Seasonal reproductive endothermy in tegu lizards

Author(s)

Tattersall, Glenn J. ^{[1, 2]} ; Leite, Cleo A. C. ^{[3, 2]} ; Sanders, Colin E. ^{[3, 4]} ; Cadena, Viviana ^{[1, 5]} ; Andrade, Denis V. ^{[2, 6]} ; Abe, Augusto S. ^{[2, 6]} ; Milsom, William K. ^{[2, 7]}

Affiliation

^[1] Brock Univ, Dept Biol Sci, St Catharines, ON L2S 3A1 - Canada

^[2] Natl Inst Sci & Technol Comparat Physiol INCT Fis, BR-13505060 Sao Paulo - Brazil

^[3] Univ Fed Sao Carlos, Dept Physiol Sci, Sao Paulo - Brazil

^[4] Univ Alberta, Edmonton, AB T6G 2R3 - Canada

^[5] Univ Melbourne, Dept Zool, Melbourne, Vic 3010 - Australia

^[6] Sao Paulo State Univ UNESP, Dept Zool, BR-13506900 Rio Claro - Brazil

^[7] Univ British Columbia, Dept Zool, 6270 Univ Blvd, Vancouver, BC V6T 1Z4 - Canada

• Document type: Journal article
• Source: SCIENCE ADVANCES; v. 2, n. 1 JAN 2016.
• Web of Science Citations: 33

Abstract

With some notable exceptions, small ectothermic vertebrates are incapable of endogenously sustaining a body temperature substantially above ambient temperature. This view was challenged by our observations of nighttime body temperatures sustained well above ambient (up to 10 degrees C) during the reproductive season in tegu lizards (similar to 2 kg). This led us to hypothesize that tegus have an enhanced capacity to augment heat production and heat conservation. Increased metabolic rates and decreased thermal conductance are the same mechanisms involved in body temperature regulation in those vertebrates traditionally acknowledged as ``true endotherms{''}: the birds and mammals. The appreciation that a modern ectotherm the size of the earliest mammals can sustain an elevated body temperature through metabolic rates approaching that of endotherms enlightens the debate over endothermy origins, providing support for the parental care model of endothermy, but not for the assimilation capacity model of endothermy. It also indicates that, contrary to prevailing notions, ectotherms can engage in facultative endothermy, providing a physiological analog in the evolutionary transition to true endothermy. (AU)

• FAPESP's process: 13/04190-9 - Thermal physiology and water balance in anurans along an altitudinal gradient in the Atlantic Rainforest
• Grantee: Denis Otavio Vieira de Andrade
• Support Opportunities: Regular Research Grants
• FAPESP's process: 08/57712-4 - The National Institute of Comparative Physiological Research
• Grantee: Augusto Shinya Abe
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 10/05473-6 - Ecophysiology of Bokermannohyla alvarengai (Bokermann 1956): an endemic treefrog from altitude regions in Brazil.
• Grantee: Denis Otavio Vieira de Andrade
• Support Opportunities: Regular Research Grants