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Arthur Georges - One of the best experts on this subject based on the ideXlab platform.

  • Development of microsatellite markers in the Australasian snake‐necked turtle Chelodina rugusa and cross‐species amplification
    Molecular Ecology Resources, 2020
    Co-Authors: Erika Alacs, Arthur Georges, M J Hillyer, Nancy N Fitzsimmons, J M Hughes
    Abstract:

    Seventeen microsatellite loci were developed for the snake-necked turtle, Chelodina rugosa (Ogilby, 1890). Sixteen of the loci were polymorphic but three of these loci had null alleles. One locus displayed linkage disequilibrium. These 17 markers were tested for amplification in eight congeneric species with varying success; 98% amplification in Chelodina burrungandjii, 72% in C. canni, 38% in C. expansa, 58% in C. longicollis, 67% in C. mccordi, 73% in C. oblonga, 81% in C. parkeri, and 68% in C. pritchardi. These microsatellite markers will be useful for population assignment, gene flow, mating systems and hybridization studies in the genus Chelodina. Keyword: Australia, Chelidae, Chelonia, freshwater turtle, hybridization, wildlife management

  • Conservation implications of turtle declines in Australia's Murray River system
    Scientific Reports, 2019
    Co-Authors: J. U. Van Dyke, Rickyjohn Spencer, Michael B Thompson, Bruce C. Chessman, K. Howard, Arthur Georges
    Abstract:

    Conservation requires rapid action to be effective, which is often difficult because of funding limitations, political constraints, and limited data. Turtles are among the world’s most endangered vertebrate taxa, with almost half of 356 species threatened with extinction. In Australia’s Murray River, nest predation by invasive foxes (Vulpes vulpes) was predicted to drive turtle declines in the 1980s. We assessed populations of the broad-shelled turtle (Chelodina expansa), eastern long-necked turtle (C. longicollis), and Murray River turtle (Emydura macquarii) in the Murray River and some of its associated waterways. Our results suggest that the predicted decline is occurring. All three species are rare in the lower Murray River region, and were undetected in many locations in South Australia. Moreover, E. macquarii had considerable population aging almost everywhere, possibly due to comprehensive nest destruction by foxes. Chelodina longicollis also had population aging at some sites. Sustained low recruitment has potential to lead to collapses as turtles age, which is particularly worrying because it was predicted over 30 years ago and may have already occurred in South Australia. Our results show that turtle declines were not mitigated since that prediction. If the crash continues, a vertebrate guild responsible for considerable nutrient cycling in the aquatic ecosystem will disappear. Our results highlight a worst-case outcome when species declines are predicted, but insufficiently mitigated.

  • salinity tolerances of two australian freshwater turtles Chelodina expansa and emydura macquarii testudinata chelidae
    Conservation Physiology, 2016
    Co-Authors: Deborah S. Bower, David M Scheltinga, Simon Clulow, John Clulow, Craig E Franklin, Arthur Georges
    Abstract:

    Freshwater biota experience physiological challenges in regions affected by salinization, but often the effects on particular species are poorly understood. Freshwater turtles are of particular concern as they appear to have limited ability to cope with environmental conditions that are hyperosmotic to their body fluids. Here, we determined the physiological responses of two Australian freshwater chelid turtles, Emydura macquarii and Chelodina expansa, exposed to freshwater (0‰) and brackish water (15‰, representing a hyperosmotic environment). Brackish water is common in the Murray–Darling River Basin within the natural range of these species in Australia during periods of drought, yet it is unknown how well these species tolerate saline conditions. We hypothesized that these turtles would be unable to maintain homeostasis in the 15‰ water treatment and would suffer osmotic loss of water, increased ionic concentrations and a decrease in body mass. Results revealed that these turtles had elevated plasma concentrations of sodium, chloride, urea and uric acid in the plasma. Plasma ionic concentrations increased proportionally more in E. macquarii than in C. expansa. Individuals of both species reduced feeding in 15‰ water, indicating that behaviour may provide an additional means for freshwater turtles to limit ion/solute influx when in hyperosmotic environments. This osmoregulatory behaviour may allow for persistence of turtles in regions affected by salinization; however, growth rates and body condition may be affected in the long term. Although we demonstrate that these turtles have mechanisms to survive temporarily in saline waters, it is likely that sustained salinization of waterways will exceed their short- to medium-term capacity to survive increased salt levels, making salinization a potentially key threatening process for these freshwater reptiles.

