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Mohanty NP, Wagener C, Herrel A, Thaker M. The ecology of sleep in non-avian reptiles. Biol Rev Camb Philos Soc 2021; 97:505-526. [PMID: 34708504 DOI: 10.1111/brv.12808] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 10/10/2021] [Accepted: 10/18/2021] [Indexed: 01/10/2023]
Abstract
Sleep is ubiquitous in the animal kingdom and yet displays considerable variation in its extent and form in the wild. Ecological factors, such as predation, competition, and microclimate, therefore are likely to play a strong role in shaping characteristics of sleep. Despite the potential for ecological factors to influence various aspects of sleep, the ecological context of sleep in non-avian reptiles remains understudied and without systematic direction. In this review, we examine multiple aspects of reptilian sleep, including (i) habitat selection (sleep sites and their spatio-temporal distribution), (ii) individual-level traits, such as behaviour (sleep postures), morphology (limb morphometrics and body colour), and physiology (sleep architecture), as well as (iii) inter-individual interactions (intra- and inter-specific). Throughout, we discuss the evidence of predation, competition, and thermoregulation in influencing sleep traits and the possible evolutionary consequences of these sleep traits for reptile sociality, morphological specialisation, and habitat partitioning. We also review the ways in which sleep ecology interacts with urbanisation, biological invasions, and climate change. Overall, we not only provide a systematic evaluation of the conceptual and taxonomic biases in the existing literature on reptilian sleep, but also use this opportunity to organise the various ecological hypotheses for sleep characteristics. By highlighting the gaps and providing a prospectus of research directions, our review sets the stage for understanding sleep ecology in the natural world.
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Affiliation(s)
- Nitya P Mohanty
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, 560 012, India
| | - Carla Wagener
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, Western Cape, 7600, South Africa
| | - Anthony Herrel
- Département Adaptations du Vivant, MECADEV UMR7179 CNRS/MNHN, Paris, France
| | - Maria Thaker
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, 560 012, India
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2
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Veatch EG, Ringen EJ, Kilgore MB, Jatmiko. Using niche construction theory to generate testable foraging hypotheses at Liang Bua. Evol Anthropol 2021; 30:8-16. [PMID: 33529426 DOI: 10.1002/evan.21884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 10/15/2020] [Accepted: 01/06/2021] [Indexed: 11/09/2022]
Abstract
Niche construction theory (NCT) has emerged as a promising theoretical tool for interpreting zooarchaeological material. However, its juxtaposition against more established frameworks like optimal foraging theory (OFT) has raised important criticism around the testability of NCT for interpreting hominin foraging behavior. Here, we present an optimization foraging model with NCT features designed to consider the destructive realities of the archaeological record after providing a brief review of OFT and NCT. Our model was designed to consider a foragers decision to exploit an environment given predation risk, mortality, and payoff ratios between different ecologies, like more-open or more-forested environments. We then discuss how the model can be used with zooarchaeological data for inferring environmental exploitation by a primitive hominin, Homo floresiensis, from the island of Flores in Southeast Asia. Our example demonstrates that NCT can be used in combination with OFT principles to generate testable foraging hypotheses suitable for zooarchaeological research.
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Affiliation(s)
- Elizabeth G Veatch
- Department of Anthropology, Emory University, Atlanta, Georgia, USA.,Department of Anthropology, Yale University, New Haven, Connecticut, USA
| | - Erik J Ringen
- Department of Anthropology, Emory University, Atlanta, Georgia, USA
| | - Megan B Kilgore
- Department of Anthropology, Emory University, Atlanta, Georgia, USA
| | - Jatmiko
- Pusat Penelitian Arkeologi Nasional, Jakarta, Indonesia
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3
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Lovelace DM, Hartman SA, Mathewson PD, Linzmeier BJ, Porter WP. Modeling Dragons: Using linked mechanistic physiological and microclimate models to explore environmental, physiological, and morphological constraints on the early evolution of dinosaurs. PLoS One 2020; 15:e0223872. [PMID: 32469936 PMCID: PMC7259893 DOI: 10.1371/journal.pone.0223872] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 05/12/2020] [Indexed: 11/29/2022] Open
Abstract
We employed the widely-tested biophysiological modeling software, Niche Mapper™ to investigate the metabolic function of the Late Triassic dinosaurs Plateosaurus and Coelophysis during global greenhouse conditions. We tested a variety of assumptions about resting metabolic rate, each evaluated within six microclimate models that bound paleoenvironmental conditions at 12° N paleolatitude, as determined by sedimentological and isotopic proxies for climate within the Chinle Formation of the southwestern United States. Sensitivity testing of metabolic variables and simulated “metabolic chamber” analyses support elevated “ratite-like” metabolic rates and intermediate “monotreme-like” core temperature ranges in these species of early saurischian dinosaur. Our results suggest small theropods may have needed partial to full epidermal insulation in temperate environments, while fully grown prosauropods would have likely been heat stressed in open, hot environments and should have been restricted to cooler microclimates such as dense forests or higher latitudes and elevations. This is in agreement with the Late Triassic fossil record and may have contributed to the latitudinal gap in the Triassic prosauropod record.
