Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Deak FINAL 5 6 2022 with cert.pdf (1.33 MB)

ETD Abstract Container

Abstract Header

A Buff Bradypus or an Elephantine Edentate? Physiological and Ecological Insights into Giant Ground Sloth Integument

Deak, Michael D.
http://rave.ohiolink.edu/etdc/view?acc_num=ysu1651835399349345

Abstract Details

2022, Master of Science in Biological Sciences, Youngstown State University, Department of Biological Sciences and Chemistry.
Remains of megatheres such as Eremotherium spp. and Megatherium spp. have been known since the 18th-century and were among the first megafaunal vertebrates to be studied. While several examples of preserved integument show a thick coverage of fur for smaller ground sloths living in cold climates (i.e., Mylodon and Nothrotheriops), comparatively very little is known about megathere skin. Assuming a typical placental mammal metabolism, it was previously hypothesized that megatheres would have had little-to-no fur as they achieved giant body size and were living in temperate-to-tropical paleoclimates. Critically, however, it is unclear if megatheres had low metabolic rates that are common to extant xenarthrans and if that physiology would impact the amount of fur insulation required to survive in the Pliocene/Pleistocene. Here the “hairless model of integument” is tested using geochemical analyses to estimate body temperature to generate novel models of ground sloth metabolism and paleoclimate with Niche Mapper software. The simulations yielded rates of metabolic activity akin to those of modern xenarthrans and suggest that sparse fur coverage would have resulted in cold stress across all latitudinal ranges inhabited by ground sloths. Overall, Eremotherium favored dense 10mm fur with implications for seasonal changes of coat depth in northern latitudes; Megatherium favored dense 50mm fur year-round in its exclusive range of cooler, drier climates; Mylodon and Nothrotheriops favored full body, dense 50mm fur to approximate full thermal neutrality, matching the remains of both genera, and further implying use of behavioral thermoregulation during the coldest months of the year. With the evidence provided herein, the “hairless model of integument” hypothesis is rejected until a megathere specimen is found with the integument preserved.
Michael Butcher, PhD (Advisor)
Thomas Diggins, PhD (Committee Member)
Ian Renne, PhD (Committee Member)
96 p.
Biology; Paleoecology; Paleontology
Xenarthra; Thermal energetics; Integument; Metabolism

Recommended Citations

Citations

  • Deak, M. D. (2022). A Buff Bradypus or an Elephantine Edentate? Physiological and Ecological Insights into Giant Ground Sloth Integument [Master's thesis, Youngstown State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1651835399349345

    APA Style (7th edition)

  • Deak, Michael. A Buff Bradypus or an Elephantine Edentate? Physiological and Ecological Insights into Giant Ground Sloth Integument. 2022. Youngstown State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ysu1651835399349345.

    MLA Style (8th edition)

  • Deak, Michael. "A Buff Bradypus or an Elephantine Edentate? Physiological and Ecological Insights into Giant Ground Sloth Integument." Master's thesis, Youngstown State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1651835399349345

    Chicago Manual of Style (17th edition)

ysu1651835399349345
252
© 2022, all rights reserved.
This open access ETD is published by Youngstown State University and OhioLINK.