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Placentation and maternal investment in mammals

Barton, Robert�A.; Capellini, Isabella; Venditti, Chris; Barton, Robert A.


Robert�A. Barton

Isabella Capellini

Chris Venditti

Robert A. Barton


The mammalian placenta exhibits striking interspecific morphological variation, yet the implications of such diversity for reproductive strategies and fetal development remain obscure. More invasive hemochorial placentas, in which fetal tissues directly contact the maternal blood supply, are believed to facilitate nutrient transfer, resulting in higher fetal growth rates, and to be a state of relative fetal advantage in the evolution of maternal‐offspring conflict. The extent of interdigitation between maternal and fetal tissues has received less attention than invasiveness but is also potentially important because it influences the surface area for exchange. We show that although increased placental invasiveness and interdigitation are both associated with shorter gestations, interdigitation is the key variable. Gestation times associated with highly interdigitated labyrinthine placentas are 44% of those associated with less interdigitated villous and trabecular placentas. There is, however, no relationship between placental traits and neonatal body and brain size. Hence, species with more interdigitated placentas produce neonates of similar body and brain size but in less than half the time. We suggest that the effects of placental interdigitation on growth rates and the way that these are traded off against gestation length may be promising avenues for understanding the evolutionary dynamics of parent‐offspring conflict.


Capellini, I., Venditti, C., & Barton, R. A. (2011). Placentation and maternal investment in mammals. The American naturalist, 177(1), 86-98.

Journal Article Type Article
Acceptance Date Sep 8, 2010
Online Publication Date Nov 18, 2010
Publication Date Jan 1, 2011
Deposit Date Mar 20, 2015
Publicly Available Date Mar 20, 2015
Journal The American naturalist
Print ISSN 0003-0147
Electronic ISSN 1537-5323
Publisher University of Chicago Press
Peer Reviewed Peer Reviewed
Volume 177
Issue 1
Pages 86-98
Keywords Placenta, Parent‐offspring conflict, Life history, Brain evolution, Reproductive strategies, Gestation.
Public URL
Publisher URL
Additional Information Copy of article first published in The American naturalist, 2011, v.177, issue 1


657435.pdf (873 Kb)

Copyright Statement
©2010 by The University of Chicago

Capellini et al11AN_Appendix.pdf (51 Kb)

Copyright Statement
©2010 by The University of Chicago

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