Study
Arterio-venous heat exchange systems in the Jackass penguin Spheniscus demersus
Frost, P. G. H.; Siegfried, W. R.; Greenwood, P. J.
Journal of Zoology, 1975
The vascular anatomy of the flippers and legs of African penguins was described by dissection and casting, identifying where arteries and veins run in close apposition and estimating the heat-exchange consequences.
- Studied in
- Spheniscus demersus
- Sample size
- anatomical dissection and vascular casting
Arteries supplying the flippers and legs are surrounded by bundles of returning veins, so outgoing warm blood transfers heat to incoming cold blood before reaching the extremity. The extremities consequently run close to ambient temperature while the core does not lose heat through them.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Counter-current vascular arrangements in the flippers and legs conserve core heat, and the same anatomy can be bypassed to dump heat when the bird overheats.
How NatureHQ reads it
This is the mechanism behind the fact that most surprises people: a penguin's feet are supposed to be cold, and warming them would be the failure state. The same arrangement solves the opposite problem too, because a penguin on a warm beach needs to shed heat, and the exchange can be bypassed to do it. It is worth knowing that this anatomy is not a penguin invention — the same solution appears in wading birds, in whale flippers and in human limbs to a lesser degree — which makes it a good example of a shared engineering answer rather than a species curiosity.
- A temperate species, so the description is of the general arrangement rather than a polar extreme.
- Anatomical, with heat transfer inferred from structure rather than measured in a live diving bird.
- Older work; quantitative modelling of exchange efficiency came later.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Wiley journalsPublished in a Wiley journal.
doi.org/10.1111/j.1469-7998.1975.tb01398.x
This reference was resolved automatically against Crossref on 2026-08-11.
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