Study
Olfaction contributes to pelagic navigation in a coastal shark
Nosal, Andrew P.; Chao, Yi; Farrara, John D.; Chai, Fei; Hastings, Philip A.
PLoS ONE, 2016
Leopard sharks were transported nine kilometres offshore and released, half with their olfactory sense temporarily blocked, and their return paths were tracked acoustically.
- Studied in
- Triakis semifasciata
- Sample size
- 26 leopard sharks displaced offshore and tracked
Sharks with an intact sense of smell headed shoreward in a comparatively direct line; sharks with olfaction blocked took much more tortuous paths and ended significantly further from shore.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Olfactory cues contribute to navigation over kilometres in the open sea, alongside other senses.
How NatureHQ reads it
This is the study to reach for when someone says a shark can smell a drop of blood in an Olympic swimming pool from miles away. The truth is more interesting and much less lurid: smell is a *navigational* input working over kilometres in a chemically structured ocean, not a blood-detection superpower, and the sharks with the sense removed still got home — just badly.
- One coastal species over a short displacement; open-ocean sharks were not tested.
- Olfactory blocking may have side effects beyond smell.
- Which chemical gradient is being followed is not identified.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Sharks
Sharks smell well, and use it to navigate — not to detect a drop of blood from miles off
Smell, and how far it really works
A shark following a smell turns towards whichever nostril detected it first, not towards the side where it is strongest — because in a real plume, strength tells you almost nothing.
Published by: Public Library of SciencePublished in a PLOS journal under CC BY 4.0.
doi.org/10.1371/journal.pone.0143758
Checked against Crossref on 2026-09-28, and they agree on the title, the authors and the year.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-09.