DOCSLIB.ORG

Core and Body Surface Temperatures of Nesting Leatherback Turtles (Dermochelys Coriacea)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Core and Body Surface Temperatures of Nesting Leatherback Turtles (Dermochelys Coriacea) Journal of Thermal Biology 51 (2015) 15–22 Contents lists available at ScienceDirect Journal of Thermal Biology journal homepage: www.elsevier.com/locate/jtherbio Core and body surface temperatures of nesting leatherback turtles (Dermochelys coriacea) Thomas J. Burns n, Dominic J. McCafferty, Malcolm W. Kennedy n Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, Scotland, UK article info abstract Article history: Leatherback turtles (Dermochelys coriacea) are the largest species of marine turtle and the fourth most Received 27 November 2014 massive extant reptile. In temperate waters they maintain body temperatures higher than surrounding Received in revised form seawater through a combination of insulation, physiological, and behavioural adaptations. Nesting in- 27 February 2015 volves physical activity in addition to contact with warm sand and air, potentially presenting thermal Accepted 1 March 2015 challenges in the absence of the cooling effect of water, and data are lacking with which to understand Available online 3 March 2015 their nesting thermal biology. Using non-contact methods (thermal imaging and infrared thermometry) Keywords: to avoid any stress-related effects, we investigated core and surface temperature during nesting. The Thermal biology mean7SE core temperature was 31.470.05 °C (newly emerged eggs) and was not correlated with en- Thermography vironmental conditions on the nesting beach. Core temperature of leatherbacks was greater than that of Non-invasive techniques hawksbill turtles (Eretmochelys imbricata) nesting at a nearby colony, 30.070.13 °C. Body surface tem- Core temperature Dermochelys coriacea peratures of leatherbacks showed regional variation, the lateral and dorsal regions of the head were Eretmochelys imbricata warmest while the carapace was the coolest surface. Surface temperature increased during the early nesting phases, then levelled off or decreased during later phases with the rates of change varying be- tween body regions. Body region, behavioural phase of nesting and air temperature were found to be the best predictors of surface temperature. Regional variation in surface temperature were likely due to alterations in blood supply, and temporal changes in local muscular activity of flippers during the dif- ferent phases of nesting. Heat exchange from the upper surface of the turtle was dominated by radiative heat loss from all body regions and small convective heat gains to the carapace and front flippers. & 2015 Elsevier Ltd. All rights reserved. 1. Introduction Casey et al., 2014). Thermoregulation is aided by counter-current heat exchangers within the front and rear flippers (Greer et al., Leatherback turtles (Dermochelys coriacea) are the largest spe- 1973), a vascular plexus lining the trachea to reduce respiratory cies of marine turtle, with adult females having a mean mass of heat loss, analogous to that of nasal turbinates found in birds and around 400 kg (Georges and Fossette, 2006). As adults they inhabit mammals (Davenport et al., 2009a), extensive adipose tissues in a broad range of water temperatures, migrating between high la- the head and neck, and major blood vessels buried deep within titude, prey-rich temperate waters and the tropics or subtropics, the insulated neck (Davenport et al., 2009b). where beaches provide the conditions for laying and development In addition to these physiological adaptations for controlling of eggs. Leatherbacks exhibit a range of physiological and beha- heat loss, behaviour plays a key role in temperature control. vioural adaptations to cope with different environmental tem- Swimming (and the consequent metabolic heating) maintains a peratures, allowing them to remain active in temperate waters and high body to water temperature differential (Bostrom and Jones, prevent overheating in the tropics. Their thermoregulatory strat- 2007) and turtles change flipper stroke rate in response to dif- egy likely involves aspects of both gigantothermy due to their ferent water temperatures (Bostrom et al., 2010). Furthermore, large body mass, extensive fatty insulating tissue layers and leatherbacks may dive to cooler waters to lose heat in tropical adaptable blood circulation system (Paladino et al., 1990), and waters (Southwood et al., 2005; Bostrom and Jones, 2007) and, endothermy due to internal heat production (Bostrom et al., 2010; conversely, in temperate seas may bring prey items to the surface to warm them before ingestion (James and Mrosovsky, 2004). n Nesting is the only time when female leatherbacks are known to Corresponding authors. E-mail addresses: [email protected] (T.J. Burns), return to land, the process may last over two hours, and requires, [email protected] (M.W. Kennedy). with the exception of egg laying, extensive use of the flippers http://dx.doi.org/10.1016/j.jtherbio.2015.03.001 0306-4565/& 2015 Elsevier Ltd. All rights reserved. 