Science suggests that, despite popular belief
, human women's menstrual cycles don't necessarily synch up when they live together
. Banded mongoose females, on the other hand, do synch up their reproductive cycles enough that mongoose babies are all born right around the same time
. — Maggie
Your morning dose of weepies — in which a family is formed and loss turns into love. All with the help of science. — Maggie
Fun fact you might not be aware of if you are not the owner of a uterus: Periods go hand-in-hand with pooping
. Not every person who gets a period will end up with diarrhea, but it's not uncommon because the same hormone that makes a uterus contract (a necessary step in the whole period process) can also end up making your intestines contract. Francie Diep explains this effect — as well as the other
hormone-related reason why periods and poops can be linked. — Maggie
Across the United States, politicians are passing laws limiting abortion that are based on the idea that a fetus can feel pain after 20 weeks gestation. But the science underlying this assertion is a lot more complex than it's made out to be
. Most scientists don't think fetuses have the neural circuitry to experience pain until later. And the scientists whose research is most often cited as evidence of fetal pain at 20 weeks don't think their work is saying what anti-abortion activists think it does. — Maggie
Mei Xiang, the female panda who lives at the Smithsonian National Zoo, gave birth today. Above is a screen shot from the Zoo's Panda Cam, showing the baby shortly after birth.
Why should you care about this not-quite-yet-but-soon-to-be adorable baby animal more than you care about any other adorable baby animal? Because the scientific oddities of panda reproduction make its story very interesting.
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Mafeteng Districts Hospital, Lesotho, 1988. A young woman comes in with a stomach ache. Turns out, she's pregnant and in labor. The problem: She has no vagina. Just a uterus, with no path to the outside. So how'd she get pregnant to begin with? Oh, yes. It involves oral sex and a knife fight. — Maggie
"Born in the caul" is a phrase that's connected with a lot of cross-cultural myths and superstitions — babies born in the caul are supposed to be destined for lives of fame and fortune (or, possibly, misfortune and grisly death, depending on which legends you're listening to). Biologically, though, it refers to a baby that's born with part of the amniotic sac — the bubble of fluid a fetus grows in inside the uterus — still attached. Usually, a piece of the sac is draped over the baby's head or face. These are called caul births, and they're rare. But, about once in every 80,000 births, you'll get something truly extraordinary — "en-caul", a baby born inside a completely intact amniotic sac, fluid and all.
There's a photo of a recent en-caul birth making the rounds online. The photo is being attributed to Greek obstetrician Aris Tsigris. It's fascinating. But it's also pretty graphic, so fair warning on that. (If the sight of newborn infants and blood gives you the vapors, you might also want to avoid most of the links in this post, as well.)
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I've been linking Double X Science a lot lately. That's because they're great. It's rare to get such smart, fascinating, science-centered discussion about female anatomy and reproductive issues that goes beyond the surface dressing we all already kind of know. Case in point: This piece by Emily Willingham about the development of the human heart in utero. You've probably heard at one point or another that a fetus' heart starts beating around 6 weeks (an age which is, by the way, calculated from the date of the mother's last period, NOT from the date of actual conception; so the fetus itself is really only about 4 weeks old at this point, and its mother only missed her period two weeks ago). But what's the heart actually like at that point? Turns out, absolutely nothing like what you imagine.
Very cool stuff. — Maggie
In a study of 6,455 semen samples (yup), scientists at Israel's Ben-Gurion University of the Negev found that human sperm were most atheletic — and were found in the highest concentrations — in winter. There was a marked decrease in sperm motility and numbers in spring, summer, and fall
. It's an interesting and logical addendum to the fact that sperm counts and motility decrease in men who subject their testicles to warm conditions; in hot tubs, say, or a pair of overly tight underpants. — Maggie
There is definitely a seasonality to human births, writes Beth Skwarecki at Double X Science. The complicated bit is that human baby season isn't necessarily the same (or as strongly expressed) from place to place and culture to culture. In the United States, significantly more babies are born in July, August, and September. Meanwhile, in Europe, babies seem to make their way into the world in spring. So there's clearly a cultural component to this — but culture doesn't explain it, entirely. Skwarecki's piece explores a messy place where culture, genetics, and circadian rhythms intersect
. — Maggie
This is how the vast majority of sea cucumbers reproduce — by rearing up and releasing a stream of gametes (that is, sperm or eggs, depending) into the water.
WARNING: This video may be considered not safe for work. Especially if you work for or with sea cucumbers.
This is a book about "doin' what comes naturally". Which is to say, sex. But what kind of sex? With whom? And to what purpose? At what point do things like gender expression, sex, reproduction, and child-rearing stop being "normal and natural" and start being something weird that humans do because we are diverse/perverted/sinful/creative (depending on your personal point of view)?