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Affiliation(s)
- David M. Lovelace
- University of Wisconsin Geology Museum, Department of Geosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (DL); (WP)
| | - Scott A. Hartman
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Paul D. Mathewson
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Benjamin J. Linzmeier
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Warren P. Porter
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (DL); (WP)
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4
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Rezende EL, Bacigalupe LD, Nespolo RF, Bozinovic F. Shrinking dinosaurs and the evolution of endothermy in birds. SCIENCE ADVANCES 2020; 6:eaaw4486. [PMID: 31911937 PMCID: PMC6938711 DOI: 10.1126/sciadv.aaw4486] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 11/04/2019] [Indexed: 05/30/2023]
Abstract
The evolution of endothermy represents a major transition in vertebrate history, yet how and why endothermy evolved in birds and mammals remains controversial. Here, we combine a heat transfer model with theropod body size data to reconstruct the evolution of metabolic rates along the bird stem lineage. Results suggest that a reduction in size constitutes the path of least resistance for endothermy to evolve, maximizing thermal niche expansion while obviating the costs of elevated energy requirements. In this scenario, metabolism would have increased with the miniaturization observed in the Early-Middle Jurassic (~180 to 170 million years ago), resulting in a gradient of metabolic levels in the theropod phylogeny. Whereas basal theropods would exhibit lower metabolic rates, more recent nonavian lineages were likely decent thermoregulators with elevated metabolism. These analyses provide a tentative temporal sequence of the key evolutionary transitions that resulted in the emergence of small, endothermic, feathered flying dinosaurs.
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Affiliation(s)
- Enrico L. Rezende
- Center of Applied Ecology and Sustainability (CAPES), Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 6513677, Chile
| | - Leonardo D. Bacigalupe
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, Valdivia 5090000, Chile
| | - Roberto F. Nespolo
- Center of Applied Ecology and Sustainability (CAPES), Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 6513677, Chile
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, Valdivia 5090000, Chile
- Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Francisco Bozinovic
- Center of Applied Ecology and Sustainability (CAPES), Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 6513677, Chile
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5
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Bourke JM, Porter WR, Witmer LM. Convoluted nasal passages function as efficient heat exchangers in ankylosaurs (Dinosauria: Ornithischia: Thyreophora). PLoS One 2018; 13:e0207381. [PMID: 30566469 PMCID: PMC6300222 DOI: 10.1371/journal.pone.0207381] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 10/30/2018] [Indexed: 11/18/2022] Open
Abstract
Convoluted nasal passages are an enigmatic hallmark of Ankylosauria. Previous research suggested that these convoluted nasal passages functioned as heat exchangers analogous to the respiratory turbinates of mammals and birds. We tested this hypothesis by performing a computational fluid dynamic analysis on the nasal passages of two ankylosaurs: Panoplosaurus mirus and Euoplocephalus tutus. Our models predicted that Panoplosaurus and Euoplocephalus would have required 833 and 1568 thermal calories, respectively, to warm a single breath of air by 20°C. Heat recovery during exhalation resulted in energy savings of 65% for Panoplosaurus and 84% for Euoplocephalus. Our results fell well within the range of values for heat and water savings observed in extant terrestrial amniotes. We further tested alternate airway reconstructions that removed nasal passage convolutions or reduced nasal vestibule length. Our results revealed that the extensive elaboration observed in the nasal vestibules of ankylosaurs was a viable alternative to respiratory turbinates with regards to air conditioning. Of the two dinosaurs tested, Euoplocephalus repeatedly exhibited a more efficient nasal passage than Panoplosaurus. We suggest that the higher heat loads associated with the larger body mass of Euoplocephalus necessitated these more efficient nasal passages. Our findings further indicate that the evolution of complicated airways in dinosaurs may have been driven by the thermal requirements of maintaining cerebral thermal homeostasis.
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Affiliation(s)
- Jason M. Bourke
- Department of Biological Sciences, Ohio University, Athens, Ohio, United States of America
- * E-mail:
| | - Wm. Ruger Porter
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
| | - Lawrence M. Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
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6
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Myhrvold NP. Response to formal comment on Myhrvold (2016) submitted by Griebeler and Werner (2017). PLoS One 2018; 13:e0192912. [PMID: 29489880 PMCID: PMC5831047 DOI: 10.1371/journal.pone.0192912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/20/2018] [Indexed: 11/19/2022] Open
Abstract
Griebeler and Werner offer a formal comment on Myhrvold, 2016 defending the conclusions of Werner and Griebeler, 2014. Although the comment criticizes several aspects of methodology in Myhrvold, 2016, all three papers concur on a key conclusion: the metabolism of extant endotherms and ectotherms cannot be reliably classified using growth-rate allometry, because the growth rates of extant endotherms and ectotherms overlap. A key point of disagreement is that the 2014 paper concluded that despite this general case, one can nevertheless classify dinosaurs as ectotherms from their growth rate allometry. The 2014 conclusion is based on two factors: the assertion (made without any supporting arguments) that the comparison with dinosaurs must be restricted only to extant sauropsids, ignoring other vertebrate groups, and that extant sauropsid endotherm and ectotherm growth rates in a data set studied in the 2014 work do not overlap. The Griebeler and Werner formal comment presents their first arguments in support of the restriction proposition. In this response I show that this restriction is unsupported by established principles of phylogenetic comparison. In addition, I show that the data set studied in their 2014 work does show overlap, and that this is visible in one of its figures. I explain how either point effectively invalidates the conclusion of their 2014 paper. I also address the other methodological criticisms of Myhrvold 2016, and find them unsupported.