16 T.J. Burns et al. / Journal of Thermal Biology 51 (2015) 15–22 Table 1 Published values for leatherback body temperature shown alongside values derived from this study. o Mean TB7SE (range) C Method of measurement Location (turtle activity) n Source 31.4 70.05 (30.6–32.5) Egg surface temperature (corrected) Trinidad (nesting-laying) 65 This study 29.170.23 (27.3–30.6) Sub-carapace Costa Rica (inter-nesting) 3 Southwood et al. (2005) 30.270.35 (27.1–33.2) Gastrointestinal Costa Rica (inter-nesting) 4 Southwood et al. (2005) 28.370.07 (28.1–28.7) Gastrointestinal USVI (inter-nesting) 8 Casey et al. (2010) 31.1n (30.5–33.5) Egg temperature Mexico (nesting) 10 Mrosovsky (1980) 30.6 (29.8–31.4) Egg temperature French Guiana /Suriname (nesting) 24 Mrosovsky, Pritchard (1971) 3370.45 (32–34) Not specified Costa Rica (nesting-restrained post laying) 5 Lutcavage et al. (1992) 31.6 70.3 Inserted 25–30 cm into body through drilled hole Costa Rica (nesting-restrained post sand scattering) 10 Paladino et al. (1996) 30.870.2 Inserted 25–30 cm into body through drilled hole Costa Rica (nesting-laying) 3 Paladino et al. (1996) 31.4 70.4 Inserted 25–30 cm into body through drilled hole Costa Rica (nesting-‘exercising’)10Paladino et al. (1996) 31.5 Gastrointestinal (juvenile- 37 kg) Laboratory (in water tank) 1 Bostrom et al. (2010) 31.8 Gastrointestinal (juvenile- 16 kg) Laboratory (in water tank) 1 Bostrom et al. (2010) 26.470.23 (25.4–27.3) Gastrointestinal Northwest Atlantic (foraging) 7 Casey et al. (2014) 24.3370.94 (21.6–25.8) Cloacal Nova Scotia (restrained) 4 James and Mrosovsky (2004) n Represents a median value, values from this study are shown in bold. (Eckert et al., 2012). Flipper movement has been suggested as the the nest hole; 4-laying; 5-refilling the nest hole; 6-sand scattering primary source of heat production at sea (Bostrom and Jones, (also termed ‘camouflaging’ and ‘disguise’ elsewhere in the lit- 2007; Bostrom et al., 2010) and it is likely that flipper activity erature); 7-return to the sea (for a full description of nesting during nesting will result in substantial heat production. Biophy- phases see Table S1). sical modelling suggests that core temperature of leatherbacks increases throughout the nesting process and rises in core tem- 2.2. Body core temperature perature during nesting are predicted as a result of future rising temperatures in their breeding range (Dudley and Porter, 2014). The surface temperature of freshly laid eggs was used as a non- However, measurements on land of core temperature in this contact proxy of core body temperature. Measurements were ta- species are, surprisingly, relatively scarce (Table 1). þ The aims of this study were, first, to estimate the core tem- ken using a Fluke 62 Max portable infrared thermometer ¼ – m ¼ ° perature of nesting leatherbacks, second, to examine spatial and (spectral range 8 14 m, accuracy 1 C or 1%, thermal ¼ ° temporal variation in surface temperature through all phases of sensitivity 0.1 C) set to an emissivity of 0.98, which is within the nesting behaviour, and, third, to estimate the relationships be- range of previously used values for emissivity of living tissues tween both core and surface body temperatures and the en- (McCafferty et al., 2013; Rowe et al., 2013; Mortola, 2013). Infrared vironmental conditions on the nesting beaches. An important and thermometers were calibrated against a thermocouple, which had novel aspect of this study was that all measurements were made itself been calibrated against a mercury thermometer of 0.1 °C with minimal or no disturbance using non-contact thermometry sensitivity. The recorder lay in the sand with one arm extended and thermal imaging. For comparison we also estimated the core into the nest hole (some sand was removed from one side of the temperatures of ectothermic nesting hawksbill turtles (Eretmo- nest hole to allow better access) and observed the eggs as they chelys imbricata). were laid. Measurements were taken only on eggs that were freshly laid (within one or two seconds of emergence) and had no sand attached to the side which was being measured. As mea- 2. Materials and methods surements of surface temperature were taken so soon after the eggs emerged from the female the effects of variation in cooling 2.1. Study area and discrimination of nesting phases rates between eggs will be negligible. Measurements were also taken for nesting hawksbill turtles (to provide a smaller ec- Fieldwork on leatherback turtles was carried out at Fishing tothermic comparator) at Hermitage Bay, Tobago (approximately Pond Beach (approximately 10.58° N, 61.02° W) on the East coast 11.31° N, 60.57° W) using the same methods. of Trinidad, West Indies. Fishing Pond is one of three protected To correct for potential post-laying cooling and/or inaccuracy beaches on the island which receive high densities of nesting fe- due to imprecise emissivity setting, a correction factor for egg male leatherbacks during the nesting season which runs from surface temperature was estimated and applied to all measure- March to the end of August, peak nesting occurring during April ments of both study species.