  • significant genetic structure despite high vagility revealed through mitochondrial phylogeography of an australian freshwater turtle Chelodina longicollis
    Marine and Freshwater Research, 2015
    Co-Authors: K Hodges, Stephen C. Donnellan, Arthur Georges
    Abstract:

    Restriction to the freshwater environment plays a dominant role in the population genetic structure of freshwater fauna. In taxa with adaptations for terrestriality, however, the restrictions on dispersal imposed by drainage divides may be overcome. We investigate the mitochondrial phylogeographic structure of the eastern long-necked turtle (Chelodina longicollis), a widespread Australian freshwater obligate with strong overland dispersa\l capacity and specific adaptations to terrestriality. We predict that such characteristics make this freshwater species a strong candidate to test how life-history traits can drive gene flow and interbasin connectivity, overriding the constraining effects imposed by hydrological boundaries. Contrary to expectations, and similar to low-vagility freshwater vertebrates, we found two ancient mitochondrial haplogroups with clear east–west geographic partitioning either side of the Great Dividing Range. Each haplogroup is characterised by complex genetic structure, demographically stable subpopulations, and signals of isolation by distance. This pattern is overlaid with signatures of recent gene flow, likely facilitated by late Pleistocene and ongoing anthropogenic landscape change. We demonstrate that the divergent effects of landscape history can overwhelm the homogenising effects of life-history traits that connect populations, even in a highly vagile species.

  • Reptile bycatch in a pest-exclusion fence established for wildlife reintroductions
    Journal for Nature Conservation, 2014
    Co-Authors: Bruno O. Ferronato, Arthur Georges
    Abstract:

    Abstract Conservation fences have been used as a tool to stop threatening processes from acting against endangered wildlife, yet little is known of the impacts of fences on non-target native species. In this study, we intensively monitored a pest-exclusion fence for 16 months to assess impacts on a reptile community in south-eastern Australia. We registered 1052 reptile records of six species along the fence. Encounters and mortality were greatest for eastern long-necked turtles (Chelodina longicollis), whereas impacts on lizards (Tiliqua rugosa, Tiliqua scincoides, Pogona barbata, Egernia cunninghami) and snakes (Pseudonaja textilis) were more moderate. We recorded several Chelodina longicollis recaptures at the fence and many of these were later found dead at the fence, indicating persistent attempts to navigate past the fence. We conservatively estimate that the fence resulted in the death of 3.3% and disrupted movements of 20.9% of the turtle population within the enclosure. Movement disruption and high mortality were also observed for turtles attempting to enter the nature reserve, effectively isolating the reserve population from others in the wider landscape. Of 98 turtle mortalities, the most common cause of death was overheating, followed by predation, vehicular collision, and entanglement. Turtle interactions were clustered in areas with more wetlands and less urban development, and temporally correlated with high rainfall and solar radiation, and low temperature. Thus, managers could focus at times and locations to mitigate impacts on turtles. We believe the impact of fences on non-target species is a widespread and unrecognized threat, and suggest that future and on-going conservation fencing projects consider risks to non-target native species, and where possible, apply mitigation strategies that maintain natural movement corridors and minimize mortality risk.

Rickyjohn Spencer - One of the best experts on this subject based on the ideXlab platform.

  • Prey-switching does not protect a generalist turtle from bioenergetic consequences when its preferred food is scarce
    BMC Ecology, 2020
    Co-Authors: Kristen Petrov, Rickyjohn Spencer, Jessica Lewis, Natasha Malkiewicz, Claudia Keitel, James U Van Dyke
    Abstract:

    Background Optimal foraging theory explains how animals make foraging decisions based on the availability, nutritional content, and handling times of different food types. Generalists solve this problem by consuming a variety of food types, and alter their diets with relative ease. Specialists eat few food types, and may starve if those food types are not available. We integrated stable isotope analyses with previously-published stomach contents and environmental data to investigate how the foraging ecologies of three sympatric freshwater turtle species vary across four wetlands that differ in turbidity and primary producer abundance. Results We found that the generalist Emydura macquarii consumes a varied diet (but mostly filamentous green algae) when primary producers are available and water is clear, but switches to a more carnivorous diet when the water is turbid and primary producers are scarce, following the predictions of optimal foraging theory. In contrast, two more-specialized carnivorous species, Chelodina expansa and Chelodina longicollis , do not differ in diet across wetlands, and interspecific competition may increase where E. macquarii is carnivorous. When forced to be more carnivorous, E. macquarii exhibits higher rates of empty stomachs, and female turtles have reduced body condition, but neither Chelodina species are affected. Conclusions Our results provide support for optimal foraging theory, but also show that the ability to change diet does not protect the generalist from experiencing lower foraging success when its preferred food is rare, with direct consequences for their energy budgets. Our results have conservation implications because wetlands in the Murray–Darling river system are increasingly turbid and have low macrophyte abundance, and all three species are declining.