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7
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Falcón W, Baxter RP, Furrer S, Bauert M, Hatt J, Schaepman‐Strub G, Ozgul A, Bunbury N, Clauss M, Hansen DM. Patterns of activity and body temperature of Aldabra giant tortoises in relation to environmental temperature. Ecol Evol 2018; 8:2108-2121. [PMID: 29468029 PMCID: PMC5817133 DOI: 10.1002/ece3.3766] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 10/19/2017] [Accepted: 12/06/2017] [Indexed: 11/25/2022] Open
Abstract
We studied the temperature relations of wild and zoo Aldabra giant tortoises (Aldabrachelys gigantea) focusing on (1) the relationship between environmental temperature and tortoise activity patterns (n = 8 wild individuals) and (2) on tortoise body temperature fluctuations, including how their core and external body temperatures vary in relation to different environmental temperature ranges (seasons; n = 4 wild and n = 5 zoo individuals). In addition, we surveyed the literature to review the effect of body mass on core body temperature range in relation to environmental temperature in the Testudinidae. Diurnal activity of tortoises was bimodally distributed and influenced by environmental temperature and season. The mean air temperature at which activity is maximized was 27.9°C, with a range of 25.8-31.7°C. Furthermore, air temperature explained changes in the core body temperature better than did mass, and only during the coldest trial, did tortoises with higher mass show more stable temperatures. Our results, together with the overall Testudinidae overview, suggest that, once variation in environmental temperature has been taken into account, there is little effect of mass on the temperature stability of tortoises. Moreover, the presence of thermal inertia in an individual tortoise depends on the environmental temperatures, and we found no evidence for inertial homeothermy. Finally, patterns of core and external body temperatures in comparison with environmental temperatures suggest that Aldabra giant tortoises act as mixed conformer-regulators. Our study provides a baseline to manage the thermal environment of wild and rewilded populations of an important island ecosystem engineer species in an era of climate change.
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Affiliation(s)
- Wilfredo Falcón
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
| | - Rich P. Baxter
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
| | | | | | - Jean‐Michel Hatt
- Clinic for Zoo Animals, Exotic Pets and WildlifeVetsuisse FacultyUniversity of ZurichZurichSwitzerland
| | - Gabriela Schaepman‐Strub
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
| | - Nancy Bunbury
- Seychelles Islands FoundationPO Box 853, MaheSeychelles
| | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and WildlifeVetsuisse FacultyUniversity of ZurichZurichSwitzerland
| | - Dennis M. Hansen
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
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8
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Rey K, Amiot R, Fourel F, Abdala F, Fluteau F, Jalil NE, Liu J, Rubidge BS, Smith RM, Steyer JS, Viglietti PA, Wang X, Lécuyer C. Oxygen isotopes suggest elevated thermometabolism within multiple Permo-Triassic therapsid clades. eLife 2017; 6. [PMID: 28716184 PMCID: PMC5515572 DOI: 10.7554/elife.28589] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 06/20/2017] [Indexed: 01/03/2023] Open
Abstract
The only true living endothermic vertebrates are birds and mammals, which produce and regulate their internal temperature quite independently from their surroundings. For mammal ancestors, anatomical clues suggest that endothermy originated during the Permian or Triassic. Here we investigate the origin of mammalian thermoregulation by analysing apatite stable oxygen isotope compositions (δ18Op) of some of their Permo-Triassic therapsid relatives. Comparing of the δ18Op values of therapsid bone and tooth apatites to those of co-existing non-therapsid tetrapods, demonstrates different body temperatures and thermoregulatory strategies. It is proposed that cynodonts and dicynodonts independently acquired constant elevated thermometabolism, respectively within the Eucynodontia and Lystrosauridae + Kannemeyeriiformes clades. We conclude that mammalian endothermy originated in the Epicynodontia during the middle-late Permian. Major global climatic and environmental fluctuations were the most likely selective pressures on the success of such elevated thermometabolism. DOI:http://dx.doi.org/10.7554/eLife.28589.001 School textbooks often refer to “cold-blooded” and “warm-blooded” animals, but these terms are misleading. Rather than being cold, animals like reptiles have body temperatures that are mostly determined by their external environment and can actually achieve high body temperatures, for example, by basking in the sun. By contrast, “warm-blooded” mammals produce their own heat and typically maintain a body temperature that is warmer than their environment. As such, so-called warm-blooded animals are more accurately referred to as “endotherms” and cold-blooded animals as “ectotherms”. Endothermic animals share several characteristics, including insulating layers – like fur or feathers – that keep the body warm, and a secondary palate that separates the mouth and nose for continuous breathing, even while eating. Many of these traits are seen in fossils belonging to a group of animals called the therapsids. Also known as the “mammal-like reptiles”, these animals are descended from ectothermic reptiles but are the ancestors of the endothermic mammals. They dominated the land between 270 and 220 