Mechanics of running of the ostrich (Struthio camelus)

Alexander, R. McNeill; Maloiy, G. M. O.; Njau, R.; Jayes, A. S.

doi:10.1111/j.1469-7998.1979.tb03941.x

Cited by 123 publications

(94 citation statements)

References 15 publications

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“…16g) of fowl claw shows clearly beta-keratin filaments with about 3.5 nm in diameter embedded in a dark (densely stained) matrix [16]. Claws have to transmit and withstand substantial forces during locomotion, and must resist abrasive wear from contact with substrates [261,262]. The mechanical properties of claws have not been studied widely or in detail.…”

Section: Clawsmentioning

confidence: 99%

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Wang

Yang

McKittrick

et al. 2016

Progress in Materials Science

681

474

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a b s t r a c tA ubiquitous biological material, keratin represents a group of insoluble, usually high-sulfur content and filament-forming proteins, constituting the bulk of epidermal appendages such as hair, nails, claws, turtle scutes, horns, whale baleen, beaks, and feathers. These keratinous materials are formed by cells filled with keratin and are considered 'dead tissues'. Nevertheless, they are among the toughest biological materials, serving as a wide variety of interesting functions, e.g. scales to armor body, horns to combat aggressors, hagfish slime as defense against predators, nails and claws to increase prehension, hair and fur to protect against the environment. The vivid inspiring examples can offer useful solutions to design new structural and functional materials.Keratins can be classified as a-and b-types. Both show a characteristic filament-matrix structure: 7 nm diameter intermediate filaments for a-keratin, and 3 nm diameter filaments for b-keratin.Both are embedded in an amorphous keratin matrix. The molecular unit of intermediate filaments is a coiled-coil heterodimer and that of b-keratin filament is a pleated sheet. The mechanical response of a-keratin has been extensively studied and shows linear Hookean, yield and post-yield regions, and in some cases, a high reversible elastic deformation. Thus, they can be also be considered 'biopolymers'. On the other hand, b-keratin has not been investigated as comprehensively. Keratinous materials are strain-rate sensitive, and the effect of hydration is significant.Keratinous materials exhibit a complex hierarchical structure: polypeptide chains and filament-matrix structures at the nanoscale, Progress in Materials Science 76 (2016) 229-318 Contents lists available at ScienceDirect Progress in Materials Sciencej o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / p m a t s c i organization of keratinized cells into lamellar, tubular-intertubular, fiber or layered structures at the microscale, and solid, compact sheaths over porous core, sandwich or threads at the macroscale. These produce a wide range of mechanical properties: the Young's modulus ranges from 10 MPa in stratum corneum to about 2.5 GPa in feathers, and the tensile strength varies from 2 MPa in stratum corneum to 530 MPa in dry hagfish slime threads. Therefore, they are able to serve various functions including diffusion barrier, buffering external attack, energy-absorption, impact-resistance, piercing opponents, withstanding repeated stress and aerodynamic forces, and resisting buckling and penetration.A fascinating part of the new frontier of materials study is the development of bioinspired materials and designs. A comprehensive understanding of the biochemistry, structure and mechanical properties of keratins and keratinous materials is of great importance for keratin-based bioinspired materials and designs. Current bioinspired efforts including the manufacturing of quill-inspired aluminum composites, animal horn-inspired SiC composites, and feather-i...

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Section: Clawsmentioning

confidence: 99%

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Wang

Yang

McKittrick

et al. 2016

Progress in Materials Science

681

474

View full text Add to dashboard Cite

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“…The 3rd toe sustains 105 most of the ground reaction force during locomotion and its claw provides the forces at 106 push-off in fast locomotion. While the 4th toe functions as a lateral support during 107 locomotion (Schaller et al, 2007(Schaller et al, , 2011 Although a large number of studies have been conducted to investigate the ostrich hindlimb 112 kinematics during locomotion (Haughton, 1865;Alexander et al, 1979;Alexander, 1985; 113 Gatesy and Biewener, 1991;Abourachid and Renous, 2000;Jindrich et al, 2007;Rubenson 114 et al, 2004Rubenson 114 et al, , 2007Rubenson 114 et al, , 2010Watson et al, 2011;Smith et al, 2006Smith et al, , 2007Smith et al, , 2010Smith et al, , 2013Schaller et 115 al., 2009Schaller et 115 al., , 2011Birn-Jeffery et al, 2014;Hutchinson et al, 2015), those kinematic analyses 116 were mainly focused on hip, knee and ankle joints. So far, little is known about the relative 117 motions of the 3rd and 4th toes intrinsic joints and the metatarsophalangeal joint during 118 ostrich foot locomotion.…”

