The Development of Endothermy during Pouch Life in the Eastern Barred Bandicoot (Perameles gunnii), a Marsupial

• Published in: Physiological and biochemical zoology 2006-05, Vol.79 (3), p.468-473
• Main Authors: Ikonomopoulou, Maria P., Rose, Randy W.
• Format: Article
• Language: English
• Subjects: Age Factors; Ambient temperature; Animals; Basal Metabolism - physiology; Body temperature; Body Temperature Regulation - physiology; Cold Temperature; Developmental biology; Female; Lactation; Male; Marsupialia - metabolism; Marsupialia - physiology; Marsupials; Metabolism; Norepinephrine; Norepinephrine - pharmacology; Oxygen consumption; Oxygen Consumption - physiology; Regression Analysis; Tasmania; Thermogenesis; Thermoregulation
• ISSN: 1522-2152; 1537-5293
• DOI: 10.1086/502819

Marsupials are born ectothermic and gradually become endothermic during pouch occupancy. In order to study the timing of this transition, we measured the metabolic rates of eight pouch‐young eastern barred bandicoots (Perameles gunnii) at 25°C (the thermoneutral zone of adults), at 35°C (pouch temperature), and after injection with norepinephrine. From 5 to 7 wk of age, oxygen consumption ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\dot{\mathrm{V}}\textsc{$o$}_{2}$ \end{document} ) was higher at 35°C than at 25°C. At 8 wk, \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\dot{\mathrm{V}}\textsc{$o$}_{2}$ \end{document} was significantly higher at 25°C than at 35°C. Norepinephrine administration at 5 and 6 wk had no effect on metabolic rate, but at 8 wk, near pouch vacation, it resulted in a significant increase in metabolic rate. Our results indicate that signs of thermoregulation forP. gunniibegin at 7 wk, and at 8 wk the species is endothermic, that is, able to increase heat production in response to both cold and norepinephrine. The appearance of fur, first seen at the age of 6 wk and fully developed at 8 wk, coincides with the onset of endothermy.