Friday, April 27, 2012

Karkur Talh: Mom Gets a Break

A Family
Children milking a cow while her calf stands aside
Late Bovidian Period
Courtesy Fliegel Jezerniczky Expeditions (Link)

When I first looked at this image, I could hardly believe my eyes.  Here is a family, with two children milking or suckling a cow.  Any person who has ever been involved in the exhausting process of breast feeding a baby or toddler will "get" this picture. 

It must have been a huge innovation when human beings could get milk for their children from cows, rather than having the sole source of milk coming from the mother or her lactating relatives. Having not yet developed lactase persistence, adults would not have benefited significantly from drinking cow milk.  Yet, the advantage to unweaned children would have been immediate and would have incentivized keeping, rather than eating, friendly wild cows.

The warmth of this picture suggests that the painter wanted to express that the cow was a blessing to his or her family.  It's an extraordinary and timeless picture.


Maju said...

The image is indeed interesting and suggestive. Howvere there are two claims in the second paragraph that I find kinda dubious:

"Having not yet developed lactase persistence"...

Why not? Adaptions are usually not something that evolves with a purpose but something that is there first just randomly and is then found a purpose. If the advantage after this is important, then the adaptive trait will probably become more and more widespread. But evolution always uses what is already there for other reasons or no reasons at all: evolution is NOT intelligent and has no sense of purpose, it just happens.

... "friendly wild cows"...

Domestic cows it looks to me. You don't do that even with some domestic cows today, unless you have a lot of trust (i.e. you are the master): cows have a lot of character and those living in the open tend to be semi-feral, even if also domestic.

But of course the image is impacting and reflects the kind of symbiotic relations that happened with domestication.

Marnie said...

@Maju (Lactase persistence):

Regarding the development of lactase persistence in Africans[The people in these late Bovidian images do appear to look African], see Tishkoff et al, "Convergent adaptation of human lactase persistence in Africa and Europe" (2006):

"We conducted a genotype-phenotype association study in 470 Tanzanians, Kenyans and Sudanese and identified three SNPs (G/C-14010, T/G-13915 and C/G-13907) that are associated with lactase persistence and that have derived alleles that significantly enhance transcription from the LCT promoter in vitro. These SNPs originated on different haplotype backgrounds from the European C/T-13910 SNP and from each other. Genotyping across a 3-Mb region demonstrated haplotype homozygosity extending >2.0 Mb on chromosomes carrying C-14010, consistent with a selective sweep over the past 7,000 years. These data provide a marked example of convergent evolution due to strong selective pressure resulting from shared cultural traits—animal domestication and adult milk consumption."

A selective sweep in the last 7000 years would concur with heightened domestication at the end of the great Wet Phase, something that was pointed out by A. Muzzolini, a French expert on Saharan rock art. See "The Transition to Food Production" post.

Marnie said...

@Maju ("friendly wild cows"):

Regarding the above picture, the cow does look quite domestic. My comment regarding "friendly wild cows" is based on research by Melinda A. Zeder on early domestication. Her studies were based on goats in the Fertile Crescent and the process in Karkur Talh might have been different, but in any case, what she found in her research was that early domestication of goats involved sex selective culling of wild herds to select for smaller milk producing females.

See: Melinda A. Zeder, "Domestication and early agriculture in the Mediterranean Basin: Origins, diffusion and impact" (2008)