What is cooperative breeding in mammals and birds? Removing definitional barriers for comparative research

Yitzchak Ben Mocha, Sophie Scemama de Gialluly, Michael Griesser, Shai Markman

Research output: Contribution to journalArticlepeer-review


Cooperative breeding (i.e. when alloparents care for the offspring of other group members) has been studied for nearly a century. Yet, inconsistent definitions of this breeding system still hamper comparative research. Here, we identify two major inconsistencies, discuss their consequences and propose a way forward. First, some researchers restrict the term ‘cooperative breeding’ to species with non-breeding alloparents. We show that such restrictive definitions lack distinct quantitative criteria to define non-breeding alloparents. This ambiguity, we argue, reflects the reproductive-sharing continuum among cooperatively breeding species. We therefore suggest that cooperative breeding should not be restricted to the few species with extreme reproductive skew and should be defined independent of the reproductive status of alloparents. Second, definitions rarely specify the type, extent and prevalence of alloparental care required to classify species as cooperative breeders. We thus analysed published data to propose qualitative and quantitative criteria for alloparental care. We conclude by proposing the following operational definition: cooperative breeding is a reproductive system where >5% of broods/litters in at least one population receive species-typical parental care and conspecifics provide proactive alloparental care that fulfils >5% of at least one type of the offspring's needs. This operational definition is designed to increase comparability across species and disciplines while allowing to study the intriguing phenomenon of cooperative breeding as a behaviour with multiple dimensions.

Original languageEnglish
Pages (from-to)1845-1861
Number of pages17
JournalBiological Reviews
Issue number6
StatePublished - Dec 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.


  • alloparental care
  • birds
  • breeding monopolisation
  • communal breeding
  • comparative research
  • cooperative breeding
  • definition
  • helping
  • mammals
  • reproductive skew

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • General Biochemistry, Genetics and Molecular Biology


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