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Mossor FINAL 8 4 2020 with cert(1).pdf (12.73 MB)

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A Horse of a Different Color?: Material Strength and Elasticity of Bones and Tendons in Sloth Limbs

Mossor, Angela
http://rave.ohiolink.edu/etdc/view?acc_num=ysu1597166028044999

Abstract Details

2020, Master of Science in Biological Sciences, Youngstown State University, Department of Biological Sciences and Chemistry.
Vertebrate tissue is highly conservative, and fundamentally, compressive and tensile strength have been observed to be generally similar across taxa despite marked variation in limb posture and locomotor patterns. However, the material properties of limb tissue from arboreal taxa have not been formally evaluated. Sloths are nearly obligatory in their use of below-branch suspensory locomotion and posture, thus placing their limb bones and associated soft tissue structures under routine tensile loading. Suspensory behavior in sloths is associated with low metabolism, body temperatures, and rates of digestion, and thus an extreme need to conserve energy. It is possible that (1) sloth limb bones are modified for enhanced tensile strength and (2) sloths possess a suspensory apparatus’ functionally analogous to that of upright ungulates (e.g., horses); a mechanism that would allow for largely passive support of their body weight while minimizing muscle energy expenditure. The long limb bones from the fore- and hindlimbs of two-toed (Choloepus hoffmanni) and three-toed (Bradypus variegatus) were tested in compression and bending, while their digital flexor tendons were loaded to failure in tension, both by use of an Instron machine to evaluate these hypotheses. Bone strength and elasticity were low in the fore- and hindlimbs of sloths in compression and bending. Sloth flexor tendons also had equally low tensile strength and elastic (Young’s) modulus. Overall, the material properties measured provide support for the hypotheses and match well with predicted function in a tensile limb system. Future studies aim to directly test bones in tension to confirm elevated axial tensile strength. Nevertheless, the results help to explain previous findings in sloth limbs and expand understanding of functional adaptation in mammalian tissue for a range of locomotor/postural behaviors that were previously unexpected.
Michael Butcher, PhD (Advisor)
Mark Womble, PhD (Committee Member)
Thomas Diggins, PhD (Committee Member)
135 p.
Anatomy and Physiology; Animal Sciences; Biomechanics

Recommended Citations

Citations

  • Mossor, A. (2020). A Horse of a Different Color?: Material Strength and Elasticity of Bones and Tendons in Sloth Limbs [Master's thesis, Youngstown State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1597166028044999

    APA Style (7th edition)

  • Mossor, Angela. A Horse of a Different Color?: Material Strength and Elasticity of Bones and Tendons in Sloth Limbs. 2020. Youngstown State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ysu1597166028044999.

    MLA Style (8th edition)

  • Mossor, Angela. "A Horse of a Different Color?: Material Strength and Elasticity of Bones and Tendons in Sloth Limbs." Master's thesis, Youngstown State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1597166028044999

    Chicago Manual of Style (17th edition)

ysu1597166028044999
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This open access ETD is published by Youngstown State University and OhioLINK.