Study
Why do dolphins carry sponges?
Mann, Janet; Sargeant, Brooke L.; Watson-Capps, Jana J.; Gibson, Quincy A.; Heithaus, Michael R.
PLoS ONE, 2008
Bottlenose dolphins in Shark Bay, Western Australia, were observed over many years. Some individuals carry a marine sponge on the beak while foraging on the sea floor. Researchers compared the foraging behaviour, diet, time budgets and maternal lines of spongers and non-spongers.
- Studied in
- Tursiops aduncus
- Sample size
- 60 individually identified dolphins observed over a long-term studyDrawn from the Shark Bay population monitored since the 1980s.
Sponging is concentrated in particular matrilines, is learned almost exclusively by daughters from their mothers, and lets dolphins forage in deep channels for fish that lack swim bladders and cannot be found by echolocation alone. Spongers spend more time foraging alone than other dolphins.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Sponge-carrying is a socially transmitted foraging specialisation — the clearest case of material culture known in a marine mammal.
How NatureHQ reads it
A useful corrective to the assumption that tool use is about problem-solving cleverness. The sponge is protective equipment for a specific foraging niche, passed down a family line, and the dolphins that use it trade sociability for access to food nobody else can reach. Tool use here is an economic strategy, not a puzzle solved.
- Vertical transmission from mother to calf is inferred from association patterns rather than watched from start to finish.
- Genetic and social inheritance are difficult to separate fully in a matriline.
- Confined to one well-studied population; how general this is remains open.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Public Library of SciencePublished in a PLOS journal under CC BY 4.0.
doi.org/10.1371/journal.pone.0003868
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 2026-08-09.