MITCHELL, RM; MAIN, R; BIEWENER, AA; Harvard University: Scaling Patterns in Avian Limb Bone Development

The lengths and diameters of avian limb bone elements increase rapidly throughout ontogeny. Allometric scaling patterns could act to increase material strength or the size of limb elements experiencing greater stresses as mass increases and/or different limbs are used in locomotion during ontogeny. In this investigation, four avian taxa (chickens, ducks, emu, and pigeons) with variable developmental periods and patterns of limb use throughout ontogeny were examined from in ovo to adulthood. In general, most bone elements across the four species exhibited positive allometry (L a D>1.0exp) Data collected on bone length and diameter revealed that the rate of bone development appears to correlate with limb use. For example, leg bone lengths and diameters of ducks increased more rapidly than bone elements of wing; whereas, pigeons and chicken leg and wing bone lengths grew more similarly. Finally, taxa with shorter developmental periods (pigeons vs ducks and chickens) may experience more constrained influences on growth patterns.