million years ago, during periods of time called the Permian and the Triassic. They also survived two major mass extinction events, including the most devastating mass extinction in all of Earth’s history. However, when the ancestors of mammals became truly endothermic remains an open question. Previous studies that have tried to determine this by focusing on the physical characteristics of therapsids have not yet given a consistent date. Rey et al. took a new approach to answer when endothermy first evolved in the mammal-like reptiles, and instead looked at the chemical makeup of minerals in over 100 fossils. Oxygen can exist in different forms called stable isotopes: oxygen-16 and the rarer and heavier oxygen-18. The ratio of these two isotopes in a fossil will depend on, among other things, where the animal lived and, importantly, its body temperature. Therefore, Rey et al. compared oxygen-containing minerals in the bones and teeth of therapsids to those of other animals that lived alongside them to look for signatures that indicated differences in body temperature and how it was regulated. It appears that two different branches of the therapsid’s family tree independently became endothermic. One branch includes the mammals and their direct ancestors, while the second is more distantly related to mammals. Both became endothermic towards the end of the Permian Period, between about 259 and 252 million years ago. Based on these findings, Rey et al. suggest that endothermy allowed these animals to better cope with fluctuating climates, which helped them to be among the few species that survived the mass extinction event at the end of the Permian. Going forward, these new findings can help scientists to understand which physical characteristics were necessary for endothermy to first develop and which helped to optimize it afterwards. Furthermore, they also suggest that endothermic animals are more able to survive fluctuations in climate, which could guide efforts to protect modern-day endangered species that are most at risk from the ongoing effects of climate change. DOI:http://dx.doi.org/10.7554/eLife.28589.002
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Affiliation(s)
- Kévin Rey
- Univ Lyon, Université Lyon 1, Ens de Lyon, CNRS, UMR 5276 LGL-TPE, Villeurbanne, France, France.,Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Romain Amiot
- Univ Lyon, Université Lyon 1, Ens de Lyon, CNRS, UMR 5276 LGL-TPE, Villeurbanne, France, France
| | - François Fourel
- Univ Lyon, Université Lyon 1, Ens de Lyon, CNRS, UMR 5276 LGL-TPE, Villeurbanne, France, France.,Univ Lyon, Université Lyon 1, CNRS, UMR 5023 LEHNA, Villeurbanne, France, France
| | - Fernando Abdala
- Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Nour-Eddine Jalil
- Centre de Recherches en Paléobiodiversité et Paléoenvironnements, UMR 7207 CNRS-MNHN-UPMC, Museum National d'Histoire Naturelle, Paris, France
| | - Jun Liu
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Bruce S Rubidge
- Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Roger Mh Smith
- Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa.,Iziko South African Museum, Cape Town, South Africa
| | - J Sébastien Steyer
- Centre de Recherches en Paléobiodiversité et Paléoenvironnements, UMR 7207 CNRS-MNHN-UPMC, Museum National d'Histoire Naturelle, Paris, France
| | - Pia A Viglietti
- Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Xu Wang
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Christophe Lécuyer
- Univ Lyon, Université Lyon 1, Ens de Lyon, CNRS, UMR 5276 LGL-TPE, Villeurbanne, France, France.,Institut Universitaire de France, Paris, France
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9
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Benton MJ. ECTOTHERMY AND THE SUCCESS OF DINOSAURS. Evolution 2017; 33:983-997. [PMID: 28568443 DOI: 10.1111/j.1558-5646.1979.tb04752.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/1978] [Revised: 10/09/1978] [Indexed: 11/29/2022]
Affiliation(s)
- Michael J Benton
- Department of Geology, The University, Newcastle-upon-Tyne, NE1 7RU, England, U.K
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10
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Tattersall GJ, Leite CAC, Sanders CE, Cadena V, Andrade DV, Abe AS, Milsom WK. Seasonal reproductive endothermy in tegu lizards. SCIENCE ADVANCES 2016; 2:e1500951. [PMID: 26844295 PMCID: PMC4737272 DOI: 10.1126/sciadv.1500951] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/19/2015] [Indexed: 06/05/2023]
Abstract
With some notable exceptions, small ectothermic vertebrates are incapable of endogenously sustaining a body temperature substantially above ambient temperature. This view was challenged by our observations of nighttime body temperatures sustained well above ambient (up to 10°C) during the reproductive season in tegu lizards (~2 kg). This led us to hypothesize that tegus have an enhanced capacity to augment heat production and heat conservation. Increased metabolic rates and decreased thermal conductance are the same mechanisms involved in body temperature regulation in those vertebrates traditionally acknowledged as "true endotherms": the birds and mammals. The appreciation that a modern ectotherm the size of the earliest mammals can sustain an elevated body temperature through metabolic rates approaching that of endotherms enlightens the debate over endothermy origins, providing support for the parental care model of endothermy, but not for the assimilation capacity model of endothermy. It also indicates that, contrary to prevailing notions, ectotherms can engage in facultative endothermy, providing a physiological analog in the evolutionary transition to true endothermy.