  • Prey-switching does not protect a generalist turtle from bioenergetic consequences when its preferred food is scarce.
    BMC Ecology, 2020
    Co-Authors: Kristen Petrov, Rickyjohn Spencer, Jessica Lewis, Natasha Malkiewicz, Claudia Keitel, James U Van Dyke
    Abstract:

    BACKGROUND: Optimal foraging theory explains how animals make foraging decisions based on the availability, nutritional content, and handling times of different food types. Generalists solve this problem by consuming a variety of food types, and alter their diets with relative ease. Specialists eat few food types, and may starve if those food types are not available. We integrated stable isotope analyses with previously-published stomach contents and environmental data to investigate how the foraging ecologies of three sympatric freshwater turtle species vary across four wetlands that differ in turbidity and primary producer abundance. RESULTS: We found that the generalist Emydura macquarii consumes a varied diet (but mostly filamentous green algae) when primary producers are available and water is clear, but switches to a more carnivorous diet when the water is turbid and primary producers are scarce, following the predictions of optimal foraging theory. In contrast, two more-specialized carnivorous species, Chelodina expansa and Chelodina longicollis, do not differ in diet across wetlands, and interspecific competition may increase where E. macquarii is carnivorous. When forced to be more carnivorous, E. macquarii exhibits higher rates of empty stomachs, and female turtles have reduced body condition, but neither Chelodina species are affected. CONCLUSIONS: Our results provide support for optimal foraging theory, but also show that the ability to change diet does not protect the generalist from experiencing lower foraging success when its preferred food is rare, with direct consequences for their energy budgets. Our results have conservation implications because wetlands in the Murray-Darling river system are increasingly turbid and have low macrophyte abundance, and all three species are declining.

  • Conservation implications of turtle declines in Australia's Murray River system
    Scientific Reports, 2019
    Co-Authors: J. U. Van Dyke, Rickyjohn Spencer, Michael B Thompson, Bruce C. Chessman, K. Howard, Arthur Georges
    Abstract:

    Conservation requires rapid action to be effective, which is often difficult because of funding limitations, political constraints, and limited data. Turtles are among the world’s most endangered vertebrate taxa, with almost half of 356 species threatened with extinction. In Australia’s Murray River, nest predation by invasive foxes (Vulpes vulpes) was predicted to drive turtle declines in the 1980s. We assessed populations of the broad-shelled turtle (Chelodina expansa), eastern long-necked turtle (C. longicollis), and Murray River turtle (Emydura macquarii) in the Murray River and some of its associated waterways. Our results suggest that the predicted decline is occurring. All three species are rare in the lower Murray River region, and were undetected in many locations in South Australia. Moreover, E. macquarii had considerable population aging almost everywhere, possibly due to comprehensive nest destruction by foxes. Chelodina longicollis also had population aging at some sites. Sustained low recruitment has potential to lead to collapses as turtles age, which is particularly worrying because it was predicted over 30 years ago and may have already occurred in South Australia. Our results show that turtle declines were not mitigated since that prediction. If the crash continues, a vertebrate guild responsible for considerable nutrient cycling in the aquatic ecosystem will disappear. Our results highlight a worst-case outcome when species declines are predicted, but insufficiently mitigated.