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confidence: 99%

Phalangeal joints kinematics during Ostrich (Struthio Camelus) locomotion

Zhang

Luo

et al. 2016

Preprint

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The ostrich is a highly cursorial bipedal land animal with a permanently elevated metatarsophalangeal joint supported by only two toes. Although locomotor kinematics in walking and running ostriches have been examined, these studies have been largely limited to above the metatarsophalangeal joint. In this study, kinematic data of all major toe joints were collected from walking to running during stance period in a semi-natural setup with selected cooperative ostriches. Statistical analyses were conducted to investigate the effect of locomotor gait on toe joint kinematics. The MTP3 and MTP4 joints exhibit the largest range of motion whereas the first phalangeal joint of the 4th toe shows the largest motion variability. The interphalangeal joints of the 3rd and 4th toes present very similar motion patterns over stance phases of walking and running. However, the motion patterns of the MTP3 and MTP4 joints and the vertical displacement of the metatarsophalangeal joint are significantly different during running from walking. This is probably because of the biomechanical requirements for the inverted pendulum gait at low speeds and also the bouncing gait at high speeds. Interestingly, the motions of the MTP3 and MTP4 joints are highly synchronised from slow to fast locomotion. This strongly suggests that the 3rd and 4th toes really work as an integrated system with the 3rd toe as the main load bearing element whilst the 4th toe as the complementary load sharing element with a primary role to ensure the lateral stability of the permanently elevated metatarsophalangeal joint.

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“…After evolving for thousands of years, ostriches have become specialised in running. These nearly 150 kg birds can run steadily for 30 min at a speed of over 60 km/h, with each step longer than 5 m (1,12). In recent years, some researchers have focused on the muscles of the pelvic limb (18), meat (4), long bones (3), supra-jointed toe posture (7), articular cartilage (20), serum glycosaminoglycan and proteoglycan (11), economical bipedal running (16), and toepad from the anatomical perspective (8).…”

Section: Introductionmentioning

confidence: 99%

Macroscopic and microscopic study of integuments on ostrich (Struthio camelus) foot

Zhang

et al. 2016

Journal of Veterinary Research

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Introduction: Ostrich characteristics include fast running, of which the probable enablers have been studied. Yet little research has taken place on one anatomical feature. It is mainly the special integuments on the ostrich foot which facilitate fast running on sand, because as point of direct sand contact they bear the whole weight and provide all the forward force. This study elucidates aspects of the integuments. Material and Methods: A stereo microscope, scanning electron microscope (SEM), and confocal scanning laser microscope were used to observe these integuments. Their surface structure was shown accurately in photographs. An SEM equipped with energy dispersive spectroscopy was used to check element contents of the upper and bottom areas and those on the lateral area of the 3 rd toe. Results: The content of some chemical elements on the upper area (Mg 2.04%, Si 0.18%, P 1.97%, Ca 0.59%, and S 0.69%) was higher than that of the bottom area (Mg 0.14%, Si 0.09%, P 0.10%, Ca 0.28%, and S 0.90%). Zinc was the particular element on the upper area, while sodium, chlorine, and potassium were the specific elements on the bottom area. The parts which must withstand different frictions contained different chemical compounds. Conclusion: The microscopic plane with layer-like structure and stripes may contribute to the wear-resistance of the papillae. The polygonal and prism structures are helpful to fix papillae in a firmer way.

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Mechanics of running of the ostrich (Struthio camelus)

Cited by 123 publications

References 15 publications

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Phalangeal joints kinematics during Ostrich (Struthio Camelus) locomotion

Macroscopic and microscopic study of integuments on ostrich (Struthio camelus) foot

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