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Affiliation(s)
- Glenn J. Tattersall
- Department of Biological Sciences, Brock University, St. Catharines, Ontario L2S 3A1, Canada
- National Institute of Science and Technology in Comparative Physiology (INCT–Fisiologia Comparada), 13505-060 Rio Claro, São Paulo, Brazil
| | - Cleo A. C. Leite
- National Institute of Science and Technology in Comparative Physiology (INCT–Fisiologia Comparada), 13505-060 Rio Claro, São Paulo, Brazil
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Colin E. Sanders
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Viviana Cadena
- Department of Biological Sciences, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Denis V. Andrade
- National Institute of Science and Technology in Comparative Physiology (INCT–Fisiologia Comparada), 13505-060 Rio Claro, São Paulo, Brazil
- Department of Zoology, São Paulo State University (UNESP), 13506-900 Rio Claro, Brazil
| | - Augusto S. Abe
- National Institute of Science and Technology in Comparative Physiology (INCT–Fisiologia Comparada), 13505-060 Rio Claro, São Paulo, Brazil
- Department of Zoology, São Paulo State University (UNESP), 13506-900 Rio Claro, Brazil
| | - William K. Milsom
- National Institute of Science and Technology in Comparative Physiology (INCT–Fisiologia Comparada), 13505-060 Rio Claro, São Paulo, Brazil
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
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11
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Werner YL, Korolker N, Sion G, Göçmen B. Bergmann's and Rensch's rules and the spur-thighed tortoise (Testudo graeca). Biol J Linn Soc Lond 2015. [DOI: 10.1111/bij.12717] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yehudah L. Werner
- The Alexander Silberman Institute of Life Sciences (Dept EEB); The Hebrew University of Jerusalem; 91904 Jerusalem Israel
- Museum für Tierkunde, Senckenberg Dresden; Königsbrücker Landstrasse 159 D-01109 Dresden Germany
| | - Nuphar Korolker
- The Alexander Silberman Institute of Life Sciences (Dept EEB); The Hebrew University of Jerusalem; 91904 Jerusalem Israel
| | - Guy Sion
- The Alexander Silberman Institute of Life Sciences (Dept EEB); The Hebrew University of Jerusalem; 91904 Jerusalem Israel
| | - Bayram Göçmen
- Zoology Section; Department of Biology; Faculty of Science; Ege University; 35100 Bornova-Izmir Turkey
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12
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Activity Patterns and Movements of Free-Ranging Bluetongue Lizards (Tiliqua scincoides intermediaandTiliqua multifasciata) in the Australian Wet-Dry Tropics. J HERPETOL 2014. [DOI: 10.1670/12-256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Grady JM, Enquist BJ, Dettweiler-Robinson E, Wright NA, Smith FA. Dinosaur physiology. Evidence for mesothermy in dinosaurs. Science 2014; 344:1268-72. [PMID: 24926017 DOI: 10.1126/science.1253143] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Were dinosaurs ectotherms or fast-metabolizing endotherms whose activities were unconstrained by temperature? To date, some of the strongest evidence for endothermy comes from the rapid growth rates derived from the analysis of fossil bones. However, these studies are constrained by a lack of comparative data and an appropriate energetic framework. Here we compile data on ontogenetic growth for extant and fossil vertebrates, including all major dinosaur clades. Using a metabolic scaling approach, we find that growth and metabolic rates follow theoretical predictions across clades, although some groups deviate. Moreover, when the effects of size and temperature are considered, dinosaur metabolic rates were intermediate to those of endotherms and ectotherms and closest to those of extant mesotherms. Our results suggest that the modern dichotomy of endothermic versus ectothermic is overly simplistic.
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Affiliation(s)
- John M Grady
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
| | - Brian J Enquist
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. The Santa Fe Institute, USA, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
| | | | - Natalie A Wright
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Felisa A Smith
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
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Sato K. Body temperature stability achieved by the large body mass of sea turtles. J Exp Biol 2014; 217:3607-14. [DOI: 10.1242/jeb.109470] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
To investigate the thermal characteristics of large reptiles living in water, temperature data were continuously recorded from 16 free-ranging loggerhead turtles Caretta caretta during internesting periods using data loggers. Core body temperatures were 0.7-1.7°C higher than ambient water temperatures and were kept relatively constant. Unsteady numerical simulations using a spherical thermodynamic model showed mechanistic explanations for these phenomena and the body temperature responses to fluctuating water temperature can be simply explained by a large body mass with a constant thermal diffusivity and a heat production rate rather than physiological thermoregulation. On the other hand, body temperatures increased 2.6-5.1°C in 107-152 min during their emergences to nest on land. The estimated heat production rates on land were 7.4-10.5 times the calculated values in the sea. The theoretical prediction that temperature difference between body and water temperatures would increase according to the body size was confirmed by empirical data recorded from several species of sea turtles. Comparing previously reported data, internesting intervals of leatherback, green and loggerhead turtles were shorter when the body temperatures were higher. Sea turtles seem to benefit from a passive thermoregulatory strategy, which depends primarily on physical attributes of their large body masses.
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Price-Rees SJ, Lindström T, Brown GP, Shine R. The effects of weather conditions on dispersal behaviour of free-ranging lizards (Tiliqua, Scincidae) in tropical Australia. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12189] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
| | - Tom Lindström
- School of Biological Sciences; University of Sydney; Sydney NSW 2006 Australia
| | - Gregory P. Brown
- School of Biological Sciences; University of Sydney; Sydney NSW 2006 Australia
| | - Richard Shine
- School of Biological Sciences; University of Sydney; Sydney NSW 2006 Australia
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Rowe MF. Response to 'How far did dinosaurs really migrate, and how hot do elephants really get'? J Exp Biol 2013; 216:3762-3. [PMID: 24006350 DOI: 10.1242/jeb.093336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Rowe MF, Bakken GS, Ratliff JJ, Langman VA. Heat storage in Asian elephants during submaximal exercise: behavioral regulation of thermoregulatory constraints on activity in endothermic gigantotherms. J Exp Biol 2013; 216:1774-85. [DOI: 10.1242/jeb.076521] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Gigantic size presents both opportunities and challenges in thermoregulation. Allometric scaling relationships suggest that gigantic animals have difficulty dissipating metabolic heat. Large body size permits the maintenance of fairly constant core body temperatures in ectothermic animals by means of gigantothermy. Conversely, gigantothermy combined with endothermic metabolic rate and activity likely results in heat production rates that exceed heat loss rates. In tropical environments, it has been suggested that a substantial rate of heat storage might result in a potentially lethal rise in core body temperature in both elephants and endothermic dinosaurs. However, the behavioral choice of nocturnal activity might reduce heat storage. We sought to test the hypothesis that there is a functionally significant relationship between heat storage and locomotion in Asian elephants (Elephas maximus), and model the thermoregulatory constraints on activity in elephants and a similarly sized migratory dinosaur, Edmontosaurus. Pre- and post-exercise (N=37 trials) measurements of core body temperature and skin temperature, using thermography were made in two adult female Asian elephants at the Audubon Zoo in New Orleans, LA, USA. Over ambient air temperatures ranging from 8 to 34.5°C, when elephants exercised in full sun, ~56 to 100% of active metabolic heat production was stored in core body tissues. We estimate that during nocturnal activity, in the absence of solar radiation, between 5 and 64% of metabolic heat production would be stored in core tissues. Potentially lethal rates of heat storage in active elephants and Edmontosaurus could be behaviorally regulated by nocturnal activity.
