DOCSLIB.ORG

The Tortoise Manouria Emys Emys: Behaviour and Habitat in the Wild

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Tortoise Manouria Emys Emys: Behaviour and Habitat in the Wild The tortoise Manouria emys emys: behaviour and habitat in the wild M. Sc. Thesis by Klaus Høybye-Mortensen Supervisor: June 2004 Associate professor, Ph.D. Institute of Biology, Ole Næsbye Larsen University of Southern Denmark Klaus Høybye-Mortensen, University of Southern Denmark, June 2004 ____________________________________________________ Dedicated to the memory of Dr. Annelisa M. Kilbourn The tortoise Manouria emys emys: behaviour and habitat in the wild __________________________________________________ Acknowledgements The author wishes to thank the following organisations and companies for their financial support: Chelonian Research Foundation (Linnaeus Fund), DANCED-SLUSE (TFS-Grant), Internatiotionaliseringspuljen (University of Southern Denmark), HKC-Data, Spejder Sport, Nokia Denmark, MT Contractors, Centrum Skilte, Kosmos Grafisk, Institute of Biology University of Southern Denmark and Institute of Tropical Biology and Conservation, Universiti Malaysia Sabah. Without their support, this project would not have been realised. Thanks to Ole Næsbye Larsen for agreeing to be my supervisor. His patience and help during the whole process has been invaluable to me. Thanks to Frank B. Mortensen for designing and manufacturing the radio telemetry system and assisting in other technological matters. My deepest thanks goes to a long list of people who helped me during my two stays in Sabah: Dr. Datin Prof. Maryati Mohamed for accepting to be my local supervisor, Dr. Annelisa Kilbourn for being a good friend and field colleague, Dr. Edwin J. Bosi for introducing me to this little known tortoise species, Leni Tupang Thomas and the rangers (Makarius, Nimrod, Tinju, Vincent, Francis, Sarinus and Samson) from SOS Rhino for introducing me to jungle life and their help in finding study animals. Thanks to David Gakin, David Antonius, Herman Stawin, Justin, Rayner, Justin and Zul from the Wildlife Department at Tabin Station and their families for taking good care of me. A special thanks to Herman Stawin for inviting me to watch the World Cup 2002 at his house. Thanks to Mike Cadman and the staff at Trekkers Lodge for their care during my stays in Kota Kinabalu. In addition, I would like to thank my fellow students Alan and Jakob for their encouragements and good spirits throughout my university life. Special thanks to Anja for her love and support throughout the project, even though it meant that I had to leave her behind for several months. Thanks to Chuck Schaffer for providing me with “rare” literature pertaining to Manouria emys and his visit in Tabin Wildlife Reserve. Thanks to Betina, Kevin and Chuck for reviewing the thesis and numerous suggestions for improvement. Klaus Høybye-Mortensen, University of Southern Denmark, June 2004 ____________________________________________________ Table of contents i. Landskildpadden Manouria emys emys: naturlig adfærd og habitat ...............................i ii. Abstract ........................................................................................................................... iii iii. Abbreviations ...................................................................................................................iv 1 Introduction.......................................................................................................................1 1.1 The tortoise Manouria emys emys: a biological review ............................................... 1 1.1.1 Distribution......................................................................................................... 2 1.1.2 Morphology ........................................................................................................ 2 1.1.3 Sexual dimorphism and behaviour....................................................................... 3 1.1.4 Nesting ............................................................................................................... 5 1.2 Conservation status..................................................................................................... 6 1.3 Objectives of the present study ................................................................................... 7 2 Methods .............................................................................................................................9 2.1 Research time frame ................................................................................................... 9 2.2 Study area: General description .................................................................................. 9 2.3 Topography .............................................................................................................. 12 2.4 Climate..................................................................................................................... 12 2.5 Flora......................................................................................................................... 14 2.6 Fauna........................................................................................................................ 14 2.7 Recording techniques................................................................................................ 16 2.7.1 Radio telemetry................................................................................................. 16 2.7.2 GPS and GIS..................................................................................................... 18 2.7.3 Home range ...................................................................................................... 19 2.7.4 Daily movements .............................................................................................. 21 2.7.5 Activity............................................................................................................. 21 2.7.6 Diet................................................................................................................... 23 2.7.7 Behaviour ......................................................................................................... 24 2.7.8 Temperature...................................................................................................... 25 2.7.9 Habitat .............................................................................................................. 25 2.7.10 Morphometry.................................................................................................... 26 2.7.11 Statistics ........................................................................................................... 