Tuesday, Jul 28, 2026 The claims desk. Receipts included. POWERED BY LENZ ↗
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The Claim

In males living in the Kalahari environment, elevated circulating testosterone indicates that a sexual-selection-related physiological axis remains active in the population despite thermal stressors.

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The Short Version

The claim is not supported by the cited evidence. The only directly relevant study of desert-dwelling human males does not show elevated testosterone, and the broader heat-stress literature mostly points in the opposite direction: thermal stress tends to suppress testosterone and impair reproductive physiology. The inference to an active sexual-selection-related axis in Kalahari males is therefore unproven.

Caveats

  • Comparable hormone levels are not evidence of elevated testosterone; the claim overstates what the human Kalahari-related data show.
  • Most supporting biology comes from cross-species or laboratory heat-stress studies, which cannot establish this specific pattern in Kalahari human males.
  • The causal interpretation is unsupported: testosterone alone does not demonstrate that a sexual-selection-related physiological axis remains active under thermal stress without direct population-specific measurements.

The Receipts

  1. Effects of Heat Stress-Induced Sex Hormone Dysregulation on Male Adolescents

    PubMed Central

  2. Endocrinology of year-round reproduction in a highly seasonal habitat: Environmental variability in testosterone and glucocorticoids in baboon males

    The American Journal of Physical Anthropology (Wiley Online Library)

  3. Global warming and testis function: A challenging crosstalk in between environmental temperature and fertility

    PubMed Central

  4. Testosterone mediates hyperthermic response of mice to heat ...

    PubMed

  5. Life history and environment predict variation in testosterone across birds

    Oxford Academic

  6. Exertional heat stroke on fertility, erectile function, and testicular morphology in male rats

    Nature

  7. Endocrine Effects of Repeated Hot Thermal Stress and Cold Water ...

    PMC

  8. Reduced fertility indices as a consequence of a simulated heatwave ...

    University of Pretoria Repository

  9. Variation in Circulating Testosterone during Mating Predicts Reproductive Success in a Wild Songbird

    Frontiers

  10. The effect of stress on testosterone and sexual function

    Nature

+ 23 more sources — see the full list on Lenz

Filed Under

Kalahari DesertSexual SelectiontestosteroneThermal Stress

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