Development of thermoregulation in the sugar glider <i>Petaurus breviceps</i> (Marsupialia: Petauridae)

Holloway, Joanne C.; Geiser, Fritz

doi:10.1111/j.1469-7998.2000.tb00634.x

Cited by 19 publications

(10 citation statements)

References 32 publications

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“…The more labile T b of YAF red kangaroos over a range of T a are consistent with findings for many young mammals (Janssens et al 1997;Holloway and Geiser 2000). In the newborn marsupial, T b is unregulated and thermoregulation is not well developed until shortly before PPE (Hulbert 1988;Holloway and Geiser 2000).…”

Section: Discussionsupporting

confidence: 86%

“…2), is consistent with that seen in most young mammals (Brody 1945;Thompson et al 1987;Janssens et al 1997;Holloway and Geiser 2000). Overall, the YAF red kangaroos had double the metabolic intensity of adults.…”

Section: Discussionsupporting

confidence: 82%

“…In the newborn marsupial, T b is unregulated and thermoregulation is not well developed until shortly before PPE (Hulbert 1988;Holloway and Geiser 2000). Our results indicate that after PPE the T b 's of YAF red kangaroos are somewhat higher than that of adults, by around 0.6Њ-1.5ЊC (Fig.…”

Section: Discussionmentioning

confidence: 64%

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Thermoregulation in Juvenile Red Kangaroos (Macropus rufus) after Pouch Exit: Higher Metabolism and Evaporative Water Requirements

Munn¹,

Dawson²

2001

Physiological and Biochemical Zoology

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, T. J. (2001). Thermoregulation in juvenile red kangaroos (Macropus rufus) after pouch exit: higher metabolism and evaporative water requirements. Physiological and Biochemical Zoology, 74 (6), 917-927. Thermoregulation in juvenile red kangaroos (Macropus rufus) after pouch exit: higher metabolism and evaporative water requirements AbstractThe 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-atfoot (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 their body size. The total energy requirements of YAF red kangaroos were 60%-70% of those of adult females, which were three times their size. Over the same range in T-a, YAF red kangaroos also had total evaporative water losses equal to those of adult females. At the highest Ta (45 degreesC), differences were noted in patterns of dry heat loss (dry conductance) between YAF red kangaroos and adult females, which may partially explain the relatively high levels of evaporative cooling by YAF. By weaning age, young kangaroos showed little change in their basal energy and water requirements (at T-a 25 degreesC) but did show reduced mass-specific costs in terms of energy and water use at extremes of T-a (-5 degrees and 45 degreesC, respectively). In their arid environment, typified by unpredictable rainfall and extremes of T-a, young red kangaroos may need to remain close to water points, which, in turn, may restrict their ability to find the highquality forage needed to meet their high energy demands. ABSTRACTThe 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 ] Ϫ5Њ to 45ЊC), 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 their body size. The total energy requirements of YAF red kangaroos were 60%-70% of those of adult females, which were three times their size. Over the same range in T a , YAF red kangaroos also had total evaporative water losses equal to those of adult females. At the highest T a (45ЊC), differences were noted in patterns of dry heat loss (dry conductance) between YAF red kangaroos and adult femal...

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Section: Discussionsupporting

confidence: 86%

Section: Discussionsupporting

confidence: 82%

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Thermoregulation in Juvenile Red Kangaroos (Macropus rufus) after Pouch Exit: Higher Metabolism and Evaporative Water Requirements

Munn¹,

Dawson²

2001

Physiological and Biochemical Zoology

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“…Moreover, energy expenditure in sugar gliders may also be affected by their ability to use daily torpor. However, in captivity, sugar gliders are most reluctant to enter daily torpor and usually do so only after prolonged starvation (Galbraith 1977;Fleming 1980;Dawson and May 1984;Holloway 1998). Since free-ranging sugar gliders have never been observed in torpor, it could be argued that the species is able to survive in the wild by employing energy-saving strategies other than torpor under most circumstances.…”