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Affiliation(s)
- M. F. Rowe
- Biology Department, Indiana State University, Terre Haute, IN 47809, USA
| | - G. S. Bakken
- Biology Department, Indiana State University, Terre Haute, IN 47809, USA
| | - J. J. Ratliff
- Audubon Nature Institute, New Orleans, LA 70118, USA
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18
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Thermal variability in body temperature in an ectotherm: Are cloacal temperatures good indicators of tortoise body temperature? J Therm Biol 2013. [DOI: 10.1016/j.jtherbio.2013.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Thermal biology and temperature-based habitat selection in a large aquatic ectotherm, the alligator snapping turtle, Macroclemys temminckii. J Therm Biol 2011. [DOI: 10.1016/j.jtherbio.2011.01.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Couvillon MJ, Fitzpatrick G, Dornhaus A. Ambient Air Temperature Does Not Predict whether Small or Large Workers Forage in Bumble Bees ( Bombus impatiens). PSYCHE; A JOURNAL OF ENTOMOLOGY 2010; 2010:536430. [PMID: 26005222 PMCID: PMC4440703 DOI: 10.1155/2010/536430] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Bumble bees are important pollinators of crops and other plants. However, many aspects of their basic biology remain relatively unexplored. For example, one important and unusual natural history feature in bumble bees is the massive size variation seen between workers of the same nest. This size polymorphism may be an adaptation for division of labor, colony economics, or be nonadaptive. It was also suggested that perhaps this variation allows for niche specialization in workers foraging at different temperatures: larger bees might be better suited to forage at cooler temperatures and smaller bees might be better suited to forage at warmer temperatures. This we tested here using a large, enclosed growth chamber, where we were able to regulate the ambient temperature. We found no significant effect of ambient or nest temperature on the average size of bees flying to and foraging from a suspended feeder. Instead, bees of all sizes successfully flew and foraged between 16°C and 36°C. Thus, large bees foraged even at very hot temperatures, which we thought might cause overheating. Size variation therefore could not be explained in terms of niche specialization for foragers at different temperatures.
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Affiliation(s)
- Margaret J. Couvillon
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
- Laboratory of Apiculture and Social Insects, Department of Biological and Environmental Science, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Ginny Fitzpatrick
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Anna Dornhaus
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
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24
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McNab BK. Resources and energetics determined dinosaur maximal size. Proc Natl Acad Sci U S A 2009; 106:12184-8. [PMID: 19581600 PMCID: PMC2715483 DOI: 10.1073/pnas.0904000106] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Indexed: 11/18/2022] Open
Abstract
Some dinosaurs reached masses that were approximately 8 times those of the largest, ecologically equivalent terrestrial mammals. The factors most responsible for setting the maximal body size of vertebrates are resource quality and quantity, as modified by the mobility of the consumer, and the vertebrate's rate of energy expenditure. If the food intake of the largest herbivorous mammals defines the maximal rate at which plant resources can be consumed in terrestrial environments and if that limit applied to dinosaurs, then the large size of sauropods occurred because they expended energy in the field at rates extrapolated from those of varanid lizards, which are approximately 22% of the rates in mammals and 3.6 times the rates of other lizards of equal size. Of 2 species having the same energy income, the species that uses the most energy for mass-independent maintenance of necessity has a smaller size. The larger mass found in some marine mammals reflects a greater resource abundance in marine environments. The presumptively low energy expenditures of dinosaurs potentially permitted Mesozoic communities to support dinosaur biomasses that were up to 5 times those found in mammalian herbivores in Africa today. The maximal size of predatory theropods was approximately 8 tons, which if it reflected the maximal capacity to consume vertebrates in terrestrial environments, corresponds in predatory mammals to a maximal mass less than a ton, which is what is observed. Some coelurosaurs may have evolved endothermy in association with the evolution of feathered insulation and a small mass.
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Affiliation(s)
- Brian K McNab
- Department of Zoology, University of Florida, Gainesville, FL 32611, USA.
