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Full-Text Articles in Life Sciences
Ventilation Patterns In Red Kangaroos (Macropus Rufus Desmarest): Juveniles Work Harder Than Adults At Thermal Extremes, But Extract More Oxygen Per Breath At Thermoneutrality, Adam J. Munn, Terence J. Dawson, Shane K. Maloney
Ventilation Patterns In Red Kangaroos (Macropus Rufus Desmarest): Juveniles Work Harder Than Adults At Thermal Extremes, But Extract More Oxygen Per Breath At Thermoneutrality, Adam J. Munn, Terence J. Dawson, Shane K. Maloney
Faculty of Science - Papers (Archive)
Juvenile mortalities in large mammals are usually associated with environmental extremes, but the basis for this vulnerability is often unclear. Because of their high surface area to volume ratio, juveniles are expected to suffer greater thermal stresses relative to adults. Coping with thermal stress requires the ventilatory system to accommodate increases in oxygen demand and respiratory water loss at thermal extremes. Because juveniles are smaller than adults, these demands may set up different constraints on their ventilatory system. Using red kangaroos (Macropus rufus Desmarest), an arid zone species, we compared the ventilatory capabilities of juveniles and adults at thermoneutral (25 …
Forage Fibre Digestion, Rates Of Feed Passage And Gut Fill In Juvenile And Adult Red Kangaroos Macropus Rufus Desmarest: Why Body Size Matters, Adam J. Munn, Terence J. Dawson
Forage Fibre Digestion, Rates Of Feed Passage And Gut Fill In Juvenile And Adult Red Kangaroos Macropus Rufus Desmarest: Why Body Size Matters, Adam J. Munn, Terence J. Dawson
Faculty of Science - Papers (Archive)
Using red kangaroos Macropus rufus Desmarest, a large (>20 kg) marsupial herbivore, we compared the digestive capabilities of juveniles with those of mature, non-lactating females on high-quality forage (chopped lucerne Medicago sativa hay) of 43 +/- 1% neutral-detergent fibre (NDF) and poorer quality, high-fibre forage (chopped oaten Avena sativa hay) of 64 +/- 1% NDF. On chopped lucerne apparent dry matter (DM) digestibilities by young-at-foot (YAF) red kangaroos (an age that would normally be taking some milk from their mother), weaned juveniles and mature females were similar (55-59%). On chopped oaten hay apparent DM digestibility was lower in the …
Thermoregulation In Juvenile Red Kangaroos (Macropus Rufus) After Pouch Exit: Higher Metabolism And Evaporative Water Requirements, Adam J. Munn, Terence J. Dawson
Thermoregulation In Juvenile Red Kangaroos (Macropus Rufus) After Pouch Exit: Higher Metabolism And Evaporative Water Requirements, Adam J. Munn, Terence J. Dawson
Faculty of Science - Papers (Archive)
The population dynamics of red kangaroos (Macropus rufus) in the Australian arid zone is tightly linked with environmental factors, which partly operate via the survival of juvenile animals. A crucial stage is the young-at-foot (YAF) stage when kangaroos permanently exit the pouch. We have examined the thermal biology of YAF red kangaroos during ages from permanent pouch exit until weaning. Over a wide range of environmental temperatures (ambient temperature [T-a] -5 degrees to 45 degreesC), YAF red kangaroos had a mass-specific metabolism that was generally twice that of adults, considerably higher than would be expected for an adult marsupial of …
Thermoregulation By Kangaroos From Mesic And Arid Habitats: Influence Of Temperature On Routes Of Heat Loss In Eastern Grey Kangaroos (Macropus Giganteus) And Red Kangaroos (Macropus Rufus), Terence J. Dawson, Cyntina E. Blaney, Adam J. Munn, Andrew Krockenberger, Shane K. Maloney
Thermoregulation By Kangaroos From Mesic And Arid Habitats: Influence Of Temperature On Routes Of Heat Loss In Eastern Grey Kangaroos (Macropus Giganteus) And Red Kangaroos (Macropus Rufus), Terence J. Dawson, Cyntina E. Blaney, Adam J. Munn, Andrew Krockenberger, Shane K. Maloney
Faculty of Science - Papers (Archive)
We examined thermoregulation in red kangaroos (Macropus rufus) from deserts and in eastern grey kangaroos (Macropus giganteus) from mesic forests/woodlands. Desert kangaroos have complex evaporative heat loss mechanisms, but the relative importance of these mechanisms is unclear. Little is known of the abilities of grey kangaroos. Our detailed study of these kangaroos' thermoregulatory responses at air temperatures (T-a) From -5 degrees to 45 degrees C showed that, while some differences occur, their abilities are fundamentally similar. Both species show the basic marsupial characteristics of relatively low basal metabolism and body temperature (T-b). Within the thermoneutral zone, T-b was 36.3 degrees …
Ventilatory Accommodation Of Oxygen Demand And Respiratory Water Loss In Kangaroos From Mesic And Arid Environments, The Eastern Grey Kangaroo (Macropus Giganteus) And The Red Kangaroo (Macropus Rufus), Terence J. Dawson, Adam J. Munn, Cyntina E. Blaney, Andrew Krockenberger, Shane K. Maloney
Ventilatory Accommodation Of Oxygen Demand And Respiratory Water Loss In Kangaroos From Mesic And Arid Environments, The Eastern Grey Kangaroo (Macropus Giganteus) And The Red Kangaroo (Macropus Rufus), Terence J. Dawson, Adam J. Munn, Cyntina E. Blaney, Andrew Krockenberger, Shane K. Maloney
Faculty of Science - Papers (Archive)
We studied ventilation in kangaroos from mesic and arid environments, the eastern grey kangaroo (Macropus giganteus) and the red kangaroo (Macropus rufus), respectively, within the range of ambient temperatures (T-a) from -5 degrees to 45 degrees C. At thermoneutral temperatures (T-a = 25 degrees C), there were no differences between the species in respiratory frequency, tidal volume, total ventilation, or oxygen extraction. The ventilatory patterns of the kangaroos were markedly different from those predicted from the allometric equation derived for placentals. The kangaroos had low respiratory frequencies and higher tidal volumes, even when adjustment was made for their lower basal …