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Female tears affect men’s desire. Photo: wikimedia commons

An old friend told me once that she intentionally cries in conversations with her husband when she’s not getting her way.  She might want to consider a different tactic.  New evidence suggests that a pheromone in women’s tears turns men off rather decidedly.

Two researchers at the Weizmann Institute of Science in Israel have just published a study in the journal Science which demonstrates that the tears of human females turn men off.

Tears contain pheromones, apparently
The researchers, Shani Gelstein and Noam Sobel, have apparently shown that human female tears contain a pheromone that reduces men’s sexual arousal.  A pheromone is a chemical produced by the body that communicates with others of the same species. For example, female dogs in heat have a scent that attracts males. Males of many species have a scent in their urine, or in glandular secretions, that advertises the boundaries of their territories and keeps competitors out.  Pheromones are very common among other mammals but have seldom (if ever) been identified in humans.

It’s interesting that, in this experiment, the subjects could not consciously smell the pheromone. But they apparently smelled it subconsciously, because it affected their behavior.

Women’s tears dampened men’s sexual response
I thought the experiment was ingenious.  The researchers collected a jar of tears from women as they watched sad film clips and tears trickled down their faces. A pad containing either tears or a salt solution that had been trickled down the same faces was then attached to each male subject’s upper lip.  Neither substance had a perceptible odor.  The men were then shown female faces; 17 of the 24 men found the female faces less alluring after whiffing tears than after whiffing salt solution.

Another 50 men showed less physiological sexual arousal after whiffing tears than after whiffing salt solution. Low sexual arousal was indicated by slow breathing rates and low levels of testosterone in their saliva.

In a final experiment, men watched a sad movie while sniffing women’s tears or sniffing a salt solution. The men sniffing tears showed a much reduced blood flow to areas of the brain that had earlier reacted strongly to an R-rated erotic movie.

The researchers don’t know what the chemical nature of the pheromone might be.  More research is need to figure that out.

How would the pheromones in women’s tears affect other women?
I never have really felt that it was to my advantage to cry in front of a man. It might catch attention, might inspire guilt or pity, but I’m not sure it’s ever really worked to my advantage. I’m curious to see the experiment repeated on female subjects.  How do females respond to whiffing the tears of other females? I imagine the response would be increased blood flow to the parts of the brain involved in care-taking, nurturing, and heart-felt sympathy.

What do you think?

Keywords: Shani Gelstein, Noam Sobel, pheromones in tears, women’s tears, tears reduce sexual response

Polar bear. Photo credit: wikimedia commons 

Two-thirds of the world’s polar bears could disappear within 50 years due to greenhouse-gas emissions, said a 2007 report by the U.S. Geological Survey. The bears need Arctic sea ice in order to hunt the seals and other offshore prey that sustain them. But our warming climate is rapidly melting the vital sea ice.  Between 1979 and 2010, Arctic sea ice cover decreased by an average of 11.5% per decade. Due to loss of ice, many bears are starving to death already. The polar bear, Ursus maritimus, is now officially listed as “threatened.”
Polar bear hunting along the edge of sea ice. Photo credit: wikimedia commons

A team of scientists stationed in Alaska may have some tentative good news, though. They just published a new assessment of polar bears’ future in the Dec 16 (2010) edition of the journal Nature. Steven Amstrup, senior scientist with “Polar Bears International,” and his team reported five possible scenarios for greenhouse-gas emissions and ice melting this century. The researchers concluded that Arctic sea ice may not necessarily reach a catastrophic “tipping point” that would lead to an inevitable disintegration of all the ice.  The future of the bears’ ice depends on how much we can limit greenhouse-gas emissions in the years to come and how much we can stabilize the climate. One factor in the bears’ favor is that thinner ice (as it diminishes) becomes more responsive to the cold water below it and can more easily regrow in winter.

Amstrup’s team used climate modeling to predict “sea ice habitability” for the bears over the coming decades, an index that includes the amount of ice over the shallow waters (continental shelves) where seals and other prey hang out, the number of months per year those waters are covered with ice, and the distance between that ice and the more northerly pack ice where polar bears also hunt (there’s a limit to how far polar bears can swim from one ice mass to another).

