Publication Date:
1999-06-05
Description:
A controversial hypothesis has proposed that lizards are subject to a speed-dependent axial constraint that prevents effective lung ventilation during moderate- and high-speed locomotion. This hypothesis has been challenged by results demonstrating that monitor lizards (genus Varanus) experience no axial constraint. Evidence presented here shows that, during locomotion, varanids use a positive pressure gular pump to assist lung ventilation. Disabling the gular pump reveals that the axial constraint is present in varanids but it is masked by gular pumping under normal conditions. These findings support the prediction that the axial constraint may be found in other tetrapods that breathe by costal aspiration and locomote with a lateral undulatory gait.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Owerkowicz, T -- Farmer, C G -- Hicks, J W -- Brainerd, E L -- 1F32-HL09796-01/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1999 Jun 4;284(5420):1661-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA. towerkow@oeb.harvard.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10356394" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Energy Metabolism
;
Gait
;
Iguanas/physiology
;
Lizards/*physiology
;
*Locomotion
;
Oxygen Consumption
;
Pharynx/*physiology
;
Pressure
;
Pulmonary Gas Exchange
;
*Pulmonary Ventilation
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
