Chimpanzee birth similar to humans: study

April 21, 2011 by Deborah Braconnier report
Common chimpanzee in the Leipzig Zoo. Image credit: Thomas Lersch, via Wikipedia.

(PhysOrg.com) -- Published in Biology Letters, researchers led by Satoshi Hirata from the Great Ape Research Institute of Hayashibara Biochemical Laboratories in Japan reveal their findings on chimpanzee births. The researchers were able to observe the live births of three chimpanzees because they had developed a close relationship with the animals.

Hirata and his team had essentially been living with these chimpanzees, even sleeping in the chimpanzee’s enclosures at night in order to be able to witness and capture the births on video. Before this research, no one had witnessed a live chimpanzee , as by nature chimpanzees get nervous at birth and seek isolation. During the births, they observed that, like humans, the babies are born facing away from the mother, or backwards.

While they were witnessing the births, the researchers did not realize what they were about to discover would be something contributing to evolutionary theory. It was not until they had a discussion with a researcher in human childbirth that they discovered what their findings meant.

Back in the 1980s, researchers suggested that a change in birthing position through human revolution was what led to the use of assistance with birth and midwifery. The idea behind this was that because the babies were born backwards, it made it difficult for a mother to pick up and nurture the baby as birth completed.

Witnessing these chimpanzee births, and that fact that they are positioned the same as humans, show that this theory is not the case. Chimpanzees do not require another chimpanzee to assist with the birth, and as observed, they are more comfortable isolating themselves for birth.

Wenda Trevathan, a biological anthropologist from New Mexico State University was the first to suggest this evolution to midwifery. While she never believed it was a necessity, she still believes it was an evolutionary change to something easier. She raises the question now that if the birthing of both humans and chimpanzees is similar, why is it that the have not moved toward having assistance with birth while humans have.

Explore further: Chimps found to be cooperative

More information: Mechanism of birth in chimpanzees: humans are not unique among primates, Biol. Lett. Published online before print April 20, 2011, doi: 10.1098/rsbl.2011.0214

Abstract
Researchers have argued that the process of human birth is unique among primates and mammals in that the infant emerges with its face oriented in the opposite direction from its mother (occiput anterior) and head rotation occurs in the birth canal. However, this notion of human uniqueness has not been substantiated, because there are few comparative studies of birth in non-human primates. This paper reports the mechanism of birth in chimpanzees (Pan troglodytes) based on the first clear, close-up video recordings of three chimpanzee births in captivity. In all three cases, the foetus emerged with an occiput anterior orientation, and the head and body rotated after the head had emerged. Therefore, these characteristics are not uniquely human. Furthermore, in two of the three cases, the chimpanzee newborns landed on the ground without being guided from the birth canal by the mother. The fact that the human newborn emerges with an occiput anterior orientation has thus far been taken as evidence for the necessity of midwifery in modern humans, but this view also needs revision. Our observations raise the need to reconsider the evolutionary scenario of human birth.

Related Stories

Chimps found to be cooperative

March 4, 2006

In a series of experiments, researchers in Germany have found that chimpanzees work cooperatively to help each other accomplish a goal.

Study: Caesarean babies more likely to die

September 7, 2006

A U.S. study finds babies born by Caesarean section are nearly three times more likely to die during the first month of life than those born naturally.

Humans and chimpanzees, how similar are we?

November 20, 2006

The DNA sequences of humans and chimpanzees are 98.5 percent identical, but now Uppsala University researchers can show that parts of the genetic material are missing in one species or the other.

Human-like altruism shown in chimpanzees

June 25, 2007

Debates about altruism are often based on the assumption that it is either unique to humans or else the human version differs from that of other animals in important ways. Thus, only humans are supposed to act on behalf of ...

Do you want fries with that, Mickey?

January 30, 2008

Using mice as models, researchers at the Max Planck Institute for Evolutionary Anthropology traced some of the differences between humans and chimpanzees to differences in our diet. The findings appear in the January 30 issue ...

Chimpanzees respond to infant death nearly same as humans

February 3, 2011

(PhysOrg.com) -- For the first time, researchers of the Max Planck Institute for Psycholinguistics in the Netherlands report in detail how a chimpanzee mother responds to the death of her infant. The chimpanzee mother shows ...

Recommended for you

Genomes uncover life's early history

August 24, 2015

A University of Manchester scientist is part of a team which has carried out one of the biggest ever analyses of genomes on life of all forms.

Rare nautilus sighted for the first time in three decades

August 25, 2015

In early August, biologist Peter Ward returned from the South Pacific with news that he encountered an old friend, one he hadn't seen in over three decades. The University of Washington professor had seen what he considers ...

Why a mutant rice called Big Grain1 yields such big grains

August 24, 2015

(Phys.org)—Rice is one of the most important staple crops grown by humans—very possibly the most important in history. With 4.3 billion inhabitants, Asia is home to 60 percent of the world's population, so it's unsurprising ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.