Load more

Recommended publications
  • Sizing Ocean Giants: Patterns of Intraspecific Size Variation in Marine Megafauna
    Sizing ocean giants: patterns of intraspecific size variation in marine megafauna Craig R. McClain1,2 , Meghan A. Balk3, Mark C. Benfield4, Trevor A. Branch5, Catherine Chen2, James Cosgrove6, Alistair D.M. Dove7, Lindsay C. Gaskins2, Rebecca R. Helm8, Frederick G. Hochberg9, Frank B. Lee2, Andrea Marshall10, Steven E. McMurray11, Caroline Schanche2, Shane N. Stone2 and Andrew D. Thaler12 1 National Evolutionary Synthesis Center, Durham, NC, USA 2 Department of Biology, Duke University, Durham, NC, USA 3 Department of Biology, University of New Mexico, Albuquerque, NM, USA 4 Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA 5 School of Aquatic & Fishery Sciences, University of Washington, Seattle, WA, USA 6 Natural History Section, Royal British Columbia Museum, Victoria, BC, Canada 7 Georgia Aquarium, Atlanta, GA, USA 8 Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA 9 Department of Invertebrate Zoology, Santa Barbara Museum of Natural History, Santa Barbara, CA, USA 10 Marine Megafauna Foundation, Truckee, CA, USA 11 Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA 12 Blackbeard Biologic: Science and Environmental Advisors, Vallejo, CA, USA ABSTRACT What are the greatest sizes that the largest marine megafauna obtain? This is a simple question with a diYcult and complex answer. Many of the largest-sized species occur in the world’s oceans. For many of these, rarity, remoteness, and quite simply the logistics of measuring these giants has made obtaining accurate size measurements diYcult. Inaccurate reports of maximum sizes run rampant through the scientific Submitted 3 October 2014 literature and popular media.
    [Show full text]
  • Phylogenetic Analysis of the Allometry of Metabolic Rate and Mitochondrial Basal Proton Leak
    Author’s Accepted Manuscript Phylogenetic analysis of the allometry of metabolic rate and mitochondrial basal proton leak Elias T. Polymeropoulos, R. Oelkrug, C.R. White, M. Jastroch www.elsevier.com/locate/jtherbio PII: S0306-4565(16)30294-7 DOI: http://dx.doi.org/10.1016/j.jtherbio.2017.01.013 Reference: TB1878 To appear in: Journal of Thermal Biology Received date: 28 September 2016 Revised date: 24 January 2017 Accepted date: 25 January 2017 Cite this article as: Elias T. Polymeropoulos, R. Oelkrug, C.R. White and M. Jastroch, Phylogenetic analysis of the allometry of metabolic rate and mitochondrial basal proton leak, Journal of Thermal Biology, http://dx.doi.org/10.1016/j.jtherbio.2017.01.013 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Phylogenetic analysis of the allometry of metabolic rate and mitochondrial basal proton leak 1 2 3 4,5 Polymeropoulos Elias T. , Oelkrug R. , White C.R. , Jastroch M. 1Menzies Institute for Medical Research, University of Tasmania, 7001 Hobart, Australia, 2Center of Brain, Behaviour and Metabolism, University of Lübeck, 23562 Lübeck, Germany, 3Centre for Geometric Biology, School of Biological Sciences, Monash University, 3800 Melbourne, Australia 4Institute for Diabetes and Obesity, Helmholtz Zentrum, 85764 Munich, Germany, 5 Department of Animal Physiology, Faculty of Biology, Philipps University of Marburg, D-35032 Marburg, Germany Abstract The mitochondrial basal proton leak (MBPL) significantly contributes to high body temperatures (Tb) and basal metabolic rates (BMR) in endotherms.
