Allometry of the limb long bones of insectivores and rodents

Bou, J.; Casinos, Adriá; Ocaña, Jordi

doi:10.1002/jmor.1051920204

Cited by 64 publications

(73 citation statements)

References 8 publications

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“…In a study comparing skeletal allometry in different carnivoran families with that observed in bovids and certaomorphs, Bertram and Biewener (1990) found evidence for differential allometry across taxonomic groups at different sizes (Fig.·1). In contrast to carnivorans and other small to moderate-sized mammals (Bou et al, 1987;Christiansen, 1999), which scale generally close to geometric similarity, bovids display elastically similar scaling (McMahon, 1975b). Whereas, at extremely large size ceratomorphs scale with increasing skeletal robustness (Prothero and Sereno, 1982) close to static stress similarity (Fig.·1).…”

Section: Scale Effects On the Vertebrate Skeletonmentioning

confidence: 90%

Biomechanical consequences of scaling

Biewener

2005

Journal of Experimental Biology

312

429

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SUMMARY To function over a lifetime of use, materials and structures must be designed to have sufficient factors of safety to avoid failure. Vertebrates are generally built from materials having similar properties. Safety factors are most commonly calculated based on the ratio of a structure's failure stress to its peak operating stress. However, yield stress is a more likely limit, and work of fracture relative to energy absorption is likely the most relevant measure of a structure's safety factor, particularly under impact loading conditions characteristic of locomotion. Yet, it is also the most difficult to obtain. For repeated loading, fatigue damage and eventual failure may be critical to the design of biological structures and will result in lower safety factors. Although area:volume scaling predicts that stresses will increase with size, interspecific comparisons of mammals and birds show that skeletal allometry is modest, with most groups scaling(l∝d0.89) closer to geometric similarity(isometry: l ∝d1.0) than to elastic similarity (l ∝d0.67) or stress similarity(l ∝d0.5). To maintain similar peak bone and muscle stresses, terrestrial mammals change posture when running, with larger mammals becoming more erect. More erect limbs increases their limb muscle mechanical advantage (EMA) or ratio of ground impulse to muscle impulse(r/R=∫G/∫Fm). The increase in limb EMA with body weight (∝W0.25) allows larger mammals to match changes in bone and muscle area (∝W0.72-0.80) to changes in muscle force generating requirements (∝W0.75), keeping bone and muscle stresses fairly constant across a size range 0.04-300 kg. Above this size, extremely large mammals exhibit more pronounced skeletal allometry and reduced locomotor ability. Patterns of ontogenetic scaling during skeletal growth need not follow broader interspecific scaling patterns. Instead,negative allometric growth (becoming more slender) is often observed and may relate to maturation of the skeleton's properties or the need for younger animals to move at faster speeds compared with adults. In contrast to bone and muscle stress patterns, selection for uniform safety factors in tendons does not appear to occur. In addition to providing elastic energy savings, tendons transmit force for control of motion of more distal limb segments. Their role in elastic savings requires that some tendons operate at high stresses (and strains), which compromises their safety factor. Other `low stress' tendons have larger safety factors, indicating that their primary design is for stiffness to reduce the amount of stretch that their muscles must overcome when contracting to control movement.

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Section: Scale Effects On the Vertebrate Skeletonmentioning

confidence: 90%

Biomechanical consequences of scaling

Biewener

2005

Journal of Experimental Biology

312

429

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“…In geometric scaling, all linear dimensions (lengths, diameters) are proportional to (body mass) 1/3 and areas to (body mass) 2/3 . As several authors have observed [52,[54][55][56][57][58][59], adult members of different species are frequently geometrically dissimilar. They are adapted to different ways of life, and geometric similarity may not be consistent with the optimal design for animals of different sizes with different locomotor patterns.…”

Section: Discussionmentioning

confidence: 99%

A Biomechanical Study of the Long Bones in Platyrrhines

Llorens

Casinos²,

Bergé³

et al. 2001

IJFP

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The long bones of 72 individuals of extant platyrrhines, belonging to 17 species (11 genera) were studied by regressions of length, diameters and curvature. Cross-sectional shapes at midshaft and axial and bending strength indicators were also calculated. Results show that forelimb bones scale faster than hindlimb bones, for both length and diameters. Curvature scales faster in the femur than in other bones. Strength indicators showed a high variability in the relative importance of axial and bending loadings. Results are consistent with field observations of locomotor behaviour, mainly as regards quadrupedalism versus suspensory locomotion.

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“…Examples of such allometry have been widely reported for mammals (e.g. McMahon, 1975;Alexander, 1977;Alexander et al, 1979;Prange, Anderson & Rahn, 1979;Biewener, 1983;Scott, 1985;Bou, Casinos & Ocana, 1987;Bertram & Biewener, 1990Christiansen, 1999aChristiansen, ,b, 2002 and birds (e.g. Maloiy et al, 1979;Prange et al, 1979;Alexander, 1983;Gatesy, 1991;Bennett, 1996;Olmos, Casinos & Cubo, 1996;Cubo & Casinos, 1998;Cubo, Menten & Casinos, 1999).…”

Section: Introductionmentioning

confidence: 94%

Scaling of bird claws

2004

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The claw geometry of birds can be used to predict their mode of life. Previous studies, however, have not considered how bird size might affect these predictions. Thus, in the present study, the geometric scaling relationships of bird claws are examined for a variety of extant birds with different modes of life: predatory, climbing, perching or ground-dwelling. Measurements of hind-limb claw radius (i.e. claw size) and claw angle (i.e. claw 'hookedness') of the third digit claw were made on 120 species of bird ranging from 0.0057 kg to 44 kg in body mass. Claw radius was found to be proportional to (body mass) 0.34 across all species. Claw angle was found to increase with body mass for predatory and climbing birds (i.e. bigger birds have relatively more hooked claws), and decrease with body mass for ground-dwelling birds (i.e. bigger birds have relatively less hooked or flatter claws). No significant relationship was found between claw angle and body mass for perching birds. Mode of life could not be predicted with any certainty using measurements of either claw radius or claw angle, suggesting difficulty in assigning fossil species such as Archaeopteryx to a specific locomotor category. As claw design should enable the claw to withstand the forces placed upon it, further work is needed to establish the stresses experienced by the claws of different types of bird.

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Allometry of the limb long bones of insectivores and rodents

Cited by 64 publications

References 8 publications

Biomechanical consequences of scaling

Biomechanical consequences of scaling

A Biomechanical Study of the Long Bones in Platyrrhines

Scaling of bird claws

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