28 3 Results..............................................................................................................................29 3.1 Study animals ........................................................................................................... 29 3.1.1 First sighting ..................................................................................................... 29 3.1.2 Morphometry.................................................................................................... 30 3.2 Diet .......................................................................................................................... 31 3.3 Home Range............................................................................................................. 34 3.4 Activity .................................................................................................................... 43 3.5 Habitat...................................................................................................................... 49 3.5.1 Forest type ........................................................................................................ 49 3.5.2 Temperature and microclimate.......................................................................... 50 3.5.3 Water................................................................................................................ 53 3.6 Nesting behaviour - a case story................................................................................ 55 3.7 Mating- a case story.................................................................................................. 58 4 Discussion ........................................................................................................................60 The tortoise Manouria emys emys: behaviour and habitat in the wild __________________________________________________ 4.1 Study animals and morphometry............................................................................... 60 4.2 Habitat...................................................................................................................... 62 4.3 Temperature preferences........................................................................................... 63 4.4 Diet .......................................................................................................................... 66 4.5 Activity .................................................................................................................... 70 4.6 Home range .............................................................................................................. 72 4.7 Nesting ..................................................................................................................... 75 4.8 Mating ...................................................................................................................... 78 5 Conclusion .......................................................................................................................79
Load more

Recommended publications
  • The Conservation Biology of Tortoises
    The Conservation Biology of Tortoises Edited by Ian R. Swingland and Michael W. Klemens IUCN/SSC Tortoise and Freshwater Turtle Specialist Group and The Durrell Institute of Conservation and Ecology Occasional Papers of the IUCN Species Survival Commission (SSC) No. 5 IUCN—The World Conservation Union IUCN Species Survival Commission Role of the SSC 3. To cooperate with the World Conservation Monitoring Centre (WCMC) The Species Survival Commission (SSC) is IUCN's primary source of the in developing and evaluating a data base on the status of and trade in wild scientific and technical information required for the maintenance of biological flora and fauna, and to provide policy guidance to WCMC. diversity through the conservation of endangered and vulnerable species of 4. To provide advice, information, and expertise to the Secretariat of the fauna and flora, whilst recommending and promoting measures for their con- Convention on International Trade in Endangered Species of Wild Fauna servation, and for the management of other species of conservation concern. and Flora (CITES) and other international agreements affecting conser- Its objective is to mobilize action to prevent the extinction of species, sub- vation of species or biological diversity. species, and discrete populations of fauna and flora, thereby not only maintain- 5. To carry out specific tasks on behalf of the Union, including: ing biological diversity but improving the status of endangered and vulnerable species. • coordination of a programme of activities for the conservation of biological diversity within the framework of the IUCN Conserva- tion Programme. Objectives of the SSC • promotion of the maintenance of biological diversity by monitor- 1.
    [Show full text]
  • New Mexico Geological Society 2019 Spring Meeting Abstracts
    New Mexico Geological Society 2019 Spring Meeting Abstracts TOWARDS UNDERSTANDING THE have led to a stratigraphic nomenclature that by university and museum geologists is confirma- EFFECTS OF ATMOSPHERIC PRESSURE appears to be applicable over a large area of the tion of the ready recognition and utility of these VARIATIONS ON LONG-PERIOD state, from the Sierra Oscura of Socorro County subdivisions in regional stratigraphy, mapping HORIZONTAL SEISMIC DATA: northward to the Sandia Mountains of Bernalillo and economic geology. A CASE STUDY County, a transect of about 150 km. Thus, Mid- Alexis C. B. Alejandro, Adam T. Ringler, David dle and Upper Pennsylvanian (Atokan-Virgilian) C. Wilson, Robert E. Anthony, marine and marginal-marine strata are assigned AN OVERVIEW OF THE ALBUQUERQUE and Sabrina V. Moore to the Sandia Formation (containing a relative SEISMOLOGICAL LABORATORY AND abundance of siliciclastic deposits), the overlying RECENT ADVANCES IN SEISMIC Incoherent noise generated by seismometer tilt Gray Mesa Formation (dominantly carbonate INSTRUMENTATION caused by atmospheric pressure variations often facies), and the Atrasado Formation (alternating Robert E. Anthony, Adam T. Ringler, limits seismological studies utilizing long-period siliciclastic- and carbonate-dominated intervals). and David C. Wilson (>10 s period), horizontal-component seismic A number of intraformational units (members) records. Several case studies have suggested have been identified, with eight members in the The Albuquerque Seismological Laboratory methodologies for correcting these unwanted Middle-Upper Pennsylvanian Atrasado For- (ASL) was established in 1961 in one of the signals using collocated pressure records. However, mation presently recognized. An uninterrupted seismically quietest regions in the country in it is unclear if these corrections are applicable section of the Pennsylvanian System is exposed in order to test seismometers for what is now the to a variety of different geologic settings and Tijeras Canyon east of Albuquerque, NM, along U.S.
