Please use this identifier to cite or link to this item:
|Scopus||Web of Science®||Altmetric|
|Title:||Biphasic allometry of cardiac growth in the developing kangaroo Macropus fuliginosus|
|Citation:||Physiological and Biochemical Zoology, 2015; 88(2):216-225|
|Publisher:||University of Chicago Press|
|Edward P. Snelling, David A. Taggart, Shane K. Maloney, Anthony P. Farrell, Roger S. Seymour|
|Abstract:||Interspecific studies of adult mammals show that heart mass (M(h), g) increases in direct proportion to body mass (M(b), kg), such that M(h) ∝ M(b)(1.00). However, intraspecific studies on heart mass in mammals at different stages of development reveal considerable variation between species, M(h) ∝ M(b)(0.70-1.00). Part of this variation may arise as a result of the narrow body size range of growing placental mammals, from birth to adulthood. Marsupial mammals are born relatively small and offer an opportunity to examine the ontogeny of heart mass over a much broader body size range. Data from 29 western grey kangaroos Macropus fuliginosus spanning 800-fold in body mass (0.084-67.5 kg) reveal the exponent for heart mass decreases significantly when the joey leaves the pouch (ca. 5-6 kg body mass). In the pouch, the heart mass of joeys scales with hyperallometry, M(h(in-pouch)) = 6.39 M(b)(1.10 ± 0.05), whereas in free-roaming juveniles and adults, heart mass scales with hypoallometry, M(h(postpouch)) = 14.2 Mb(0.77 ± 0.08). Measurements of heart height, width, and depth support this finding. The relatively steep heart growth allometry during in-pouch development is consistent with the increase in relative cardiac demands as joeys develop endothermy and the capacity for hopping locomotion. Once out of the pouch, the exponent decreases sharply, possibly because the energy required for hopping is independent of speed, and the efficiency of energy storage during hopping increases as the kangaroo grows. The right:left ventricular mass ratios (0.30-0.35) do not change over the body mass range and are similar to those of other mammals, reflecting the principle of Laplace for the heart.|
|Rights:||© 2015 by The University of Chicago|
|Appears in Collections:||Aurora harvest 3|
Environment Institute publications
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.