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Kangaroo Reproduction

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A presentation on reproduction in kangaroos including embryonic diapause, tyranny of the estrous cycle, and forelimb vs hindlimb development

Kangaroo Reproduction

  1. 1. Saundra SwainImage: images.nationalgeographic.com
  2. 2.  Bifurcated (paired) reproductive tract Lateral vaginae Medial vaginal canal (Feldhamer et al 2007) Image: palaeo.gly.bris.ac.uk
  3. 3.  Kangaroo Choriovitelline placenta Eutherian chorioallantoic placenta Less villi – less surface area- less gas exchange- less gestation time (Feldhamer et al 2007) Kangaroo Eutherian Image: (Feldhamer et al 2007).
  4. 4.  Eutherian: progesterone creates negative feedback loop inhibiting new estrous cycle (Sharman 1970) Image: www.ansci.wisc.edu
  5. 5.  Kangaroo: no negative feedback loop does not inhibit estrous cycle. Short gestation  (Sharman 1970)Image: www.ansci.wisc.edu
  6. 6.  Except grey kangaroo Delayed implantation Egg arrests in blastocyst stage (100 cells) Can be pregnant, have young in pouch and young at foot at same time (Renfree and Shaw 2000, Dawson 1995)
  7. 7. Image: greatunansweredquestions.blogspot.com
  8. 8.  Temporary reduced egg shell Lasts 2/3 of gestation Prevents mother’s immune system from rejecting egg (Dawson 1995)
  9. 9.  Kangaroos have short gestation and longer lactation when compared to Eutherians Kangaroos develop more in pouch (Dawson 1995) Image: www.kangaroocenter.com Image: upload.wikimedia.org
  10. 10.  Can produce 2 different types of milk synchronously Separately controlled mammary gland and teat for young in pouch than for young at foot (Krockenberger 1996; Joss et al 2009; Nicholas 1988)
  11. 11.  Different composition of milk in each teat Four phases of milk production (Krockenberger 1996; Joss et al 2009; Nicholas 1988) Image: 1.bp.blogspot.com
  12. 12.  Forelimbs must develop quickly to be usable for climb to pouch Hindlimbs have more time to develop Forelimbs show much less diversity Hindlimbs show much more diversity (Cooper and Steppan 2010).
  13. 13. Image: brattahlid.tripod.com Image: australianstamp.com
  14. 14.  Cooper, James W., and Scott J. Steppan. 2010. Developmental constraint on the evolution of marsupial forelimb morphology. Australian Journal of Zoology 58: 1- 15. Dawson, Terence J.. 1995. Kangaroos: Biology of the Largest Marsupials. Cornell U. P., Ithaca, New York. Feldhamer, George A., Lee C. Drickamer, Stephan H. Vessey, Joseph F. Merritt, and Carey Krajewski. 2007. Mammalogy: Adaptation, Diversity, Ecology. Third ed. The Johns Hopkins U. P. Baltimore, Maryland. Joss, Janice L., Mark P. Molloy, Lyn Hinds, and Elizabeth Deane. 2009. A longitudinal study of the protein components of marsupial milk from birth to weaning in the tammar wallaby (Macropus eugenii). Developmental and Comparative Immunology 33: 152-161. Krockenberger, Andrew K. 1996. Composition of the milk of the koala, Phascolarctos cinereus, an arboreal Folivore. Physiological Zoology 69(3): 701- 718. Nicholas, Kevin R.. 1988. Asynchronous dual lactation in a marsupial, the tammar wallaby (Macropus eugenii). Biochemical and Biophysical research Communications 154(2): 529-536. Renfree, M.B., and G. Shaw. 2000. Diapause. Annual Review of Physiology 62: 353- 375. Sharman, G.B.. 1970. Reproductive physiology of marsupials. Science 167(3922) 1221-1228.

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