    [Show full text]
  • Dinosaur Metabolism and the Allometry of Maximum Growth Rate
    RESEARCH ARTICLE Dinosaur Metabolism and the Allometry of Maximum Growth Rate Nathan P. Myhrvold* Intellectual Ventures, Bellevue, Washington, United States of America * [email protected] Abstract a11111 The allometry of maximum somatic growth rate has been used in prior studies to classify the metabolic state of both extant vertebrates and dinosaurs. The most recent such studies are reviewed, and their data is reanalyzed. The results of allometric regressions on growth rate are shown to depend on the choice of independent variable; the typical choice used in prior studies introduces a geometric shear transformation that exaggerates the statistical OPEN ACCESS power of the regressions. The maximum growth rates of extant groups are found to have a Citation: Myhrvold NP (2016) Dinosaur great deal of overlap, including between groups with endothermic and ectothermic metabo- Metabolism and the Allometry of Maximum lism. Dinosaur growth rates show similar overlap, matching the rates found for mammals, Growth Rate. PLoS ONE 11(11): e0163205. reptiles and fish. The allometric scaling of growth rate with mass is found to have curvature doi:10.1371/journal.pone.0163205 (on a log-log scale) for many groups, contradicting the prevailing view that growth rate Editor: Anthony Fiorillo, Perot Museum of Nature allometry follows a simple power law. Reanalysis shows that no correlation between growth and Science, UNITED STATES rate and basal metabolic rate (BMR) has been demonstrated. These findings drive a con- Received: January 7, 2015 clusion that growth rate allometry studies to date cannot be used to determine dinosaur Accepted: September 6, 2016 metabolism as has been previously argued.
    [Show full text]
  • Thermoregulation Strategies of Deep Diving Ectothermic Sharks
    THERMOREGULATION STRATEGIES OF DEEP DIVING ECTOTHERMIC SHARKS A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAIʻI AT MĀNOA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCOTOR OF PHILOSOPHY IN ZOOLOGY (MARINE BIOLOGY) AUGUST 2020 By. Mark A. Royer Dissertation Committee: Kim Holland, Chairperson Brian Bowen Carl Meyer Andre Seale Masato Yoshizawa Keywords: Ectothermic, Thermoregulation, Biologging, Hexanchus griseus, Syphrna lewini, Shark ACKNOWLEDGEMENTS Thank you to my advisor Dr. Kim Holland and to Dr. Carl Meyer for providing me the privilege to pursue a doctoral degree in your lab, which provided more experiences and opportunities than I could have ever imagined. The research environment you provided allowed me to pursue new frontiers in the field and take on challenging questions. Thank you to my committee members Dr. Brian Bowen, Dr. Andre Seale, and Dr. Masato Yoshizawa, for providing your ideas, thoughts, suggestions, support and encouragement through the development of my dissertation. I would like to give my sincere thanks to all of my committee members and to the Department of Biology for taking their time to provide their support and accommodation as I finished my degree during a rather unprecedented and uncertain time. I am very grateful to everyone at the HIMB Shark Lab including Dr. Melanie Hutchinson, Dr. James Anderson, Jeff Muir, and Dr. Daniel Coffey. I learned so much from all of you and we have shared several lifetimes worth of experiences. Thank you to Dr. James Anderson for exciting side projects we have attempted and will continue to pursue in the future. Thank you to Dr.
