Kathy's Commentaries
Frequency of Nursing in
Other Species
by Katherine A. Dettwyler, Ph.D.
Department of Anthropology,
Texas A & M University
Clues as to how often babies should nurse
"naturally" are to be found in how often the offspring of closely related babies
nurse (chimpanzees and gorillas) and the composition of human milk (as frequency of
nursing is related to composition of the milk).
Generally speaking, species that cache their offspring
(leave them alone for hours at a time, like a deer leaving its fawn in the woods hidden,
or a wolf leaving her pups in the den) have milk that is high in protein and fat and low
in carbohydrate. The offspring may be nursed only a few times a day, getting a lot of milk
at any one nursing. The high protein and fat content of the milk make it slow to digest,
and it satisfies the baby's hunger for hours.
Other species are "continuous contact" species,
either by virtual of the fact that the young are precocial (advanced at birth, like a
horse, who can get up and run within the first hour) and can therefore "follow"
the mother all the time (this would include almost all hoofed animals) or because
the young are carried on the mother's body (marsupials, most primates, including humans).
Chimpanzees, gorillas, organutans, and humans all fall in the "carry" category.
And, by the way, chimp and gorilla mothers have to provide active support to the offspring
for several months as they carry them, the babies can cling, but not strongly enough at
first to just hang on all by themselves. Some anthropologists think the very first
"tool" invented by humans was a baby sling. Getting far afield. . .
Continuous contact species have milk that is low in protein
and fat and high in carbohydrates. The offspring tend to nurse very often, but not take
much at any one nursing. The low protein and fat content of the milk make it quick and
easy to digest, and the baby is quickly hungry again, but mom is right there, so it just
nurses again. I have seen figures of 20 minutes as the length of time it takes a breast
milk meal to clear the stomach. Chimp and gorilla babies nurse several times an hour
during the day, and sleep with their mothers at night, so presumably nurse at night also.
>From the composition of human milk, it is clear that
human babies are designed to nurse several times an hour, around the clock. The study of
the nursing patterns among the !Kung you were referring to, where the children nurse
several times an hour for a few minutes each time, is by Melvin Konner and Carol Worthman.
The !Kung do live where it is hot and dry (Bostwana and Namibia), however, frequent
nursing increases the fat content of the milk, rather than the water content, so it isn't
at all clear that the frequent nursing had to do with preventing dehydration. Michael
Woolridge suggested this to me once, when we were working on his chapter for the book, but
there isn't any evidence of it. There is another study of the Gainj people of Papua New
Guinea showing that the children there nurse multiple times an hour, around the clock,
also, and it is hot and humid there, though not as hot as the desert where the !Kung live.
Interesting, among the Gainj, the children do not slow down or taper off the frequency of
their nursing as they get older. I don't have the article here in front of me, but the
figures for nursing frequency are basically unchanged up through the third year.
That said, it is clear that there are many factors affecting
nursing frequency, including what else the mother needs to be doing (Catherine
Panter-Brick has done wonderful research on how breastfeeding fits into a eed tomother's
schedule among two groups of women in Nepal, one group are farmers, the others are
"stay-at-home" moms, as it were), as well as the baby's temperament and
personality. Some babies are very effective nursers and drain the breast of the majority
of its milk in just a few minutes, while others are less effective or less hungry, or just
have a different style, and need 20-40-60 minutes on a breast to get their fill. Some
babies are very good at getting the high fat hind milk -- they are willing to continue
suckling strongly on an almost "empty" breast, and therefore may not be hungry
again so quickly as the child who is less able/willing to nurse this way. I would say that
other than "very frequently day and night" that you absolutely cannot make a
general statement about nursing frequency for human babies that would fit all or even most
of them.
Remember that babies nurse for many reasons other than
nutrition. In fact, Daniel Blackburn and other people who work on the evolution of
lactation think that "lacteal secretions" originated as an antimicrobial
substance to protect eggs in the nest, eventually were ingested by the newly hatched young
and helped establish proper intestinal flora and kill bacteria/viruses/parasites in the
gut, and only "after the fact" were the nutrional components added. All of which
is to say that a child may be nursing because its intestinal flora is out of whack
(manifested as a stomach ache), and it needs the milk to help adjust the intestinal flora.
The child may want/need to nurse because it has been exposed to some pathogen and is
trying to get antibodies, even before any symptoms are apparent to the mother. Nursing
also regulates the child's heartbeat and respiration rate (breathing) and lowers its blood
pressure, so the desire to nurse may be a cry for help with these physiological issues
(see private comment below). And of course, there's always thirst. Remember, too, that
frequency of nursing is how the child helps regulate the mother's milk content and her
fertility, so that clues from the environment about how much good food is available out
there also affect the child's desire to nurse. When there is plenty of other food, and the
child's hunger is satisfied by other foods, and it would be fine for the mother to
wean the child completely and get pregnant again, then frequency of nursing drops off.
When there is very little other food available and the child is meeting most of its hunger
needs at the breast, and it wouldn't be good for either the current baby or the mother to
get pregnant again, then frequency of nursing remains high so that the child gets enough
high-fat milk to meet its needs, and mother's fertility continues to be suppressed.
All of which is to say that different babies in different
circumstances have different needs, but have been endowed by their creator (whether
evolutionary forces or God) to have the ability to communicate those needs even from day
one, by crying. In U.S. culture, the belief that breast milk serves only a nutritional
purpose, and breastfeeding is merely a way of delivering nutrients to a growing organism,
has been a real stumbling block in the way of getting health care professionals and
parents to understand why babies need to nurse so often. I talk about these issues as some
length in my "Beauty and the Breast" chapter. I also have a brief (2-3) page
"article" titled "Breastfeeding: Best for Baby and Easy for Mom" which
I give out to anybody I know who is pregnant. It includes a brief discussion of nursing
frequency. The bottom line is to listen to your baby/child and respond to its needs.
Prepared August 5, 1995.
Last updated March 11, 2004 , by kad. Contents copyright 1999-2004 Sue Ann Kendall and Kathy Dettwyler. Thanks to Prairienet, the Free-Net of east-central Illinois , for hosting this site from 1999 through 2004.
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