Marmosets are primates that typically give birth to twins. (Image credit: Tambako The Jaguar/flickr, CC BY-ND)
Posted on 01/06/2025 11:28:11 AM PST by BenLurkin
The number of offspring a species has in a litter is phylogenetically conserved, meaning more similar in more closely related species. Deer tend to have one or two offspring, while canids and felids tend to have many more babies in each litter.
Almost all primate species give birth to just one baby, although there are exceptions. Several of the wet-nosed primates — including lemurs, lorises and galagos — and almost all of the marmosets and tamarins from South America give birth to twins.
Marmosets are primates that typically give birth to twins.
(Image credit: Tambako The Jaguar/flickr, CC BY-ND)
Prior to our work, researchers thought these distinctive twin-bearing primates must be what evolutionary biologists call derived, or different, from the more common, ancestral trait. But our research flips that narrative on its head: It's actually the singleton-bearing primates that are derived and distinctive. Further back in evolution, two babies at once was the norm. Our ancient primate ancestors gave birth to twins.
So, when did this evolutionary change in primate litter size occur?
Family tree of mammals surveyed for the study, also known as a phylogeny. The branches of the tree are labeled with colors that correspond to litter size. Darker colors indicate larger litter sizes, while lighter colors (oranges) indicate smaller litter sizes. The animal outlines are, from top to bottom, rodents, rabbits, primates, cetartiodactyls (whales and most hooved animals), carnivores, bats and shrews. (Image credit: Image modified from McBride and Monson, 2024)
(Excerpt) Read more at livescience.com ...
Mankind doesn’t have any “primate ancestors” since the lie of evolution is just that, a lie...
Pure unadulterated crap.
What astonishes me is that people would invest the time to come to what otherwise would be a civil conversation surrounding the topic offered by the OP just to piss in everybody else’s post toasties. Apparently they think this in some bizarre fashion advances their cause when all they’ve really done is put their arrogance, intolerance and ignorance on public view.
A newscaster recently got in trouble for calling an athlete “Most Valuable Primate”.
Looks like a hanging bat.
Thanks BenLurkin.
In Africa, many of the children we fed up at our nutrition center were twins, because as they grew, there wasn’t enough milk for two babies.
Some cultures will kill the weaker of the twins if both are born alive. (twins tend to be premature, so often one or both don’t survive).
When I worked in Africa, in the past, the tribe I worked with considered twins to be cursed and both were killed by the grand mother (if you get thin and die, it is considered you are cursed, and twins often became malnourished and died because there wasn’t enough milk for two babies). But the missionaries would supply milk or take the growing twins into an orphanage where they could be fed (usually the family got them back at age 3 or 4 when they could eat regular food). so the practice stopped.
The reason? First twins often deliver early.
Second, something called twin to twin transfusion where one twin gets more nutrition than the other.
Third: the twins get tangled or have an abnormal lie (sideways).
Four: after the first twin delivers, the second might go sideways and not deliver. Or the placenta might detach from the uterus getting smaller. Or the umbilical cords might tangle up.
Esau and Jacob's delivery in the Bible tells the story of on such delivery. Luckily they must have had a skilled midwife, because it can result in a dead mom and dead babies.
Usually if there is a problem they do a Cesarean section, but in the olden days they would go in and turn the baby to deliver it.
A story from Africa: One of our sisters was called to help with a home delivery that wasn't going well. She delivered baby number one but then a hand came out, and she wasn't sure what to do (she wasn't a nurse but a teacher). So she put the hand back inside, and told the family it was time for her to pray; she went home and checked the books on how to turn the kid around for delivery, and then rushed back and delivered the second baby. It was a boy, who later became a priest and always called her Grandmother....
My grandmother's great-grandmother was a midwife in a village in Europe in the mid-19th century. She didn't deliver my grandmother's twin sisters (she lived in a different village, and was no longer practicing her profession by then--she died about a month after the twins were born).
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