1 Seyfarth R.M.

Cheney D.L. The evolutionary origins of friendship.

2 Brent L.J.

Chang S.W.

Gariépy J.F.

Platt M.L. The neuroethology of friendship.

3 Brent L.J.N.

Ruiz-Lambides A.

Platt M.L. Family network size and survival across the lifespan of female macaques.

4 McFarland R.

Murphy D.

Lusseau D.

Henzi S.P.

Parker J.L.

Pollet T.V.

Barrett L. The ‘strength of weak ties’ among female baboons: fitness-related benefits of social bonds.

5 Riehl C.

Strong M.J. Stable social relationships between unrelated females increase individual fitness in a cooperative bird.

6 Carter G.G.

Farine D.R.

Wilkinson G.S. Social bet-hedging in vampire bats.

7 Connor R.C.

Krützen M. Male dolphin alliances in Shark Bay: changing perspectives in a 30-year study.

8 Kern J.M.

Radford A.N. Social-bond strength influences vocally mediated recruitment to mobbing.

1 Seyfarth R.M.

Cheney D.L. The evolutionary origins of friendship.

9 Henzi S.P.

Barrett L. Coexistence in female-bonded primate groups.

10 Kaburu S.S.

Newton-Fisher N.E. Bystanders, parcelling, and an absence of trust in the grooming interactions of wild male chimpanzees.

11 Newton-Fisher N.E.

Kaburu S.S. Grooming decisions under structural despotism: the impact of social rank and bystanders among wild male chimpanzees.

12 Farine D.R.

Whitehead H. Constructing, conducting and interpreting animal social network analysis.

13 Farine D.R. A guide to null models for animal social network analysis.

14 Farine D.R.

Firth J.A.

Aplin L.M.

Crates R.A.

Culina A.

Garroway C.J.

Hinde C.A.

Kidd L.R.

Milligan N.D.

Psorakis I.

et al. The role of social and ecological processes in structuring animal populations: a case study from automated tracking of wild birds.

15 He P.

Maldonado-Chaparro A.A.

Farine D.R. The role of habitat configuration in shaping social structure: a gap in studies of animal social complexity.

16 Puga-Gonzalez I.

Hildenbrandt H.

Hemelrijk C.K. Emergent patterns of social affiliation in primates, a model.

1 Seyfarth R.M.

Cheney D.L. The evolutionary origins of friendship.

9 Henzi S.P.

Barrett L. Coexistence in female-bonded primate groups.

10 Kaburu S.S.

Newton-Fisher N.E. Bystanders, parcelling, and an absence of trust in the grooming interactions of wild male chimpanzees.

11 Newton-Fisher N.E.

Kaburu S.S. Grooming decisions under structural despotism: the impact of social rank and bystanders among wild male chimpanzees.

17 Barrett L.

Henzi S.P.

Weingrill T.

Lycett J.E.

Hill R.A. Market forces predict grooming reciprocity in female baboons.

Social bonds, maintained by mutual investments of time and energy, have greatly influenced the evolution of social cognition and cooperation in many species [e.g.,]. However, there are two pitfalls regarding “social bonds” as an explanation for social structure and cooperation []. First, studies often incorrectly assume that frequent association implies partner fidelity based on mutual social preference, but even seemingly complex nonrandom interaction networks can emerge solely from habitat or spatial structure []. Second, the false appearance of partner fidelity can result from stable options in the “partner market” []. For instance, individuals might preferentially groom the same partner, even if the decision depends entirely on the immediate costs and benefits rather than relationship history. Given these issues, a key challenge has been testing the extent to which social structure is driven by the intrinsic relationship history versus the extrinsic physical and social environment. If stable bonds exist, they should persist even if the individuals are moved to a dramatically different physical and social environment. We tested this prediction by tracking social relationships among common vampire bats ( Desmodus rotundus) moved from the lab to the wild. We show that allogrooming and food sharing among female vampire bats induced in captivity over 22 months predicted their assortativity and association rates when we subsequently tracked them in the wild with custom-made high-resolution proximity sensors. The persistence of many relationships across different physical and social environments suggests that social structure is caused by both extrinsic constraints and intrinsic partner fidelity.