Study
Two levels of alliance formation among male bottlenose dolphins
Connor, Richard C.; Smolker, Rachel A.; Richards, Andrew F.
Proceedings of the National Academy of Sciences, 1992
Individually recognisable male dolphins in Shark Bay were tracked over years, recording which males associated with which, and what those groupings did when consorting with or competing over females.
- Studied in
- Tursiops aduncus
- Sample size
- individually identified males tracked across years in Shark Bay
Males form stable pairs and trios that cooperate to herd individual females. Those small alliances themselves combine into larger second-order alliances that take females from other alliances and defend against the same.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Bottlenose dolphins form nested alliances — alliances of alliances — a level of social structure otherwise known mainly from humans.
How NatureHQ reads it
The nesting is what makes this significant rather than the cooperation. Plenty of animals cooperate in pairs; keeping track of who your partners are, and separately of which other groups your group works with, requires holding a two-tier social map. It is also worth noting what the alliances are for: coercive herding of females, which is a long way from the benign social intelligence the popular version of dolphins implies.
- One population, in one bay, with an unusually long observation history.
- Association is inferred from co-occurrence, which can overstate social bonds.
- Indo-Pacific bottlenose dolphins; the pattern is not established across dolphins generally.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Proceedings of the National Academy of SciencesPublished in PNAS.
This reference was resolved automatically against Crossref on 2026-08-11.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-10.