  • road mortality of the eastern long necked turtle Chelodina longicollis along the murray river australia an assessment using citizen science
    Australian Journal of Zoology, 2018
    Co-Authors: Claudia Santori, Rickyjohn Spencer, James U Van Dyke, Michael B Thompson
    Abstract:

    Turtles face a variety of threats (e.g. habitat destruction, introduced predators) that are pushing many species towards extinction. Vehicle collisions are one of the main causes of mortality of adult freshwater turtles. To conceptualise the level of threat that roads pose to Australians turtles, we analysed data gathered through the citizen science project TurtleSAT along the Murray River. We recorded 124 occurrences of turtle road mortality, which included all three local species (Chelodina expansa, Chelodina longicollis, and Emydura macquarii). Chelodina longicollis was the most commonly reported species killed on roads. We found that rain and time of year affect the likelihood of C. longicollis being killed on roads: increased turtle mortality is associated with rain events and is highest during the month of November, which coincides with their nesting season. Chelodina longicollis was most likely to be killed on the Hume Highway and roads around major urban centres; therefore, we recommend that governing bodies focus management practices and increase awareness at these locations. The degree of road mortality that we detected in this study requires mitigation, as it may contribute to the decline of C. longicollis along the Murray River.

  • Food abundance and diet variation in freshwater turtles from the mid-Murray River, Australia
    Australian Journal of Zoology, 2018
    Co-Authors: Kristen Petrov, James U Van Dyke, Jessica Lewis, Natasha Malkiewicz, Rickyjohn Spencer
    Abstract:

    Consumers usually respond to variations in prey availability by altering their foraging strategies. Generalist consumers forage on a diversity of resources and have greater potential to ‘switch’ their diet in response to fluctuations in prey availability, in comparison to specialist consumers. We aimed to determine how the diets of two specialist species (the eastern long-necked turtle (Chelodina longicollis) and the broad-shelled turtle (Chelodina expansa) and the more generalist Murray River short-necked turtle (Emydura macquarii) respond to variation in habitat and prey availability. We trapped and stomach-flushed turtles, and compared their diets along with environmental variables (turbidity, macrophyte and filamentous green algae cover, and aquatic invertebrate diversity and abundance) at four wetlands in north-central Victoria. Diets of E. macquarii differed from those of both Chelodina species, which overlapped, across all four sites. However, samples sizes for the two Chelodina species were too small to compare among-wetland variation in diet. Dietary composition of E. macquarii was variable but did not differ statistically among sites. Emydura macquarii preferentially selected filamentous green algae at three of the four sites. Where filamentous green algae were rare, total food bolus volume was reduced and E. macquarii only partially replaced it with other food items, including other vegetation, wood, and animal prey. Many turtles at these sites also had empty stomachs. Thus, filamentous green algae may be a limiting food for E. macquarii. Although E. macquarii has previously been described as a generalist, it appears to have limited ability to replace filamentous green algae with other food items when filamentous green algae are rare.

David T. Booth - One of the best experts on this subject based on the ideXlab platform.

Keith A Christian - One of the best experts on this subject based on the ideXlab platform.

  • notes on Chelodina mccordi timorensis biology harvest current threats and community perceptions in the lake iralalaro region timor leste
    Chelonian Conservation and Biology, 2016
    Co-Authors: Carla C Eisemberg, Bertanizo G Costa, Elda Guterres, Stephen J Reynolds, Keith A Christian
    Abstract:

    Abstract The long-necked turtle Chelodina mccordi is considered Critically Endangered under IUCN Red List criteria. In Timor-Leste, the subspecies Chelodina mccordi timorensis is restricted to a small area of lacustrine habitat near the eastern tip of Timor around Lake Iralalaro in the Lautem District. We collected information on C. m. timorensis biology and harvest and assessed current threats and community perceptions. Data were collected during 2 surveys (February and July 2014) around Lake Iralalaro in Nino Konis Santana National Park. Threats were identified by direct observation, and local perceptions were recorded during expert interviews. Human harvest is the main threat in the area. Animals are captured using fishing line, are located using a bamboo stick in shallow water to probe the mud, or are captured by hand at the edge of the lake or under dry grass. Turtles are captured mainly during the dry season (April to October). Most experts identified C. m. timorensis under 2 different names accordi...