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25
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RANDOLPH SARAHE. The relative timing of the origin of flight and endothermy: evidence from the comparative biology of birds and mammals. Zool J Linn Soc 2008. [DOI: 10.1111/j.1096-3642.1994.tb00327.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bradshaw CJA, McMahon CR, Hays GC. Behavioral Inference of Diving Metabolic Rate in Free‐Ranging Leatherback Turtles. Physiol Biochem Zool 2007; 80:209-19. [PMID: 17252517 DOI: 10.1086/511142] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2006] [Indexed: 11/03/2022]
Abstract
Good estimates of metabolic rate in free-ranging animals are essential for understanding behavior, distribution, and abundance. For the critically endangered leatherback turtle (Dermochelys coriacea), one of the world's largest reptiles, there has been a long-standing debate over whether this species demonstrates any metabolic endothermy. In short, do leatherbacks have a purely ectothermic reptilian metabolic rate or one that is elevated as a result of regional endothermy? Recent measurements have provided the first estimates of field metabolic rate (FMR) in leatherback turtles using doubly labeled water; however, the technique is prohibitively expensive and logistically difficult and produces estimates that are highly variable across individuals in this species. We therefore examined dive duration and depth data collected for nine free-swimming leatherback turtles over long periods (up to 431 d) to infer aerobic dive limits (ADLs) based on the asymptotic increase in maximum dive duration with depth. From this index of ADL and the known mass-specific oxygen storage capacity (To(2)) of leatherbacks, we inferred diving metabolic rate (DMR) as To2/ADL. We predicted that if leatherbacks conform to the purely ectothermic reptilian model of oxygen consumption, these inferred estimates of DMR should fall between predicted and measured values of reptilian resting and field metabolic rates, as well as being substantially lower than the FMR predicted for an endotherm of equivalent mass. Indeed, our behaviorally derived DMR estimates (mean=0.73+/-0.11 mL O(2) min(-1) kg(-1)) were 3.00+/-0.54 times the resting metabolic rate measured in unrestrained leatherbacks and 0.50+/-0.08 times the average FMR for a reptile of equivalent mass. These DMRs were also nearly one order of magnitude lower than the FMR predicted for an endotherm of equivalent mass. Thus, our findings lend support to the notion that diving leatherback turtles are indeed ectothermic and do not demonstrate elevated metabolic rates that might be expected due to regional endothermy. Their capacity to have a warm body core even in cold water therefore seems to derive from their large size, heat exchangers, thermal inertia, and insulating fat layers and not from an elevated metabolic rate.
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Affiliation(s)
- Corey J A Bradshaw
- School for Environmental Research, Institute of Advanced Studies, Charles Darwin University, Darwin, Northern Territory 0909, Australia.
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Ruben JA, Jones TD, Geist NR. Respiratory and reproductive paleophysiology of dinosaurs and early birds. Physiol Biochem Zool 2003; 76:141-64. [PMID: 12794669 DOI: 10.1086/375425] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2003] [Indexed: 11/03/2022]
Abstract
In terms of their diversity and longevity, dinosaurs and birds were/are surely among the most successful of terrestrial vertebrates. Unfortunately, interpreting many aspects of the biology of dinosaurs and the earliest of the birds presents formidable challenges because they are known only from fossils. Nevertheless, a variety of attributes of these taxa can be inferred by identification of shared anatomical structures whose presence is causally linked to specialized functions in living reptiles, birds, and mammals. Studies such as these demonstrate that although dinosaurs and early birds were likely to have been homeothermic, the absence of nasal respiratory turbinates in these animals indicates that they were likely to have maintained reptile-like (ectothermic) metabolic rates during periods of rest or routine activity. Nevertheless, given the metabolic capacities of some extant reptiles during periods of elevated activity, early birds were probably capable of powered flight. Similarly, had, for example, theropod dinosaurs possessed aerobic metabolic capacities and habits equivalent to those of some large, modern tropical latitude lizards (e.g., Varanus), they may well have maintained significant home ranges and actively pursued and killed large prey. Additionally, this scenario of active, although ectothermic, theropod dinosaurs seems reinforced by the likely utilization of crocodilian-like, diaphragm breathing in this group. Finally, persistent in vivo burial of their nests and apparent lack of egg turning suggests that clutch incubation by dinosaurs was more reptile- than birdlike. Contrary to previous suggestions, there is little if any reliable evidence that some dinosaur young may have been helpless and nestbound (altricial) at hatching.
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Affiliation(s)
- John A Ruben
- Zoology Department, Oregon State University, Corvallis, OR 97331-2914, USA.
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30
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Abstract
Data concerning the energy expenditure of nine species in the family Felidae and one species in the family Hyaenidae are presented, all of which were obtained under standard conditions. An examination of basal rates of metabolism in these felids and in two species reported in the literature indicates that basal rate is primarily correlated with body mass; of these species, nine have a high basal metabolic rate by general mammalian standards, the two exceptions being the margay and jaguarundi. The low basal metabolic rate of the margay may be related to its arboreal habit in association with small muscle mass, but the reason for the low rate in the jaguarundi is unknown. The omnivorous striped hyaena and termitivorous aardwolf have typical mammalian basal rates. Felids that weigh less than 7 kg have slightly low minimal thermal conductances relative to mammals generally; larger species have high conductances. Felids have slightly high body temperatures.
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31
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O'Connor MP. Extracting operative temperatures from temperatures of physical models with thermal inertia. J Therm Biol 2000; 25:329-343. [PMID: 10838172 DOI: 10.1016/s0306-4565(99)00102-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Temperatures of operative temperature models, particularly those of thick-walled models of larger ectotherms, lag behind and are more restricted in range than the operative temperatures they estimate.Algorithms are provided to extract estimates of instantaneous operative temperatures from model temperatures.A simple deconvolution method can be used when wind speeds are constant.An iterative estimation method must be used when wind speed varies during the monitoring period.The iterative method is sensitive to measurement error, and so uses a smoothing filter to limit instabilities. The smoothing also limits the short-term fluctuations in the estimated operative temperature.Iterative estimates of operative temperature suggested time lags of up to 90 min between predicted operative temperatures and model temperatures for desert tortoises (mass=3 kg). Differences this large could affect estimates of time available for foraging.