In reality, the word "natural" is mainly how we tell each other which behaviors and traits are the socially correct ones. Calling something natural is often more about specific human cultural standards than it is about what actually happens in nature. Crime Against Nature is artist Gwenn Seemel's attempt to correct that mistake. Filled with gorgeous, Klimt-esque illustrations, Seemel's book shows readers just how diverse nature can be and just how often it fails to conform to our ideas of what is normal — from girls who are bigger and tougher than boys; to boys who give birth; to boys and girls that don't have sex or reproduce at all (and don't seem to mind one bit).
The issues at play here are hefty and potentially uncomfortable, but the book itself is light, playful, and pleasantly un-preachy. It's also set up in a way that allows it to evolve with kids as their reading skills improve — pairing simple statements like "Boys can be the pretty ones" with longer but still easy-to-read paragraphs explaining, for instance, the most recent scientific theories about why male peacocks are so much more colorful than females.
Overall, the book is a great reminder that there are lots of ways to be a girl and lots of ways to be a boy. Nature is chock full of role models for every kid (and every adult). Just because you don't conform to the version of your gender that you see on TV it doesn't mean that you're defective. Last month, my husband and I navigated aisle after aisle of noxiously gendered toys, trying to find things for our niece and nephew that reflected those individual kids, rather than telling them who they were supposed to be and what they were supposed to like. In a world where even Legos come in pink boxes (with instructions for building cute little houses) and blue boxes (with instructions for building race cars), Crime Against Nature is a much-needed breath of fresh air.
You can buy a print version of Crime Against Nature from Gwenn Seemel for $32.
Alternately, you can download the digital version for free (or for a donation of your choice!)
Back in May, I posted about how the Smithsonian National Zoo took another shot at inseminating Mei Xiang, a female giant panda. Female pandas are only fertile once a year, for 24-72 hours, and the zoo had already tried unsuccessfully to get Mei Xang pregnant for eight years in a row. This year, though, they pulled it off, and Mei Xiang gave birth just a little over a week ago. The bad news, which you may have already heard, is that the baby died last weekend. Nobody really knows why just yet.
Reading the stories about the baby panda's death, I noticed that zookeepers had tried to revive the baby using CPR. And that got me curious. Just how, exactly, do you give a panda CPR. At Slate, L.V. Anderson tackles this question. Turns out, the process isn't all that different from resuscitating a human.
CPR is appropriate when a patient’s heart has stopped (whether or not the patient is human), and the goal is to maximize the amount of blood flowing out of the patient’s heart into other vital organs and to get some air into the patient’s lungs so the patient’s blood will be oxygenated. Some animals, including humans and baby pandas, have bodies shaped in such a way that the best way to pump the heart is to directly compress the chest. Other animals, Iike most dogs and cats, have much rounder chests, which makes it harder to directly compress the heart. With these animals, vets recommend compressing the chest from the side, which puts secondary pressure on the heart.
As anyone who’s recently taken a human CPR course knows, the rate of compression recommended for humans is about 100 beats per minute. (Doctors recommend pumping the chest to the beat of the Bee Gees song “Stayin’ Alive.”) The same rate of compression is recommended for animals; even though dogs and cats have a higher resting heart rate than humans do, the rate of 100 compressions per minute gives the heart a chance to refill with blood between compressions.
Read the rest of the story at Slate.com
Via Laura Helmuth
Image: Cheng Du Panda Base, a Creative Commons Attribution (2.0) image from su-may's photostream
Sea urchin egg undergoing mitosis with fluorescent-tagged/stained DNA (blue), microtubules (green).
Cells divide. One single piece of life tugs itself apart and splits in two.
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This is not a geode. It's an animal. An apparently delicious animals with clear blood, whose body is accumulates surprisingly large amounts of a rare metal used to strengthen steel.
This is Pyura chilensis—an immobile ocean creature. Besides the other traits I mentioned, P. chilensis is also capable of both sexual and asexual reproduction. At the Running Ponies blog, Becky Crew explains the results of a 2005 study that detailed the creature's breeding habits for the first time.
The results showed that P. chilensis is born male, before becoming cosexual – having both male and female gonads – in its adolescence as it increased in size. The researchers also found that given the choice – that is, if situated around other individuals – these organisms prefer to breed via cross-fertilisation, writing, “Given that more events of natural egg spawning followed by successful settlement and metamorphosis were recorded in our paired specimens and in our manipulated cross trials … it appears that cross-fertilisation predominates in this species.”
Manríquez and Castilla also found that a greater number of fertilised eggs resulted from the paired specimens, which suggests that cross-fertilisation, or reproducing with another individual, predominates because it is more effective. This assumption was strengthened by the fact that individuals that had cross-fertilised before being put in isolation took at least two months before successfully producing offspring via selfing. However, they were careful to note that while cross-fertilisation was preferred, selfing did not produce inferior offspring. “No perceptible differences in fertilisation, settlement and metamorphosis success among self and outcross progeny were found,” they reported. This suggests that when stuck alone in the ocean, selfing provides an advantageous opportunity for loner P. chilensis individuals to still pass on their genes.
Read the rest of Becky Crew's post to learn more about Pyura chilensis