    [Show full text]
  • Teacher Resource For: Evidence for Mesothermy in Dinosaurs
    Teacher Resource for: Evidence for mesothermy in dinosaurs Table of Contents: I. Student Learning Goals II. Connect to Learning Standards III. Summary of the Article for the Teacher IV. Discussion Questions V. Related Multimedia Resources from HHMI|BioInteractive NOTE: To explore mass extinctions, including the end of the dinosaurs, we recommend HHMI's free eBook Mass Extinctions: Lessons from the Past. Student Learning Goals Connections to the nature of science from the article Were dinosaurs slow-metabolizing ectotherms like reptiles or fast-metabolizing endotherms like mammals and birds whose activities were unconstrained by temperature? How can the resting metabolic rate of extinct species be determined using fossils? The importance of this scientific research This research furthers the understanding of how dinosaurs regulated their body temperature in comparison to known ectotherms and endotherms. It determines the resting metabolic rate of dinosaurs using maximum growth rate as measured by bone growth rings. The actual science involved Thermodynamics Paleontology Connect to Learning Standards: The Next Generation Science Standards Science and Engineering Practice 2: Developing and using models Science and Engineering Practice 6: Constructing explanations (for science) and designing solutions (for engineering) The AP Biology Standards Essential knowledge 1.A.4: Biological evolution is supported by scientific evidence from many disciplines, including mathematics. Essential knowledge 2.A.1: All living systems require constant input of free energy. Essential knowledge 2.C.2: Organisms respond to changes in their external environments. Essential knowledge 2.D.2: Homeostatic mechanisms reflect both common ancestry and divergence due to adaptation in different environments. Common Core English Language Arts 11.12.8: Evaluate the hypotheses, data, analyses, and conclusions in a science or technical test, verifying the data when possible and corroborating or challenging conclusions with other sources of information.
    [Show full text]
  • Migration and Habitat Utilization in Lamnid Sharks
    MIGRATION AND HABITAT UTILIZATION IN LAMNID SHARKS A DISSERTATION SUBMITTED TO THE DEPARTMENT OF BIOLOGICAL SCIENCES AND THE COMMITTEE ON GRADUATE STUDIES OF STANFORD UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Kevin Chi-Ming Weng May 2007 © Copyright by Kevin Chi-Ming Weng 2007 All Rights Reserved ii Abstract Understanding the movements, habitat utilization, and life history of high trophic level animals is essential to understanding how ecosystems function. Furthermore, large pelagic vertebrates, including sharks, are declining globally, yet the movements and habitats of most species are unknown. A variety of satellite telemetry techniques are used to elucidate the movements and habitat utilization of two species of lamnid shark. Salmon sharks used a subarctic to subtropical niche, and undertook long distance seasonal migrations between subarctic and subtropical regions of the eastern North Pacific, exhibiting the greatest focal area behavior in the rich neritic waters off Alaska and California, and showing more transitory behaviors in pelagic waters where productivity is lower. The timing of salmon shark aggregations in both Alaska and California waters appears to correspond with life history events of an important group of prey species, Pacific salmon. The enhanced expression of excitation-contraction coupling proteins in salmon shark hearts likely underlies its ability to maintain heart function at cold temperatures and their niche expansion into subarctic seas. Adult white sharks undertake long distance seasonal migrations from the coast of California to an offshore focal area 2500 km west of the Baja Peninsula, as well as Hawaii. A full migration cycle from the coast to the offshore focal area and back was documented.
    [Show full text]
  • Thermoregulation in the Leatherback Sea Turtle (Dermochelys Coriacea)
    Thermoregulation in the leatherback sea turtle (Dermochelys coriacea ) by Brian Lee Bostrom B.Sc., The University of British Columbia, 2005 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Zoology) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) August 2009 © Brian Lee Bostrom, 2009 ABSTRACT Adult leatherback turtles ( Dermochelys coriacea ) exhibit thermal gradients between their bodies and the environment of ≥ 8 °C in sub-polar waters and ≤ 4 °C in the tropics. There has been no direct evidence for thermoregulation in leatherbacks although modelling and morphological studies have given an indication of how thermoregulation may be achieved. Using a cylindrical model of a leatherback I investigated the extent to which heat production by muscle activity during variation of swim speed could be used in a leatherback’s thermal strategy. Drag force of a full scale cast of a leatherback was measured in a low velocity wind tunnel to obtain an estimate of the metabolic cost needed to offset drag. It is apparent, from this modelling, that heat flux from the body and flippers, activity and body and water temperatures are important variables to measure in order to fully classify the thermoregulatory response of live leatherbacks. Using captive juvenile leatherbacks of 16 and 37 kg I show for the first time that leatherbacks are indeed capable of thermoregulation. In cold water (< 25 °C), flipper stroke frequency increased, heat loss through the plastron, carapace and flippers was minimized, and a positive thermal gradient of up to 2.3 °C was maintained between body and environment.
