Absence of Placentophagia

Certainty Style Key
Hover over keys for definitions:
True   Likely   Speculative
Human Uniqueness Compared to "Great Apes": 
Absolute Difference
MOCA Topic Authors: 

Placentophagia refers to consumption of the afterbirth by either mothers or – in species with male allomaternal care – males as well. It is almost universal in both carnivorous and herbivorous mammals. Observations of great ape births in the wild are rare, but placentophagia has been observed following some (but not all) births. Placentophagia is observed more routinely among captive chimps and bonobos but apart from recent "new age" contexts is almost never seen in humans, and reports of placentophagia from the ethnographic literature are exceedingly rare. Across human cultures, the placenta tends to be disposed of by burial or some other means in a process that may or may not have ritual significance. 

Placenta and amniotic fluids contain molecules that enhance opioid analgesia. One current hypothesis for the function of placentophagia is pain relief in parturient females. However, the timing, and the fact that in species with cared care non-mothers who did not experience birthpain vie avidly with the mother to grab and consume the placenta point to nutritional benefits or to the role of placentophagia in facilitating the onset of nurturing. It is not known why humans are the exception to the nearly universal practice of placentophagia in mammals.

TIMING OF APPEARANCE OF THE DIFFERENCE IN HOMININ LINEAGE

Probable DisappearanceIt is not known when placentophagia ceased to characterize the line leading to Homo sapiens but the trait appears to be more facultative in other apes than in mammals generally, before fading out almost entirely in the human line, perhaps around 60000K Years ago?

Possible Selection Processes Responsible for the Difference: 
Unknown. There appears to be have been selection for some form of aversion to this practice.

Related MOCA Topics
Timing

Timing of appearance of the difference in the Hominin Lineage as a defined date or a lineage separation event. The point in time associated with lineage separation events may change in the future as the scientific community agrees upon better time estimates. Lineage separation events are currently defined as:

  • the Last Common Ancestor (LCA) of humans and old world monkeys was 25000 thousand (25 million) years ago
  • the Last Common Ancestor (LCA) of humans and chimpanzees was 6000 thousand (6 million) years ago
  • the emergence of Homo ergaster was 2000 thousand (2 million) years ago
  • the Last Common Ancestor (LCA) of humans and neanderthals was 400 thousand years ago
  • the common ancestor of modern humans was 100 thousand years ago

Probable Appearance: 
6000 Thousand Years
Definite Appearance: 
100 Thousand Years
Background Information: 

Placentophagia refers to consumption of the afterbirth by either mothers or – in species with male allomaternal care –sometimes males as well (e.g. in dwarf hamsters and marmosets). It is almost universal in both carnivorous and herbivorous mammals. Placenta and amniotic fluids contain molecules that enhance opioid analgesia. According to a current hypothesis, one function of placentophagia is pain relief in parturient females (Kristal 1991). However, the timing, and the fact that nonmothers who did not experience pain vie avidly with the mother to grab and consume the placenta (e.g. males in some New World monkeys with paternal care), suggest that the main function of placentophagia has to do with facilitating the onset of nurturing (Gregg and Wynne Edwards 2005). This speculation is consistent with the hormone content of placenta (steroids and placental lactogens There have also been suggestions that genetic imprinting involving the Mest gene plays a role in placentophagia in mice but this phenomenon is not yet well documented or understood. 

 

The Human Difference: 

Humans do not routinely engage in placentophagia. Observations of Great Ape births in the wild are rare, but in one birth witnessed for wild gorillas (Stewart 1977 for gorillas) and one of two births witnessed in wild orangs (Galdika 1982), shortly after birth the mother ate the placenta but left the umbilical cord. Placentophagia has been observed more routinely among captive chimps (Marchant 1990) and bonobos. In the case of one parous bonobo mother, the afterbirth was delivered 14 minutes after the baby. The mother “abruptly reaches down to her vagina and pulls out the placenta. She vocalizes and immediately begins to consume the placenta. She continues to emit ‘pleasure’sounds as she eats, holding the placenta with her left hand while cradling (the neonate) and lying on her stomach. She then uses both hands to hold the placenta as she tears off large pieces…” (Bolser and Savage-Rumbaugh 1989). Great Ape placentophagia appears to be somewhat facultative. It is not known what role factors like maternal experience play. After a gorilla birth, the primiparous mother left the placenta behind in her nest. In the second of 2 births observed among wild orangutans, the younger mother (also a primipara) dragged the placenta after her for several days, but did not eat it. Across human cultures, the placenta is usually disposed of by burial or some other means, in a process that sometimes has ritual significance.

 

 

Universality in Human Populations: 

Outside of “new age” contexts in Europe and the U.S., placentophagia is virtually never reported in the ethnographic literature (Hrdy 1999).

 

Mechanisms Responsible for the Difference: 

Unknown.

 

Possible Selection Processes Responsible for the Difference: 

Unknown. There appears to be have been selection for some form of aversion to this practice.

 

Implications for Understanding Modern Humans: 

Iron deficiency is very common in human females, especially those who have borne children. Lack of iron can affect lactation, fertility and ability to be an effective mother. The placenta (said to taste like beef liver is also rich in sources of other nutrients, such as protein. In view of this, it is surprising that even in societies where protein is very limited (e.g. aboriginal New Guinea or Australia), placentophagia is not known to occur.

 

Occurrence in Other Animals: 

Almost Universal in other placental mammals. Marine mammals, camelids, and humans are among the few exceptions.

 

References: 

Bolser, L. and S. Savage-Rumbaugh 1989. Periparturitional behavior of a bonobo Pan paniscus). Am. J. Primat. 17:93-103.

Galdikas, B.M.F. 1982. Wild orangutan birth at Tanjung Putting Reserve. Primates 23(4):500-510.

Gregg, Jennifer and K. Wynne-Edwards. 2005 . Placentophagia in naive adults, new fathers, and new mothers in the biparental dwarf hamster, Phodopus cambelli. Psychobiology 47(20):179-188.

Hrdy, S.B. 1999. Mother Nature: A history of mothers, infants and natural selection. New York: Pantheon.

Kristal, M.B. 1991. Enhancement of opioid-mediated analgesia: A solution to the enigma of placentophagia. Neurosci. Biobehav. Res. 15(3): 425-35.
Marchant, L.F. 1990. Placentophagia in a captive chimpanzee. Am. J. Primat. 20:210.

Stewart, Kelly. 1977. The birth of a wild mountain gorilla (Gorilla gorilla beringei). Primates 18:965-976.