Bonobo mothers have elevated urinary cortisol levels during early but not mid or late lactation

Niina O Nurmi, Ruth-Sophie Sonnweber (Corresponding author), Oliver Schülke, Liza Moscovice, Tobias Deschner, Gottfried Hohmann

Publications: Contribution to journalArticlePeer Reviewed

Abstract

In mammals, the costs of reproduction are biased towards females. Lactation is particularly energetically expensive, and behavioral and physiological data indicate that maternal effort during lactation induces energetic stress. Another source of stress in females is male aggression directed towards them when they are cycling. Evaluating the costs of reproduction in wild and mobile animals can be a challenging task, and requires detailed information on state-dependent parameters such as hormone levels. Glucocorticoid (GC) levels are indicative of nutritional and social stress, and are widely used to assess the costs of reproduction. We investigated variation in urinary levels of cortisol, the main GC in female bonobos (Pan paniscus), between and within reproductive stages. Female chimpanzees (Pan troglodytes), the closest living relative of the bonobos, are often exposed to intense aggression from males, which causes a significant rise in their cortisol levels during the phase of their maximum fecundity. In bonobos, males compete for access to fertile females, but aggressive male mating strategies are absent in this species. Therefore, we expected that GC levels of cycling female bonobos would be lower than those of lactating females. Due to the long period of offspring care in bonobos, we expected that GC levels would remain elevated into the late stage of lactation, when immatures gain body weight but may still be nursed and carried by their mothers. We found elevated urinary GC levels only during the early stage of lactation. The GC levels of cycling females did not differ from those in the mid or late lactation stage. Behavioral strategies of female bonobos may allow them to compensate for the elevated energetic demands of lactation and prolonged maternal care.
Original languageEnglish
Pages (from-to)215-225
Number of pages11
JournalPrimates
Volume64
Issue number2
Early online date24 Dec 2022
DOIs
Publication statusPublished - Mar 2023

Austrian Fields of Science 2012

  • 106056 Biological anthropology
  • 106054 Zoology
  • 106048 Animal physiology
  • 106038 Reproductive biology

Keywords

  • Reproductive stage
  • Pan paniscus
  • Energetic stress
  • Circadian rhythm
  • Glucocorticoids

Fingerprint

Dive into the research topics of 'Bonobo mothers have elevated urinary cortisol levels during early but not mid or late lactation'. Together they form a unique fingerprint.

Cite this