Study

Biofluorescence in the platypus (Ornithorhynchus anatinus)

Anich, Paula Spaeth; Anthony, Sharon; Carlson, Michaela; Gunnelson, Adam; Kohler, Allison M.; Martin, Jonathan G.; Olson, Erik R.

Mammalia, 2021

Peer-reviewedfield observationnot applicable

What they did

Museum specimens of platypus were illuminated with ultraviolet light and photographed with filters, and the emitted wavelengths recorded, following comparable observations in flying squirrels.

Studied in: Ornithorhynchus anatinus
Sample size: 3 museum specimens examined under ultraviolet light

What they found

Platypus fur fluoresces green to cyan under ultraviolet illumination. The effect was present in all specimens examined, both sexes, and from different collections.

What it means

The authors' reading, and ours. Where they differ, that difference is the point.

How the authors put it

Biofluorescence is present in platypus fur and may be more widespread among mammals than recognised, with a possible role in low-light conditions.

How NatureHQ reads it

Three museum specimens, and the finding is exactly that: platypus fur fluoresces. What has not been shown is that it matters. There is no evidence platypuses can see the effect, no evidence any other animal responds to it, and no evidence it does anything at all — and biofluorescence turns up in a great many biological materials for chemical reasons with no function attached. Subsequent work has found it in a long and growing list of mammals, which cuts both ways: it is more common than anyone thought, and being common makes a special explanation less likely rather than more. The honest framing is a real observation looking for a reason.

Limitations

Three preserved specimens; preservation chemistry can itself alter fluorescence.
No live animals were examined.
No function is demonstrated, and no evidence exists that platypuses or their predators can perceive it.