Comparative gas conductance of the avian egg shell

A. Ar, C. Paganelli

Research output: Contribution to journalArticlepeer-review


Ventilation, a quantity which expresses convective conductance of the gas transport path, is proportional to metabolic body weight in mammals. The corresponding quantity in avian eggs is diffusive conductance (G) of the shell. Using water vapor as a test gas, the authors measured the variation in G with weight in eggs ranging from 1.5 to 1500 g in 29 avian species. G(H2O) in mg day-1 torr-1 increased with egg weight (W in g). All gases using the same diffusive path must vary with weight to the same power. Thus the conductances of mammalian lung and avian egg shell have closely similar dependencies on weight. However, there is a qualitative difference between the 2. Convective conductance depends only on ventilation, but G is the product of shell area (A) and permeability (K), i.e., G = A x K. The combined effects of changing area and permeability give rise to the observed change in G. The close agreement between the weight dependencies of convective and diffusive conductance suggests that the same evolutionary optimization rules operate in both types of gas transport systems.

Original languageEnglish
Pages (from-to)708
Number of pages1
JournalFederation Proceedings
Issue number3 (I)
StatePublished - 1973
Externally publishedYes


Dive into the research topics of 'Comparative gas conductance of the avian egg shell'. Together they form a unique fingerprint.

Cite this