    [Show full text]
  • Implications for Foraging Efficiency and Thermoregulation
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Frontiers - Publisher Connector ORIGINAL RESEARCH published: 15 September 2015 doi: 10.3389/fmars.2015.00064 Swimming strategy and body plan of the world’s largest fish: implications for foraging efficiency and thermoregulation Mark G. Meekan 1*, Lee A. Fuiman 2, Randall Davis 3, Yuval Berger 1 and Michele Thums 1 1 The Australian Institute of Marine Science, Crawley, WA, Australia, 2 Marine Science Institute, The University of Texas at Austin, Port Aransas, TX, USA, 3 Department of Marine Biology, Texas A&M University, Galveston, TX, USA The largest animals in the oceans eat prey that are orders of magnitude smaller than themselves, implying strong selection for cost-effective foraging to meet their energy demands. Whale sharks (Rhincodon typus) may be especially challenged by warm seas Edited by: Graeme Clive Hays, that elevate their metabolism and contain sparse prey resources. Using a combination Deakin University, Australia of biologging and satellite tagging, we show that whale sharks use four strategies Reviewed by: to save energy and improve foraging efficiency: (1) fixed, low power swimming, (2) Gail Schofield, Deakin University, Australia constant low speed swimming, (3) gliding, and (4) asymmetrical diving. These strategies Nuno Queiroz, increase foraging efficiency by 22–32% relative to swimming horizontally and resolve University of Porto, Portugal the energy-budget paradox of whale sharks. However, sharks in the open ocean must Michael Brian Bennett, ◦ The University of Queensland, access food resources that reside in relatively cold waters (up to 20 C cooler than the Australia surface) at depths of 250–500 m during the daytime, where long, slow gliding descents, *Correspondence: continuous ram ventilation of the gills and filter-feeding could rapidly cool the circulating Mark G.
    [Show full text]
  • Isotopic Ordering in Eggshells Reflects Body Temperatures And
    ARTICLE Received 19 Oct 2014 | Accepted 7 Aug 2014 | Published 13 Oct 2015 DOI: 10.1038/ncomms9296 Isotopic ordering in eggshells reflects body temperatures and suggests differing thermophysiology in two Cretaceous dinosaurs Robert A. Eagle1,2,3,4, Marcus Enriquez1, Gerald Grellet-Tinner5,6, Alberto Pe´rez-Huerta7, David Hu2, Thomas Tu¨tken8, Shaena Montanari9, Sean J. Loyd1,10, Pedro Ramirez11, Aradhna K. Tripati1,3,4,12, Matthew J. Kohn13, Thure E. Cerling14, Luis M. Chiappe15 & John M. Eiler2 Our understanding of the evolutionary transitions leading to the modern endothermic state of birds and mammals is incomplete, partly because tools available to study the thermo- physiology of extinct vertebrates are limited. Here we show that clumped isotope analysis of eggshells can be used to determine body temperatures of females during periods of ovulation. Late Cretaceous titanosaurid eggshells yield temperatures similar to large modern endo- therms. In contrast, oviraptorid eggshells yield temperatures lower than most modern endotherms but B6 °C higher than co-occurring abiogenic carbonates, implying that this taxon did not have thermoregulation comparable to modern birds, but was able to elevate its body temperature above environmental temperatures. Therefore, we observe no strong evidence for end-member ectothermy or endothermy in the species examined. Body tem- peratures for these two species indicate that variable thermoregulation likely existed among the non-avian dinosaurs and that not all dinosaurs had body temperatures in the range of that seen in modern birds. 1 Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California 90095, USA. 2 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA.