  • underwater nesting by the australian freshwater turtle Chelodina rugosa effect of prolonged immersion and eggshell thickness on incubation period egg survivorship and hatchling size
    Canadian Journal of Zoology, 1998
    Co-Authors: Rod Kennett, Keith A Christian, Gavin S Bedford
    Abstract:

    The northern long-necked turtle, Chelodina rugosa, occupies seasonally ephemeral freshwater wetlands in thewet–dry tropics of northern Australia. The species has a highly unusual nesting strategy in that nesting takes place under waterwhen wetland habitats are flooded. Embryonic development proceeds when floodwaters recede during the annual dry seasonand hatchling emergence coincides with the start of the following wet season. This study examined the influence of duration ofimmersion of eggs on hatchling size and hatching success under laboratory conditions. Prolonged immersion of eggs in waterresults in smaller hatchlings and shorter incubation times, but does not increase egg mortality during incubation. Leaching ofcalcium from the eggshell, resulting in reduced availability of calcium to the developing embryo, may explain the smallerhatchlings and shorter incubation period. Hatchlings from thin-shelled eggs, in which shell formation was incomplete, weresmaller and hatched sooner, indicating that the eggshell plays a role in determining hatchling size and incubation period.Thin-shelled and normal eggs had equivalent egg survivorship, indicating that the eggshell is unimportant in egg survivalduring immersion.

  • osmotic balance in the eggs of the turtle Chelodina rugosa during developmental arrest under water
    Physiological and Biochemical Zoology, 1997
    Co-Authors: Roger S Seymour, Rod Kennett, Keith A Christian
    Abstract:

    The tropical Australian turtle Chelodina rugosa normally lays its hard-shelled eggs in mud, under shallow freshwater, during the monsoon season. The eggs undergo developmental arrest until the water recedes and oxygen is able to diffuse into the embryo. This period of arrest can exceed 12 wk without embryonic mortality. To understand how the eggs avoid osmotic absorption of water leading to shell rupture and embryonic death, this study investigates the solute concentrations and volumes of the albumen and yolk compartments during submergence in distilled water. The albumen loses considerable sodium through the shell, particularly during the first week, and its osmotic concentration drops from 234 mmol/kg at laying to about 23 mmol/kg. Meanwhile, water from the albumen slowly moves through the vitelline membrane into the yolk compartment, which enlarges at a constant rate until it approaches the inside of the shell at about 22 wk. Osmotic uptake dilutes yolk solutes, decreasing the osmotic concentration fro...

  • metabolic depression in estivating long neck turtles Chelodina rugosa
    Physiological and Biochemical Zoology, 1994
    Co-Authors: Rod Kennett, Keith A Christian
    Abstract:

    Long-neck turtles, Chelodina rugosa, inhabit seasonally ephemeral water holes on the coastal floodplains of the wet-dry tropics of Australia. Late in the annual dry season, the turtles bury themselves in the drying mud and estivate for as long as 4-5 mo until the wet season rains begin. We measured the oxygen consumption of five turtles that were induced to estivate in containers of mud at 30° C. This was typical of soil temperatures measured in natural estivation sites. The metabolic measurements of estivating turtles were compared to the standard metabolic rates (SMRs) at 30° C of these five postestivation turtles after they had spent 36 h in water and to the SMRs of 10 preestivation turtles. There was no difference between the pre- and postestivation SMRs, but the metabolic rates of estivating turtles decreased over about 2 wk to 28% of the SMR. This was not a response to starvation, because postestivation turtles were not fed. This metabolic depression conserves energy and, presumably, water during es...

Rod Kennett - One of the best experts on this subject based on the ideXlab platform.

  • Chelodina burrungandjii thomson kenneth and georges 2000 sandstone snake necked turtle
    Chelonian Research Monographs, 2011
    Co-Authors: Scott Thomson, Erika Alacs, Nancy N Fitzsimmons, Rod Kennett, Phillipa Featherston, Arthur Georges
    Abstract:

    056.1 Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group A.G.J. Rhodin, P.C.H. Pritchard, P.P. van Dijk, R.A. Saumure, K.A. Buhlmann, J.B. Iverson, and R.A. Mittermeier, Eds. Chelonian Research Monographs (ISSN 1088-7105) No. 5, doi:10.3854/crm.5.056.burrungandjii.v1.2011 © 2011 by Chelonian Research Foundation • Published 31 December 2011

  • a new species of long necked turtle chelidae Chelodina from the sandstone plateau of arnhem land northern australia
    Chelonian Conservation and Biology, 2000
    Co-Authors: Scott Thomson, Rod Kennett, Arthur Georges
    Abstract:

    A new species of long-necked freshwater turtle of the family Chelidae is described from the Arnhem Land Plateau in the Northern Territory of Australia. The taxon is within the Chelodina expansa group of species and is the smallest member of that group. First collected by scientists some 20 years ago, research on the species has been hampered by its isolation – it is restricted to sparsely inhabited, rugged sandstone country of tropical northern Australia. It can be diagnosed by its broad, shortened and flattened skull, by the possession of a contiguous neural series and by the contact of the vomer and the pterygoids. It is clearly distinct from Chelodina rugosa in a canonical discriminant analysis. Preliminary data on natural history are also presented. Males examined in October-November had enlarged vascularised testes and epididymes distended with sperm. Females examined at the same time had regressed corpora lutea and atretic follicles from the previous nesting season, presumably in the immediately preceding dry season. The diet is primarily fish and shrimp, but unlike other Chelodina which are all obligate carnivores, this species appears to feed on both plant and animal material. The turtle is well known to Aboriginal people of the region who collect it for food, and they report that it consumes leaves and fruits of aquatic and riparian vegetation and reproduces in the dry season.

  • underwater nesting by the australian freshwater turtle Chelodina rugosa effect of prolonged immersion and eggshell thickness on incubation period egg survivorship and hatchling size
    Canadian Journal of Zoology, 1998
    Co-Authors: Rod Kennett, Keith A Christian, Gavin S Bedford
    Abstract:

    The northern long-necked turtle, Chelodina rugosa, occupies seasonally ephemeral freshwater wetlands in thewet–dry tropics of northern Australia. The species has a highly unusual nesting strategy in that nesting takes place under waterwhen wetland habitats are flooded. Embryonic development proceeds when floodwaters recede during the annual dry seasonand hatchling emergence coincides with the start of the following wet season. This study examined the influence of duration ofimmersion of eggs on hatchling size and hatching success under laboratory conditions. Prolonged immersion of eggs in waterresults in smaller hatchlings and shorter incubation times, but does not increase egg mortality during incubation. Leaching ofcalcium from the eggshell, resulting in reduced availability of calcium to the developing embryo, may explain the smallerhatchlings and shorter incubation period. Hatchlings from thin-shelled eggs, in which shell formation was incomplete, weresmaller and hatched sooner, indicating that the eggshell plays a role in determining hatchling size and incubation period.Thin-shelled and normal eggs had equivalent egg survivorship, indicating that the eggshell is unimportant in egg survivalduring immersion.

  • osmotic balance in the eggs of the turtle Chelodina rugosa during developmental arrest under water
    Physiological and Biochemical Zoology, 1997
    Co-Authors: Roger S Seymour, Rod Kennett, Keith A Christian
    Abstract:

    The tropical Australian turtle Chelodina rugosa normally lays its hard-shelled eggs in mud, under shallow freshwater, during the monsoon season. The eggs undergo developmental arrest until the water recedes and oxygen is able to diffuse into the embryo. This period of arrest can exceed 12 wk without embryonic mortality. To understand how the eggs avoid osmotic absorption of water leading to shell rupture and embryonic death, this study investigates the solute concentrations and volumes of the albumen and yolk compartments during submergence in distilled water. The albumen loses considerable sodium through the shell, particularly during the first week, and its osmotic concentration drops from 234 mmol/kg at laying to about 23 mmol/kg. Meanwhile, water from the albumen slowly moves through the vitelline membrane into the yolk compartment, which enlarges at a constant rate until it approaches the inside of the shell at about 22 wk. Osmotic uptake dilutes yolk solutes, decreasing the osmotic concentration fro...

  • metabolic depression in estivating long neck turtles Chelodina rugosa
    Physiological and Biochemical Zoology, 1994
    Co-Authors: Rod Kennett, Keith A Christian
    Abstract:

    Long-neck turtles, Chelodina rugosa, inhabit seasonally ephemeral water holes on the coastal floodplains of the wet-dry tropics of Australia. Late in the annual dry season, the turtles bury themselves in the drying mud and estivate for as long as 4-5 mo until the wet season rains begin. We measured the oxygen consumption of five turtles that were induced to estivate in containers of mud at 30° C. This was typical of soil temperatures measured in natural estivation sites. The metabolic measurements of estivating turtles were compared to the standard metabolic rates (SMRs) at 30° C of these five postestivation turtles after they had spent 36 h in water and to the SMRs of 10 preestivation turtles. There was no difference between the pre- and postestivation SMRs, but the metabolic rates of estivating turtles decreased over about 2 wk to 28% of the SMR. This was not a response to starvation, because postestivation turtles were not fed. This metabolic depression conserves energy and, presumably, water during es...