    [Show full text]
  • Vol. 25 No. 1 March, 2000 H a M a D R Y a D V O L 25
    NO.1 25 M M A A H D A H O V D A Y C R R L 0 0 0 2 VOL. 25NO.1 MARCH, 2000 2% 3% 2% 3% 2% 3% 2% 3% 2% 3% 2% 3% 2% 3% 2% 3% 2% 3% 4% 5% 4% 5% 4% 5% 4% 5% 4% 5% 4% 5% 4% 5% 4% 5% 4% 5% HAMADRYAD Vol. 25. No. 1. March 2000 Date of issue: 31 March 2000 ISSN 0972-205X Contents A. E. GREER & D. G. BROADLEY. Six characters of systematic importance in the scincid lizard genus Mabuya .............................. 1–12 U. MANTHEY & W. DENZER. Description of a new genus, Hypsicalotes gen. nov. (Sauria: Agamidae) from Mt. Kinabalu, North Borneo, with remarks on the generic identity of Gonocephalus schultzewestrumi Urban, 1999 ................13–20 K. VASUDEVAN & S. K. DUTTA. A new species of Rhacophorus (Anura: Rhacophoridae) from the Western Ghats, India .................21–28 O. S. G. PAUWELS, V. WALLACH, O.-A. LAOHAWAT, C. CHIMSUNCHART, P. DAVID & M. J. COX. Ethnozoology of the “ngoo-how-pak-pet” (Serpentes: Typhlopidae) in southern peninsular Thailand ................29–37 S. K. DUTTA & P. RAY. Microhyla sholigari, a new species of microhylid frog (Anura: Microhylidae) from Karnataka, India ....................38–44 Notes R. VYAS. Notes on distribution and breeding ecology of Geckoella collegalensis (Beddome, 1870) ..................................... 45–46 A. M. BAUER. On the identity of Lacerta tjitja Ljungh 1804, a gecko from Java .....46–49 M. F. AHMED & S. K. DUTTA. First record of Polypedates taeniatus (Boulenger, 1906) from Assam, north-eastern India ...................49–50 N. M. ISHWAR. Melanobatrachus indicus Beddome, 1878, resighted at the Anaimalai Hills, southern India .............................
    [Show full text]
  • Movement, Home Range and Habitat Use in Leopard Tortoises (Stigmochelys Pardalis) on Commercial
    Movement, home range and habitat use in leopard tortoises (Stigmochelys pardalis) on commercial farmland in the semi-arid Karoo. Martyn Drabik-Hamshare Submitted in fulfilment of the academic requirements for the degree of Master of Science in the Discipline of Ecological Sciences School of Life Sciences College of Agriculture, Engineering and Science University of KwaZulu-Natal Pietermaritzburg Campus 2016 ii ABSTRACT Given the ever-increasing demand for resources due to an increasing human population, vast ranges of natural areas have undergone land use change, either due to urbanisation or production and exploitation of resources. In the semi-arid Karoo of southern Africa, natural lands have been converted to private commercial farmland, reducing habitat available for wildlife. Furthermore, conversion of land to energy production is increasing, with areas affected by the introduction of wind energy, solar energy, or hydraulic fracturing. Such widespread changes affects a wide range of animal and plant communities. Southern Africa hosts the highest diversity of tortoises (Family: Testudinidae), with up to 18 species present in sub-Saharan Africa, and 13 species within the borders of South Africa alone. Diversity culminates in the Karoo, whereby up to five species occur. Tortoises throughout the world are undergoing a crisis, with at least 80 % of the world’s species listed at ‘Vulnerable’ or above. Given the importance of many tortoise species to their environments and ecosystems— tortoises are important seed dispersers, whilst some species produce burrows used by numerous other taxa—comparatively little is known about certain aspects relating to their ecology: for example spatial ecology, habitat use and activity patterns.
