Thermal Biology of the Australian Forest Dragon, Hypsilurus spinipes (Agamidae)

Rummery, Catherine; Shine, Richard; Houston, Darryl; Thompson, Michael B.

doi:10.2307/1447030

Cited by 26 publications

(24 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, during the dry season in northern Australia, one species of large, deciduous mangrove tree (Xylocarpus mekongensis) loses its leaves (Brock 2001), creating numerous larger sun patches that would provide easier access to warmer microclimates. An example of a lizard from northern Australia that does not actively seek sun patches is Hypsilurus spinipes, an agamid that lives in deeply shaded rain forest and is a complete thermoconformer (Rummery et al 1995). It is clear from the temperature patterns in Figure 1B that V. indicus is not a complete thermoconformer, but the extent to which the effort required to thermoregulate to higher T b 's in the shady mangrove forest influences the low daytime T b 's of this species is not known.…”

Section: Thermoregulationmentioning

confidence: 99%

“…The extent to which species and individuals respond to these thermally variable conditions varies from complete thermoconformity, usually in places where temperatures are relatively high and constant (Lee 1980;Rummery et al 1995), to the maintenance of high and relatively stable body temperatures (T b 's) using complex thermoregulatory behaviors (Diaz 1992;Villavicencio et al 2007). In highly seasonal climates, many species use a combination of behavioral and physiological mechanisms to conserve energy when food and water are limited (Stanner and Mendelssohn 1991;Christian and Green 1994;Pianka 1994; Thompson et al 1998;Heger 2000;Guarino et al 2002).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Physiological Ecology of the Mangrove‐Dwelling Varanid Varanus indicus

Smith¹,

Christian²,

Green³

2008

Physiological and Biochemical Zoology

View full text Add to dashboard Cite

Some species of terrestrial lizards in wet-dry tropical climates reduce their body temperatures (T(b)'s) and activity and lower their metabolic rates during the dry season when food and water resources are scarce. However, semiaquatic lizards have access to water and presumably food throughout the year, so it is possible that they will not have the seasonal response seen in terrestrial species. We studied the thermal biology, energetics, and water flux of Varanus indicus, a semiaquatic, mangrove-dwelling varanid in tropical northern Australia. Although V. indicus remained active all year, they reduced their activity in the dry season, but not to the extent of terrestrial varanids. Varanus indicus field metabolic rates decreased by 38% in the dry season mostly as a result of the reduction in activity. Although food and water depletion are the driving forces behind decreases in dry season T(b) selection and energetics for many varanids, V. indicus appears not to be subject to these pressures to the same extent. Thermoregulatory indices indicate that V. indicus actively thermoregulate in the wet and dry seasons, but they do not fully exploit the available thermal resources. These lizards are unusual among varanid lizards in that their midday T(b)'s are relatively low (about 31 degrees C) despite the availability of thermal resources that would allow them to attain substantially higher T(b)'s.

show abstract

Section: Thermoregulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Physiological Ecology of the Mangrove‐Dwelling Varanid Varanus indicus

Smith¹,

Christian²,

Green³

2008

Physiological and Biochemical Zoology

View full text Add to dashboard Cite

show abstract

“…At the very least, the prolonged immobility required by a camouflaged ambush predator may preclude shuttling between thermally 'optimal' habitats, and hence force it to be a thermoconformer (e.g. Secor & Nagy 1994;Rummery et al 1995). The interplay between thermal ecology and foraging biology is likely to be important for taxa that forage in other ways as well.…”

Section: Extrapolation To the Fieldmentioning

confidence: 99%

Thermal influences on foraging ability: body size, posture and cooling rate of an ambush predator, the python Morelia spilota

Ayers

Shine

1997

Functional Ecology

View full text Add to dashboard Cite

Summary 1.The interface between thermal biology and foraging mode has attracted little scientific attention, but may be crucially important to the biology of ectothermic predators. Slip & Shine (1988c) suggested that the ability of large heavy-bodied snakes to ambush nocturnally active mammals relied on the snakes' control of cooling rates through their thermal inertia (via body size and postural adjustments) and microhabitat selection. 2. We tested assumptions underlying this hypothesis, using Diamond Pythons (Morelia s. spilota) from southeastern New South Wales. Our laboratory studies confirmed that larger body sizes and coiled postures significantly retarded cooling rates, and that body temperature affected the snakes' ability to detect potential prey items. 3. The magnitude of these effects on cooling rates was great enough to extend the time period substantially over which an adult Diamond Python, lying in ambush in a suitable microhabitat, would be able to detect and capture nocturnally active prey. For example, the times taken for pythons to reach thermal equilibration under our experimental conditions (cooling from 33 to 12°C) were < 1 h for hatchling pythons regardless of posture, 1 h for outstretched juveniles, 2 h for coiled juveniles and outstretched adults, and almost 8 h for coiled adults. 4. The high rates of cooling of juvenile pythons, even when they are tightly coiled, may force them to rely upon diurnally active prey rather than crepuscular or nocturnal species.

show abstract

“…Conversely, although P. barbata was previously reported to spend the winter burrowed underground (Ehmann, 1992), we observed that this was the exception and that adults spent much of their time, including over winter, in the canopy or on the trunks of the tallest trees in the woodlands. This has also been observed for the frill-neck lizard Chlamydosaurus kingii (Christian and Bedford, 1995;Griffiths and Christian, 1996) and the angleheaded dragon Hypsilurus spinipes (Rummery et al, 1995). Having a relatively more robust body size as adults, compared to the grounddwelling juveniles, would maximise the adults' chances of evading predation (Herrel et al, 2002), since the predators most frequently encountered in the canopy would be predatory birds.…”

Section: Discussionmentioning

confidence: 61%