Section: Introductionmentioning

confidence: 99%

Torpor and activity patterns in free-ranging sugar gliders Petaurus breviceps (Marsupialia)

2000

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Almost all studies on daily torpor in mammals have been conducted in the laboratory under constant environmental conditions. We investigated torpor and activity patterns in free-ranging sugar gliders (Petaurus breviceps, 100 g) using temperature telemetry and compared field data with published information obtained in the laboratory. Body and/or skin temperature and activity patterns of 12 sugar gliders were monitored from autumn to spring. Healthy sugar gliders were active between sunset and sunrise, but on cold or rainy nights activity was substantially reduced. Animals in poor condition occasionally foraged during the day. Eleven gliders were monitored for 8-171 days and all of these entered daily torpor. Torpor was observed on 103 days (17% of observation days), usually occurred on rainy or cold nights, and frequency of torpor changed with season. Torpor bouts lasted between 2 and 23 h (average 13 h) and the body temperature fell to a minimum of 10.4°C. Torpor was thus much deeper, longer and more frequent than in laboratory studies on the same species. Our study shows that cold or wet conditions curtail foraging in wild sugar gliders and that they employ daily torpor regularly during adverse weather. This suggests that minimisation of energy loss by the use of torpor in sugar gliders is pivotal for their survival in the wild.

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“…Therefore we cannot test whether juveniles differ from adults in relative stride length or frequency as a by-product of enhanced grasping musculature as in primates (Raichlen, 2005a;Raichlen, 2005b). Once out of the pouch, sugar gliders will 'ride' on the back of their mother or father, but this is an intermittent activity, and they are often left in the nest while the parents forage (Smith, 1971;Holloway and Geiser, 2000). By contrast, most primates cling fairly continuously to their mothers until they reach locomotor independence (Altmann, 2001;Ross, 2001).…”

Section: Prediction For Effect Of Age On Mean Support Numbermentioning

confidence: 99%

Kinematics of quadrupedal locomotion in sugar gliders (Petaurus breviceps): effects of age and substrate size

Shapiro

Young

2012

Journal of Experimental Biology

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SUMMARY Arboreal mammals face unique challenges to locomotor stability. This is particularly true with respect to juveniles, who must navigate substrates similar to those traversed by adults, despite a reduced body size and neuromuscular immaturity. Kinematic differences exhibited by juveniles and adults on a given arboreal substrate could therefore be due to differences in body size relative to substrate size, to differences in neuromuscular development, or to both. We tested the effects of relative body size and age on quadrupedal kinematics in a small arboreal marsupial (the sugar glider, Petaurus breviceps; body mass range of our sample 33-97 g). Juvenile and adult P. breviceps were filmed moving across a flat board and three poles 2.5, 1.0 and 0.5 cm in diameter. Sugar gliders (regardless of age or relative speed) responded to relative decreases in substrate diameter with kinematic adjustments that promote stability; they increased duty factor, increased the average number of supporting limbs during a stride, increased relative stride length and decreased relative stride frequency. Limb phase increased when moving from the flat board to the poles, but not among poles. Compared with adults, juveniles (regardless of relative body size or speed) used lower limb phases, more pronounced limb flexion, and enhanced stability with higher duty factors and a higher average number of supporting limbs during a stride. We conclude that although substrate variation in an arboreal environment presents similar challenges to all individuals, regardless of age or absolute body size, neuromuscular immaturity confers unique problems to growing animals, requiring kinematic compensation.

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Development of thermoregulation in the sugar glider Petaurus breviceps (Marsupialia: Petauridae)

Cited by 19 publications

References 32 publications

Thermoregulation in Juvenile Red Kangaroos (Macropus rufus) after Pouch Exit: Higher Metabolism and Evaporative Water Requirements

Thermoregulation in Juvenile Red Kangaroos (Macropus rufus) after Pouch Exit: Higher Metabolism and Evaporative Water Requirements

Torpor and activity patterns in free-ranging sugar gliders Petaurus breviceps (Marsupialia)

Kinematics of quadrupedal locomotion in sugar gliders (Petaurus breviceps): effects of age and substrate size

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