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Affiliation(s)
- MP O'Connor
- Department of Bioscience and Biotechnology, Drexel University, 19104, Philadelphia, PA, USA
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Grigg GC, Seebacherd F, Beard LA, Morris D. Thermal relations of large crocodiles, Crocodylus porosus, free—ranging in a naturalistic situation. Proc Biol Sci 1998. [DOI: 10.1098/rspb.1998.0504] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Gordon C. Grigg
- Department of Zoology, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Frank Seebacherd
- Department of Zoology, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Lyn A. Beard
- Department of Zoology, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Don Morris
- Edward River Crocodile Farm Proprietary Ltd, Redbank, Queensland 4871, Australia
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34
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Thompson GG, Withers PC. Standard and maximal metabolic rates of goannas (Squamata:Varanidae). PHYSIOLOGICAL ZOOLOGY 1997; 70:307-23. [PMID: 9231405 DOI: 10.1086/639605] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Standard metabolic rate and maximal metabolic rate during forced exercise are examined for nine species of goanna (genus Varanus), with body mass varying from 10 to 3,750 g. At 35 degrees C, the common pooled mass exponent for standard metabolic rate is 0.97 and at 25 degrees C it is 0.89, with considerable variation between species (0.43-1.20). Standard metabolic rate at 35 degrees C scales interspecifically with body mass0.92 and at 25 degrees C with body mass0.87. The Q10 for standard metabolic rate is approximately 2.5 between 25 degrees and 35 degrees C. At 35 degrees C, maximal metabolic rate scales intraspecifically with body mass0.79 and scales interspecifically with body mass0.72. Factorial metabolic scope ranges from nine for the larger species to 35 for the smaller species; it scales with body mass-0.199 at 35 degrees C. The maximal metabolic rate of 6.36 mL O2 g-1 h-1 for Varanus caudolineatus is the highest recorded for any squamate. Variations from the interspecific regression line appear to have some ecological significance. Varanus tristis (a widely foraging arboreal goanna) and Varanus eremius (a widely foraging terrestrial goanna) have a higher standard metabolic rate than Varanus acanthurus (a sedentary terrestrial goanna). The three arboreal goannas (Varanus caudolineatus, Varanus gilleni, and Varanus tristis) have a higher maximal metabolic rate than the terrestrial species (Varanus brevicauda, V. eremius, V. acanthurus, Varanus gouldii, Varanus rosenbergi, and Varanus panoptes).
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Affiliation(s)
- G G Thompson
- Centre for Ecosystem Management, Edith Cowan University, Joondalup, Western Australia, Australia.
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A radio-telemetric study of the thermoregulation of free living water monitor lizards, Varanus S. salvator. J Comp Physiol B 1995. [DOI: 10.1007/bf00301476] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Thermoregulation, water turnover and energetics of free-living komodo dragons, Varanus komodoensis. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0300-9629(91)90241-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Slip DJ, Shine R. Thermophilic response to feeding of the diamond python, Morelia s. spilota (Serpentes: Boidae). ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0300-9629(88)90847-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Smith KK. Morphology and function of the tongue and hyoid apparatus in Varanus (Varanidae, Lacertilia). J Morphol 1986; 187:261-87. [PMID: 3701871 DOI: 10.1002/jmor.1051870302] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The morphology and function of the tongue and hyoid apparatus in Varanus were examined by anatomical and experimental techniques. Morphological features unique to Varanus include a highly protrusible tongue that has lost a roughened dorsal surface, an exceptionally strong and mobile hyobranchial apparatus, a well-defined joint between the ceratohyal and anterior process, and a series of distinct muscles inserting at the anterior hyobranchial region. Varanus is also unusual among lizards in a number of feeding behaviors; it ingests prey entirely by inertial feeding, as the tongue does not participate in food transport. Further specializations include an increased reliance on hyobranchial movements in drinking and pharyngeal packing and compression. The long, narrow tongue is most likely related to the mechanics of tongue protrusion; the increased amount, strength, and complexity of hyobranchial movement is related to the fact that the hyobranchium in Varanus replaces the tongue in many functions. Previous hypotheses for the origin of these adaptations are discussed, and the difficulties of attributing these specializations to any specific scenario of adaptation or constraint are emphasized.
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The physiology of exercise at and above maximal aerobic capacity in a theraphosid (tarantula) spider,Brachypelma smithi (F.O. Pickard-Cambridge). J Comp Physiol B 1985. [DOI: 10.1007/bf00694442] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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45
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Carothers JH. Size-related activity patterns in an herbivorous lizard. Oecologia 1983; 57:103-106. [DOI: 10.1007/bf00379567] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/1982] [Indexed: 11/28/2022]
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Rhodin AGJ, Ogden JA, Conlogue GJ. Chondro-osseous morphology of Dermochelys coriacea, a marine reptile with mammalian skeletal features. Nature 1981. [DOI: 10.1038/290244a0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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50
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Wood SC, Glass ML, Johansen K. Effects of temperature on respiration and acid-base balance in a monitor lizard. ACTA ACUST UNITED AC 1977. [DOI: 10.1007/bf00689037] [Citation(s) in RCA: 44] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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