The Evolution of Human Birth

Francis Maloney (
Sat, 27 Jun 1998 12:10:12 -0400

Jon Krakuer's book Into the Wild gives an interesting account of one man's
attempt to survive on his own in the wild. The story of the last surviving
Yashi of the Sierra Nevada is another example that comes to mind of the
critical need for people to function as part of a social group. The fact
is human beings depend on complex interactions to survive. To take one
attribute of human interdependency and make it out to have evolved by
natural selection isolated from all other social interactions is absurd.

The basic premise of Trevathan's book is that humans have a harder
time giving unassisted birth than other animals do. This should be
substantiated by research, that's what makes it science. And if it is
substantiated that data alone sheds no light on origins.
What facts are given here to work with? What is the data that supports the

1. Breech deliveries occur in 3-4% of all modern human births.
2. ?
please fill in the above blank.

>Trevathan's thesis is that problems relating to human deliveries produced
selective >pressures which led to the nearly universal human practice of
This is a very confusing statement.
Does this mean we evolved compassion, "the human practice of midwifery", to
get our big heads, "problems related to human deliveries", through the
birth canal?
Does the use of the term "selective pressures" imply the development of a
genetic predisposition to assist deliveries?

>Females helping other females birth their offspring, is a
>human type of care that is only rarely seen in other primates.
This sounds like feminist ideology talking here. What is the difference to
the anthropologist between a midwife and a male obstetrician other than sex?

>"At the hominid-pongid divergence, two different adaptive strategies
>developed that had an effect on parturition. The pongids embarked on a
>strategy that emphasized increased adult body size, although the selective
>pressures operating ont hat did not simultaneously favor increases in
>neonatal size. The result was a large pelvis in a large body, a neonate
>that was thus relatively small, and easy parturition." ." ~ Wenda R.
>Trevathan, Human Birth, (New York: Aldine de Gruyter, 1987), p. 22<
This is conjecture unless the relative adult-neonate sizes have been
compared over time.

>Because of this, apes still give birth with babies facing the mother.
Perhaps apes recently evolved this feature. It seems that Trevathan
is building a chain of events to suit her thesis. Wouldn't it have been
easier for pre-humans to have retained this rather than to develop

>When do we see the 'human' pattern of birth presentation? With the
>Australopithecines, we at least see a transitional pattern. Some
>authorities believe that the Australopithecines gave birth with the fetus
>facing the side, others think they had a human birth pattern. <
The phrase "some authorities believe" is so overused in evolutionary
literature it makes me nauseous. Conjecture cannot be used to support a
thesis, at least not in the scientific method I learned.

>Of course we will never know if they helped each other give birth, but
they could have used the help.

I always resent being referred to as a species. To place the study of
human behavior on the same plane as the study of animal behavior is a
deceptive oversimplification based on a false premise. Mankind's identity
is not found in its place as an extension of the animal kingdom. This is
not self elevation it is common sense, for what scientist truly believes
herself to be equal to an animal? The evolutionist says, in false
humility, "the rest of the world better realize they are animals". And in
that very act of definition she proves herself wrong.

Fran Maloney