    [Show full text]
  • MAHS Care Sheet Master List *By Eric Roscoe Care Sheets Are Often An
    MAHS Care Sheet Master List *By Eric Roscoe Care sheets are often an excellent starting point for learning more about the biology and husbandry of a given species, including their housing/enclosure requirements, temperament and handling, diet , and other aspects of care. MAHS itself has created many such care sheets for a wide range of reptiles, amphibians, and invertebrates we believe to have straightforward care requirements, and thus make suitable family and beginner’s to intermediate level pets. Some species with much more complex, difficult to meet, or impracticable care requirements than what can be adequately explained in a one page care sheet may be multiple pages. We can also provide additional links, resources, and information on these species we feel are reliable and trustworthy if requested. If you would like to request a copy of a care sheet for any of the species listed below, or have a suggestion for an animal you don’t see on our list, contact us to let us know! Unfortunately, for liability reasons, MAHS is unable to create or publish care sheets for medically significant venomous species. This includes species in the families Crotilidae, Viperidae, and Elapidae, as well as the Helodermatidae (the Gila Monsters and Mexican Beaded Lizards) and some medically significant rear fanged Colubridae. Those that are serious about wishing to learn more about venomous reptile husbandry that cannot be adequately covered in one to three page care sheets should take the time to utilize all available resources by reading books and literature, consulting with, and working with an experienced and knowledgeable mentor in order to learn the ropes hands on.
    [Show full text]
  • (Manouria Emys) and a Malaysian Giant Turtle
    WWW.IRCF.ORG/REPTILESANDAMPHIBIANSJOURNALTABLE OF CONTENTS IRCF REPTILES & AMPHIBIANSIRCF REPTILES • VOL15, &NO AMPHIBIANS 4 • DEC 2008 189 • 27(1):89–90 • APR 2020 IRCF REPTILES & AMPHIBIANS CONSERVATION AND NATURAL HISTORY TABLE OF CONTENTS FEATURE ARTICLES Only. Chasing in Bullsnakes Captivity? (Pituophis catenifer sayi) in Wisconsin: An Interaction between On the Road to Understanding the Ecology and Conservation of the Midwest’s Giant Serpent ...................... Joshua M. Kapfer 190 Two Threatened. The Shared History of Treeboas (Corallus grenadensis Chelonians,) and Humans on Grenada: an Asian Giant A Hypothetical Excursion ............................................................................................................................Robert W. Henderson 198 TortoiseRESEARCH ARTICLES (Manouria emys) and a Malaysian . The Texas Horned Lizard in Central and Western Texas ....................... Emily Henry, Jason Brewer, Krista Mougey, and Gad Perry 204 . The Knight Anole (Anolis equestris) in Florida Giant ............................................. TurtleBrian J. Camposano, Kenneth (Orlitia L. Krysko, Kevin M. Enge, Ellenborneensis M. Donlan, and Michael Granatosky )212 CONSERVATION ALERT Matthew Mo . World’s Mammals in Crisis ............................................................................................................................................................. 220 . More Than MammalsP.O. ...............................................................................................................................Box
    [Show full text]
  • How Is the COVID-19 Outbreak Affecting Wildlife Around the World?
    Open Journal of Ecology, 2020, 10, 497-517 https://www.scirp.org/journal/oje ISSN Online: 2162-1993 ISSN Print: 2162-1985 How Is the COVID-19 Outbreak Affecting Wildlife around the World? Abdel Fattah N. Abd Rabou Department of Biology, Faculty of Science, Islamic University of Gaza, Gaza Strip, Palestine How to cite this paper: Abd Rabou, A.N. Abstract (2020) How Is the COVID-19 Outbreak Affecting Wildlife around the World? Open The COVID-19 is the infectious disease caused by the most recently discov- Journal of Ecology, 10, 497-517. ered coronavirus at an animal market in Wuhan, China. Many wildlife spe- https://doi.org/10.4236/oje.2020.108032 cies have been suggested as possible intermediate sources for the transmission Received: June 2, 2020 of COVID-19 virus from bats to humans. The quick transmission of COVID-19 Accepted: August 1, 2020 outbreak has imposed quarantine measures across the world, and as a result, Published: August 4, 2020 most of the world’s towns and cities fell silent under lockdowns. The current Copyright © 2020 by author(s) and study comes to investigate the ways by which the COVID-19 outbreak affects Scientific Research Publishing Inc. wildlife globally. Hundreds of internet sites and scientific reports have been This work is licensed under the Creative reviewed to satisfy the needs of the study. Stories of seeing wild animals Commons Attribution International roaming the quiet, deserted streets and cities during the COVID-19 outbreak License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ have been posted in the media and social media.
