CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Australian Journal of Zoology   
Australian Journal of Zoology
Journal Banner
  Evolutionary, Molecular and Comparative Zoology
blank image Search
blank image blank image
blank image
  Advanced Search

Journal Home
About the Journal
Editorial Structure
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Sample Issue
For Authors
General Information
Author Instructions
Submit Article
Open Access
Awards and Prizes
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter LinkedIn


Article << Previous     |     Next >>   Contents Vol 55(5)

The heterothermic loophole exploited by penguins

Daniel B. Thomas A B, R. Ewan Fordyce A

A Department of Geology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
B Corresponding author. Email: thoda073@student.otago.ac.nz
PDF (175 KB) $25
 Export Citation


Penguins are generally smaller than the predicted minimum body size for marine endotherms. Anatomical observations of the little blue penguin (Eudyptula minor) suggest that extant penguins actively defeat the lower size threshold using regional heterothermy. The wing arteries in the little blue penguin form a humeral plexus, a series of three parallel arteries (including the marginal artery) that stem from the axillary artery, replacing a single brachial artery. Each artery of the plexus is associated with at least two veins to form a counter current heat-retention system. The humeral plexus thus restricts heat from entering distal areas of the wing and dissipating into seawater, ultimately reducing the bulk mass required for heat production and insulation. Humeral plexi are confirmed as a synapomorphic character of the Spheniscinae, with the humeral plexus of E. minor most similar to that of the African penguin Spheniscus demersus. The humeral plexus represents a loophole in body size minima of marine endotherms and offers insight into the ecology of living penguins.

Subscriber Login

Legal & Privacy | Contact Us | Help


© CSIRO 1996-2015