Dear All, We would like to draw attention to our recently published paper on the structural and functional properties of the conducting airways in marine mammals. If you would like a pdf copy of the paper, please send an e-mail to: Andreas Fahlman: andreas.fahlman@tamucc.edu or Colby Moore: colby_moore@baylor.edu CITATION Moore, C., Moore, M.J., Trumble, S., Niemeyer, M., Lentell, B., McLellan, W., Costidis, A., Fahlman, A., A Comparative Analysis of Marine Mammal Tracheas. Journal of Experimental Biology 217, 1154 (2014). ABSTRACT In 1940, Scholander suggested that stiffened upper airways remained open and received air from highly compressible alveoli during marine mammal diving. There are few data available on the structural and functional adaptations of the marine mammal respiratory system. The aim of this research was to investigate the anatomical (gross) and structural (compliance) characteristics of excised marine mammal tracheas. Here, we defined different types of tracheal structures, categorizing pinniped tracheas by varying degrees of continuity of cartilage (categories 1–4) and cetacean tracheas by varying compliance values (categories 5A and 5B). Some tracheas fell into more than one category along their length; for example, the harbor seal (Phoca vitulina) demonstrated complete rings cranially, and as the trachea progressed caudally, tracheal rings changed morphology. Dolphins and porpoises had less stiff, more compliant spiraling rings while beaked whales had very stiff, less compliant spiraling rings. The pressure–volume (P–V) relationships of isolated tracheas from different species were measured to assess structural differences between species. These findings lend evidence for pressure-induced collapse and re-inflation of lungs, perhaps influencing variability in dive depth or ventilation rates of the species investigated. -- Andreas Fahlman Department of Life Sciences Texas A&M- Corpus Christi 6300 Ocean Dr Unit 5892 Corpus Christi, TX 78412 Ph. +1-361-825-3489 Fax +1-361-825-2025 mail: andreas.fahlman@tamucc.edu web: comparativephysiology.webs.com -- Andreas Fahlman Department of Life Sciences Texas A&M- Corpus Christi 6300 Ocean Dr Unit 5892 Corpus Christi, TX 78412 Ph. +1-361-825-3489 Fax +1-361-825-2025 mail: andreas.fahlman@tamucc.edu web: comparativephysiology.webs.com