    [Show full text]
  • N040p017.Pdf
    Vol. 40: 17–29, 2019 ENDANGERED SPECIES RESEARCH Published September 19§ https://doi.org/10.3354/esr00978 Endang Species Res OPENPEN ACCESSCCESS Behavior, growth, and survivorship of laboratory-reared juvenile gopher tortoises following hard release Thomas A. Radzio1,*, Nicholas J. Blase1, James A. Cox2, David K. Delaney3, Michael P. O’Connor1 1Department of Biodiversity, Earth, and Environmental Science, Drexel University, Philadelphia, Pennsylvania 19104, USA 2Tall Timbers Research Station and Land Conservancy, Tallahassee, Florida 32312, USA 3United States Army Construction Engineering Research Laboratory, Champaign, Illinois 61822, USA ABSTRACT: Captive rearing represents a vital component of many conservation and research programs. However, captive animals can exhibit unnatural behaviors and experience high preda- tion following release, which can limit reintroduction success and the inferential value of studies that use released animals. Soft-release measures (e.g. penning) can acclimate individuals and limit interactions with predators but can also require considerable resources. We reared hatchling gopher tortoises Gopherus polyphemus in the laboratory for physiology experiments and subse- quently hard-released them as yearlings to assess the efficacy of this low-cost release method and to explore possible captivity effects on tortoise behavior, growth, and survivorship. Hard-released yearlings exhibited limited dispersal; most constructed burrows soon after release, and, like wild juveniles, exhibited a preference for burrowing under deadwood. Video observations at burrows indicated natural behavior, including overnighting in burrows, extensive basking directly in front of burrows, and limited time away from these important refugia. Basking tortoises responded to simulated predator approach by rapidly entering burrows, with flight initiation distances and hid- ing times equivalent or similar to those of wild individuals.
    [Show full text]
  • Nest Guarding in the Gopher Tortoise (Gopherus Polyphemus)
    148 CHELONIAN CONSERVATION AND BIOLOGY, Volume 11, Number 1 – 2012 Chelonian Conservation and Biology, 2012, 11(1): 148–151 g 2012 Chelonian Research Foundation Nest Guarding in the Gopher Tortoise (Gopherus polyphemus) 1 1 ANDREW M. GROSSE ,KURT A. BUHLMANN , 1 1 BESS B. HARRIS ,BRETT A. DEGREGORIO , 2 1 BRETT M. MOULE ,ROBERT V. H ORAN III , AND 1 TRACEY D. TUBERVILLE 1Savannah River Ecology Lab, University of Georgia, Aiken, South Carolina 29802 USA [[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]]; 2South Carolina Department of Natural Resources, Columbia, South Carolina 29201 USA [[email protected]] ABSTRACT. – Nest guarding is rarely observed among reptiles. Specifically, turtles and tortoises are generally perceived as providing no nest protection once the eggs are laid. Here, we describe observations of nest guarding by female gopher tortoises (Gopherus poly- phemus). Nest guarding among reptiles is considered uncom- mon (Reynolds et al. 2002). Although many crocodilians are known to protect their nests and offspring from potential predators, turtles and tortoises are generally NOTES AND FIELD REPORTS 149 perceived as providing no parental care once the egg around the southeastern United States, have been laying process is complete. However, some tortoise translocated and penned in 1-ha enclosures for at least species have been observed defending their nests from one year to increase site fidelity by limiting dispersal after potential predators, namely the desert tortoise (Gopherus pen removal (Tuberville et al. 2005). One such pen was agassizii; Vaughan and Humphrey 1984) and Asian removed in July 2009, and all tortoises (n 5 14) were brown tortoise (Manouria emys; McKeown 1990; Eggen- equipped with Holohil (Ontario, Canada) AI-2F transmit- schwiler 2003; Bonin et al.