    [Show full text]
  • Modelling the Abundance of Megaherbivorous Dinosaurs of the Morrison Formation (Late Jurassic, Western USA) James O
    This article was downloaded by: [Dr Daniel Marty] On: 09 October 2012, At: 00:13 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Historical Biology: An International Journal of Paleobiology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ghbi20 Giants on the landscape: modelling the abundance of megaherbivorous dinosaurs of the Morrison Formation (Late Jurassic, western USA) James O. Farlow a , I. Dan Coroian b & John R. Foster c a Department of Geosciences, Indiana-Purdue University, 2101 East Coliseum Boulevard, Fort Wayne, IN, 46805, USA b Department of Mathematical Sciences, Indiana-Purdue University, 2101 East Coliseum Boulevard, Fort Wayne, IN, 46805, USA c Museum of Western Colorado, P.O. Box 20000, Grand Junction, CO, 81502, USA Version of record first published: 21 Jul 2010. To cite this article: James O. Farlow, I. Dan Coroian & John R. Foster (2010): Giants on the landscape: modelling the abundance of megaherbivorous dinosaurs of the Morrison Formation (Late Jurassic, western USA), Historical Biology: An International Journal of Paleobiology, 22:4, 403-429 To link to this article: http://dx.doi.org/10.1080/08912961003787598 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date.
    [Show full text]
  • Body Size As a Driver of Scavenging in Theropod Dinosaurs
    vol. 187, no. 6 the american naturalist june 2016 Body Size as a Driver of Scavenging in Theropod Dinosaurs Adam Kane,1,* Kevin Healy,2,*,† Graeme D. Ruxton,3 and Andrew L. Jackson2,‡ 1. School of Biological, Earth and Environmental Sciences, Cooperage Building, North Mall Campus, University College Cork, Cork, Ireland; 2. School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland; and Trinity Centre for Biodiversity Research, Trinity College Dublin, Dublin 2, Ireland; 3. School of Biology, University of St Andrews, St Andrews, United Kingdom Submitted June 30, 2015; Accepted January 7, 2016; Electronically published April XX, 2016 Online enhancement: appendix. Dryad data: http://dx.doi.org/10.5061/dryad.650c5. q1 abstract: Theropod dinosaurs dominated Earth’s terrestrial eco- large body masses, all of which require large energy inputs. system as a diverse group of predators for more than 160 million One way predators may have offset part of this cost is years, yet little is known about their foraging ecology. Maintaining through opportunistic scavenging on the carrion available a balanced energy budget presented a major challenge for therapods, in such ecosystems. which ranged from the chicken‐sized Microraptor up to the whale‐ Practically all modern predators are known to scavenge sized Giganotosaurus, in the face of intense competition and the when the opportunity arises (DeVault et al. 2003), often demands of ontogenetic growth. Facultative scavenging, a behavior supplementing relatively large proportions of their energy
    [Show full text]
  • Regional Endothermy As a Trigger for Gigantism in Some Extinct Macropredatory Sharks
    RESEARCH ARTICLE Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks Humberto G. Ferro n* Institut Cavanilles de Biodiversitat I Biologia Evolutiva, University of Valencia, Burjassot, Spain * [email protected] a1111111111 a1111111111 a1111111111 Abstract a1111111111 a1111111111 Otodontids include some of the largest macropredatory sharks that ever lived, the most extreme case being Otodus (Megaselachus) megalodon. The reasons underlying their gigantism, distribution patterns and extinction have been classically linked with climatic fac- tors and the evolution, radiation and migrations of cetaceans during the Paleogene. How- OPEN ACCESS ever, most of these previous proposals are based on the idea of otodontids as ectothermic sharks regardless of the ecological, energetic and body size constraints that this implies. Citation: FerroÂn HG (2017) Regional endothermy as a trigger for gigantism in some extinct Interestingly, a few recent studies have suggested the possible existence of endothermy in macropredatory sharks. PLoS ONE 12(9): these sharks thus opening the door to a series of new interpretations. Accordingly, this work e0185185. https://doi.org/10.1371/journal. proposes that regional endothermy was present in otodontids and some closely related taxa pone.0185185 (cretoxyrhinids), playing an important role in the evolution of gigantism and in allowing an Editor: Geerat J. Vermeij, University of California, active mode of live. The existence of regional endothermy in these groups is supported here UNITED STATES by three different approaches including isotopic-based approximations, swimming speed Received: May 4, 2017 inferences and the application of a novel methodology for assessing energetic budget and Accepted: September 7, 2017 cost of swimming in extinct taxa.
    [Show full text]