Monday, 26 March 2018

Parturition and placentophagy in baboons

Yellow Baboon (Papio cynocephalus) female with young
Wikimedia Commons
Two important papers just appeared on reproduction in baboons (Papio spp.). Natalia Schlabritz-Loutsevitch and co-authors (OA here) describe normal birth and pregnancy complications as observed in the laboratory. Their study was based on imaging (MRI, X-ray, ultrasound) and video recording of deliveries. 

I found it particularly fascinating to see the delivery process. When the baby's head emerges it is face upwards so looking directly at the mother (unlike in humans and chimpanzees where the head emerges face down). After cleaning the baby, the mother ignores it for several minutes and devotes all her attention to eating the placenta. Some of this can be seen in the delivery video (supplementary material here). 

Gesquiere and co-authors (here) summarize no less than 36 years of observations in free-ranging baboons, mainly yellow baboons (P. cynocephalus) from Amboseli in southern Kenya. Their focus is on what determines the interval between births. The main determinant was lactational amenorrhoea due to suppression of the ovarian cycle while the infant was breastfeeding. Once the baby was weaned, most females became pregnant again within 6-8 cycles.

There is an interesting parallel with human hunter-gatherers (previous post). Based on data from the !Kung people of South Africa, Roger Short (here) calculated that a woman in a hunter-gatherer society was pregnant for nearly four years of her life and spent 15 years in lactational amenorrhoea. As a consequence she endured menstrual cycles for rather less than four years. Short contrasted this with present day society where a woman might expect to have menstrual cycles for 35 years of her reproductive life.

1 comment:

  1. The glamorous and Beautiful Independent Escorts in Pakistan Females are the finest high quality Models always attract the Clients . Miss Pinky have attractive figure well-maintained Hot look from up to down. You will be impressed with the most excellent collection of Best Juicy Pakistani Escorts Service Call us We have the best option for sexual fun.