    [Show full text]
  • Chersina Angulata) on Dassen Island, South Africa
    See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/220028468 Sexual disparity in activity patterns and time budgets of angulate tortoises (Chersina angulata) on Dassen Island, South Africa Article in African Zoology · October 2006 DOI: 10.3377/1562-7020(2006)41[224:SDIAPA]2.0.CO;2 CITATIONS READS 13 77 3 authors: Toby Keswick Brian Henen University of the Western Cape 116 PUBLICATIONS 1,379 CITATIONS 7 PUBLICATIONS 40 CITATIONS SEE PROFILE SEE PROFILE Margaretha Hofmeyr University of the Western Cape 87 PUBLICATIONS 664 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Headstarting Agassiz's Desert Tortoises View project Tortoise ecology and conservation View project All content following this page was uploaded by Toby Keswick on 24 July 2014. The user has requested enhancement of the downloaded file. Sexual disparity in activity patterns and time budgets of angulate tortoises (Chersina angulata) on Dassen Island, South Africa Toby Keswick, Brian T. Henen & Margaretha D. Hofmeyr* Chelonian Biodiversity and Conservation – Southern Africa, Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag X17, Bellville, 7535 South Africa Received 13 September 2005. Accepted 11 January 2006 Behavioural frequencies and time budgets for male and female Chersina angulata were recorded in spring, September 2004. The daily activity of the population was 10.51 ± 0.42 h (mean ± CI), but individual males and females were in the open for 2.57 ± 1.12 h and 1.58 ± 1.44 h, respectively. Both sexes spent nearly 3.5 h per day basking with 90% of the basking time in the cover of sparse vegetation.
    [Show full text]
  • Gopher Tortoise Gopherus Polyphemus
    Gopher Tortoise Gopherus polyphemus The Gopher Tortoise is a terrestrial turtle with elephantine hind feet and shovel-like forefeet used for digging impressive underground burrows that can be over 40 feet long and 10 feet deep. The adult carapace (upper shell) is a dark brown or grayish-black and the plastron (lower shell) is yellowish. Age and Size Behavior Diet These slow-growing reptiles may live Gopher Tortoises are most active Gopher Tortoises forage primarily on 40-60 years in the wild. They may reach during the spring and summer months low-growing herbaceous vegetation adulthood between 10-20 years of age and retreat to their burrows during the such as grasses and legumes and will and maturity varies by geographic winter months. They typically do not occasionally eat blackberries and other region within their range. An adult travel far from their burrows to forage seasonal fruits. shell is typically 11 inches in length and and mate if they are in good quality once they reach adulthood, males will habitat and part of a population of develop a concave plastron toward the tortoises. They will spend time basking rear of the shell while the female’s at or near the entrance of their burrow plastron will remain at. Females will and will sometimes dig and use grow slightly larger than males and multiple burrows during the active juvenile tortoise shells usually harden season. at 6-7 years of age. Reproduction Gopher Tortoises may reproduce once they reach maturity What You Can Do To Help between 10-20 years of age.
    [Show full text]
  • The Metabolic Responses of Adult Angulate Tortoises
    CIBTech Journal of Zoology ISSN: 2319–3883 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/cjz.htm 2016 Vol. 5 (2) May-August, pp.61-72/Setlalekgomo and Winter Research Article THE METABOLIC RESPONSES OF ADULT ANGULATE TORTOISE (CHERSINA ANGULATA) TO VARYING AMBIENT TEMPERATURES *Setlalekgomo M.R.1 and P.E.D. Winter2 1Department of Basic Sciences, Botswana University of Agriculture and Natural Resources, Private Bag 0027, Gaborone, Botswana 2Department of Zoology, Nelson Mandela Metropolitan University, Box 77000, Port Elizabeth, 6031, South Africa *Author for Correspondence ABSTRACT Various physiological processes of ectotherms increase with increasing temperature. The effects of varying ambient temperature and gender on the metabolic rate (MR) of adult Chersina angulata were investigated. The tortoises were acclimated to 22 ± 1°C and a 14L:10D photoperiod in an environmentally controlled room prior to MR determination. Oxygen consumption (VO2) rates were determined as index of MR in fasted and resting adult tortoises at eight experimental temperatures (14°C, 18°C, 22°C, 26°C, 30°C, 35°C, 38°C and 40°C). Gender had no significant influence on the MR of C. angulata. MR increased with increasing temperature, but not consistently over the whole range of temperatures tested. MR was strongly temperature dependent, with a Q10 value of 4.13 between 14°C and 26°C. A plateau was detected within a temperature range of 26°C–38°C with a Q10 value of 1.13. The plateau may be a thermal preferendum for C. angulata which may render them advantage to forage at summer temperatures in their natural habitat in the Eastern Cape.
    [Show full text]