stress outcomes most often used in biocultural studies, we identify the circumstances under which varied measures are most appropriately applied and provide examples of the types of cutting-edge research questions these measures can address. We explain that field-based psychosocial stress measures embedded in different body systems are neither equivalent nor interchangeable, but this recognition strengthens the study of stress as always simultaneously cultural and biological, situated in local ecologies, social--political structures, and time.

Background: Aquí Entre Nos (Between Us) is a community-based participatory research project to engage rural, ethno-racially diverse hotel housekeepers in a right to work state during a time of national anti-immigrant policy, wildfires and emergence of a global pandemic. Objectives: We aimed to (1) build trust and social support with the hotel housekeeping community, (2) learn about the occupational health, safety, and workers' rights challenges, strategies, and solutions held by workers, and (3) develop a workforce-driven research and action agenda to improve labor and health conditions. Methods: Participatory mixed methods rooted in popular education are described to form an advisory board and engage the workforce. Lessons Learned: Trusted relationships built through community organizing around immigration, housing, and minimum wage were critical to engage and drive a worker centered research agenda. Conclusions: Despite challenges, housekeeper advisors defined a research agenda that addressed immediate-and long-term needs of the workforce. [ABSTRACT FROM AUTHOR]

Objectives Methods Results Conclusions The hypothalamic–pituitary–adrenal (HPA) axis and its primary end product, the glucocorticoid cortisol, are major components of the evolved human stress response. However, most studies have examined these systems among populations in high‐income settings, which differ from the high pathogen and limited resource contexts in which the HPA axis functioned for most of human evolution.We investigated variability in diurnal salivary cortisol patterns among 298 Indigenous Shuar from Amazonian Ecuador (147 males, 151 females; age 2–86 years), focusing on the effects of age, biological sex, and body mass index (BMI) in shaping differences in diurnal cortisol production. Saliva samples were collected three times daily (waking, 30 minutes post‐waking, evening) for three consecutive days to measure key cortisol parameters: levels at waking, the cortisol awakening response, the diurnal slope, and total daily output.Age was positively associated with waking levels and total daily output, with Shuar juveniles and adolescents displaying significantly lower levels than adults (p < .05). Sex was not a significant predictor of cortisol levels (p > .05), as Shuar males and females displayed similar patterns of diurnal cortisol production across the life course. Moreover, age, sex, and BMI significantly interacted to moderate the rate of diurnal cortisol decline (p = .027). Overall, Shuar demonstrated relatively lower cortisol concentrations than high‐income populations.This study expands the documented range of global variation in HPA axis activity and diurnal cortisol production and provides important insights into the plasticity of human stress physiology across diverse developmental and socioecological settings. [ABSTRACT FROM AUTHOR]

Objective: Cytomegalovirus (CMV) infection is associated with age‐related chronic disease, and co‐infection with Epstein‐Barr virus (EBV) may compound disease risk. We aimed to assess the frequency of CMV infection and its relationship with age among EBV seropositive individuals in an Indigenous Amazonian population. Methods: We report concentrations of CMV and EBV antibodies in dried blood spot samples collected from 157 EBV positive Shuar participants aged 15–86 years (60.5% female) to assess CMV infection rate. We used logistic and linear regression models to examine associations among CMV, EBV, and age, adjusting for sex, geographic region, and body mass index. Results: Nearly two‐thirds (63.1%) of EBV seropositive participants were also CMV seropositive. A 1‐year increase in age was associated with 3.4% higher odds of CMV infection (OR [95% CI]: 1.034 [1.009–1.064], p =.012), but CMV antibody concentration was not significantly associated with age or EBV antibody concentration among co‐infected individuals. Conclusions: Herpesvirus‐related immunosenescence may be important to understanding chronic disease risk among Shuar. Future studies should further explore the role of co‐infection in shaping age‐related changes in immune function. [ABSTRACT FROM AUTHOR]

Objective: Anemia is an important global health challenge. We investigate anemia prevalence among Indigenous Shuar of Ecuador to expand our understanding of population‐level variation, and to test hypotheses about how anemia variation is related to age, sex, and market integration. Methods: Hemoglobin levels were measured in a total sample of 1650 Shuar participants (ages 6 months to 86 years) from 46 communities between 2008 and 2017 to compare anemia prevalence across regions characterized by different levels of market integration. Results: Shuar anemia rates among children under 15 years (12.2%), adult women (10.5%), and adult men (5.3%) were less than half of those previously documented in other neo‐tropical Indigenous populations. Anemia prevalence did not vary between more traditional and market integrated communities (OR = 0.47, p =.52). However, anemia was negatively associated with body mass index (OR = 0.47, p =.002). Conclusions: Compared to other South American Indigenous populations, anemia prevalence is relatively low among Shuar of Ecuador and invariant with market integration. Understanding this pattern can provide valuable insights into anemia prevention among at‐risk populations. [ABSTRACT FROM AUTHOR]