Somewhat OT (and totally random): when do other animals wean?

[mudder17]

This is the insomnia-inducing random question that was keeping my mind whirring last night.

So the way I figure it, the general idea is that most people wean from breastfeeding or formula after the first year, and then slowly make Cow's milk (or other types) and solids the primary source of nutrition. Yes, there are quite a few of us who nurse past the first year, but the general idea is that it no longer becomes a primary source of nutrition.

But let's say that if you take the whole range, most human babies are weaned sometime between 12 months and 5 years (if you want to be generous).

What I was kind of curious is that if you take into account the developmental stage/lifetime of other animals, where do we fall? In other words, when do other animals, particularly other primates, wean their children? At the toddler stage? Younger? Older? What about other non-primates like ... cats or dogs or elephants?

Anyway, just a totally random question and I'm guessing there haven't been any studies done on this, but I was just curious. :)

Eileen

http://www.windsorpeak.com/dc/user_files/33732.gif for Leah
http://www.windsorpeak.com/dc/user_files/33734.gif 27 months...
http://tickers.baby-gaga.com/t/catca...-6_Kaya+is.png
Kaya will be a sister, ~11/14/06!

[Rachels]

I'll have to look this up again. There's stuff about it in Mothering Your Nursing Toddler and I know Kathy Dettwyler has written about it. What I remember is that the *average* age of weaning in humans worldwide is 4.2, and that other mammals all tend to wean around the equivalent time. It has to do with developmental stages more than years, since human years and animal years don't so much line up. Let me look around and see what I can find.

-Rachel
Mama to Abigail Rose
5/18/02
http://www.gynosaur.com/assets/ribbo...ethyst_36m.gif
Nursed for three years!

and Ethan James
10/19/05
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"When you know better, you do better."
Maya

[Rachels]

Here you go, with a few highlights quoted below:

http://kathydettwyler.org/detwean.html

1. In a group of 21 species of non-human primates (monkeys and apes) studied by Holly Smith, she found that the offspring were weaned at the same time they were getting their first permanent molars. In humans, that would be: 5.5-6.0 years.

2. It has been common for pediatricians to claim that length of gestation is approximately equal to length of nursing in many species, suggesting a weaning age of 9 months for humans. However, this relationship turns out to be affected by how large the adult animals are -- the larger the adults, the longer the length of breastfeeding relative to gestation. For chimpanzees and gorillas, the two primates closest in size to humans and also the most closely genetically related, the relationship is 6 to 1. That is to say, they nurse their offspring for SIX times the length of gestation (actually 6.1 for chimps and 6.4 for gorillas, with humans mid-way in size between these two). In humans, that would be: 4.5 years of nursing (six times the 9 months of gestation).

3. It has been common for pediatricians to claim that most mammals wean their offspring when they have tripled their birth weight, suggesting a weaning age of 1 year in humans. Again though, this is affected by body weight, with larger mammals nursing their offspring until they have quadrupled their birth weight. In humans, quadrupling of birth weight occurs between 2.5 and 3.5 years, usually.

4. One study of primates showed that the offspring were weaned when they had reached about 1/3 their adult weight. This happens in humans at about 5-7 years.

5. A comparison of weaning age and sexual maturity in non-human primates suggests a weaning age of 6-7 for humans (about half-way to reproductive maturity).

6. Studies have shown that a child's immune system doesn't completely mature until about 6 years of age, and it is well established that breast milk helps develop the immune system and augment it with maternal antibodies as long as breast milk is produced (up to two years, no studies have been done on breast milk composition after two years post partum).

-Rachel
Mama to Abigail Rose
5/18/02
http://www.gynosaur.com/assets/ribbo...ethyst_36m.gif
Nursed for three years!

and Ethan James
10/19/05
http://www.mothering.com/discussions...smilies/bf.jpg


"When you know better, you do better."
Maya Angelou

[elliput]

Thanks for the cool topic, Eileen, and thanks for the fascinating information, Rachel. So, if I am reading Rachel's selected highlights correctly, humans (following an average mammalian/primate weaning pattern) should wean at the earliest 4 years and optimumly at 6 years. That is definitely food for thought. (sorry, I just couldn't resist :P )

[mudder17]

LOL! You crack me up, as usual! :)

Thanks Rachel! That's very cool. It really does seem like the implication is that the world-wide average weaning age is much closer to what nature/instinct intended. Well, my milk seems to be drying up at the moment, although Kaya is still going twice a day, but it'll be interesting to see if she nurses until the baby is born and if I'll be tandem nursing. So does this mean that most of these animals studied also nurse through pregnancy and also tandem nurse?


Eileen

http://www.windsorpeak.com/dc/user_files/33732.gif for Leah
http://www.windsorpeak.com/dc/user_files/33734.gif 27 months...
http://tickers.baby-gaga.com/t/catca...-6_Kaya+is.png
Kaya will be a sister, ~11/14/06!

[Rachels]

That's a great question. I have no idea. The percentage of human toddlers who wean during pregnancy is very high, which is probably due to a combination of factors: approaching a natural age of weaning, loss of maternal milk supply, and sometimes nursing pain or agitation for mothers. I lost my milk at 12 weeks very abruptly and completely when I was pregnant with Ethan, but Abby continued nursing until 19 weeks. At that point it was really painful and I was soooo ready to stop, but it was a pretty easy transition. She last nursed on her third birthday.

I did read some interesting commentary on Kathy Dettwyler's site about the average age of weaning worldwide. She was saying it's not a very useful statistic because it includes women who nurse for three days and then quit and because societal expectations vary so widely. Interesting.

-Rachel
Mama to Abigail Rose
5/18/02
http://www.gynosaur.com/assets/ribbo...ethyst_36m.gif
Nursed for three years!

and Ethan James
10/19/05
http://www.mothering.com/discussions...smilies/bf.jpg


"When you know better, you do better."
Maya

[elliput]

I was wondering the same thing about tandem nursing. :-)

[Moneypenny]

Fascinating stuff! I am now the family freak because Avery still nurses at 22 months (although I think she's gradually getting ready to wean) and I keep insisting it's perfectly natural. It's nice to see data backing up my instincts!

Susan
mama to my cutie pie, Avery
http://www.gynosaur.com/assets/ribbons/ribbon_emerald_18m.gif[/img][/url]

[m448]

Your milk supply may temporarily drop or change in taste but your toddler could very well continue to nurse. That's what happened with me. I could tell my supply had dropped when I was pregnant with Ryan and combined with Ian's cutting of his 2 year molars he was nursing pretty much all day and night. Once he cut his molars the frequency decreased but he still continued to nurse and even now at 31 months still nurses. He was pretty overjoyed when my milk came in with Ryan and I was glad for him to get colostrum at the tail end of my pregnancy.

[Puddy73]

This is only anecdotal, but some of the cows on our farm tandem nursed. Usually the older calf would be moved to another pen or pasture shortly before the new calf was due, but the older calves would sometimes bawl and break through fences to get to their mother and nurse. Some of the cows would allow their big babies to nurse along with the new baby, and other cows would chase them away. We even had one cow who rejected her new baby to allow the older calf to nurse, even though the older calf was almost as big as she was!


Jennifer
Mommy to Annabelle 9/08/03 & Finn 10/31/05

"If we couldn't laugh, we would all go insane." - Jimmy Buffett