Polar bear swimming from one pack of ice to another. Photo credit: wikimedia commons

Says Amstrup, “There’s a widely held perception that nothing can be done to help polar bears and the arctic ecosystem. Our findings show this isn’t true. Our findings offer a message of hope but they also underscore the urgent need for reductions in greenhouse gas emissions. ”

For more information about Amstrup’s study and a 2-minute video message from the bear researcher, go to this page on “Polar Bears International.” Or check it out on youtube, called “Hope for Polar Bears” by Steven Amstrup.

Keywords: polar bears Steven Amstrup Polar Bears International bear conservation climate change greenhouse gas emissions global warming Arctic sea ice

Our books on this topic:Veggie Revolution: Smart Choices for a Healthy Body and a Healthy Planet. 2005. Sally and Sadie Kneidel. Fulcrum Books.

Going Green: A Wise Consumer’s Guide to a Shrinking Planet. 2008. Sally and Sadie Kneidel. Fulcrum Books.


Some of my previous posts about how you can reduce greenhouse gas emissions:
Livestock produce 51% of annual worldwide gas emissions

New study: meat impacts climate more than buying local

Less meat….smaller footprint

Is local food the greenest choice?  New study says no

Earth Day: 3 things you can do

Tests performed Saturday food supply found radiation in spinach from farms six 60-75 miles south of Japan’s stricken reactors. Radioactive iodine in the spinach exceeded government safety levels three to seven times, reported food-safety officials. High levels of radioactive iodine are linked to thyroid cancer.

Milk at a dairy 20 miles from the leaking reactors was found on Wednesday to contain small amounts of iodine-131 and cesium-137.

The milk and spinach are from an agriculturally rich area, so the radioactive contamination could affect the food supply for large areas of Japan. Chief Cabinet Secretary Yukio Edano said that more tests are being done on other foods, and if more contamination is found, food shipments from the area will be halted.  He also insisted that the contaminated foods “pose no immediate health risks”.

More than 7,600 people were killed by the earthquake-spawned tsunami that knocked out the nuclear reactors. More than 11,000 people are still missing.

To read more about the food contamination, click here

Keywords: Fukushima Japan nuclear reactors tsunami earthquake

The EPA reported Friday afternoon that a small amount of radiation from Japan’s damaged nuclear reactors has been detected in Sacramento.  Experts have been expecting small amounts of radioactive isotopes to blow over the ocean to California beginning as early as Friday. The isotope picked up by monitors Friday is xenon-133. According to the EPA, the isotope is present in Sacramento at such low levels that it presents no danger to human health.

To read more about the Sacramento story in the LA Times, click here.

Photos of Japan’s crisis from LA Times

Keywords: Japan earthquake tsunami Sacramento xenon-133 radiation spread

Photo by Sally Kneidel

Why are massive snowfalls and cold air walloping the U.S. for the second year in a row?

I listened to the climate reporter for the NY Times, Justin Gillis, on NPR yesterday. He said our current weather is due to a breakdown in the “polar vortex.” Gillis mentioned that the U.S. had warmer winters up through 1995 – thought to be due to global climate change. Now record-setting blizzards are dumping massive amounts of snow over large areas of the U.S. And that too is thought to be due to global climate change. Does that make sense? It does.

This morning I read the newsletter of Thomas Homer-Dixon, a climate scientist in the U.K. He explained what the polar vortex is, how the melting of Arctic ice has changed it, and how that change is responsible for our brutal winter.

Even areas of the South have had multiple snowfalls this year. Photo: Sally Kneidel

What is the “polar vortex”?

Dr. Homer-Dixon explains it this way. Usually in early winter, a basin of low-pressure air forms over the Arctic Ocean’s cold sea ice. Jet streams travel west to east along this basin’s southern edge, creating a huge circular flow – the polar vortex – that travels counterclockwise around the Arctic. This flow acts as a fence, separating the Arctic’s cold air from warmer air farther south.

A warmer Arctic apparently causes colder continents

According to Homer-Dixon and other climate scientists, heat was released last winter (in Dec and Feb) by newly exposed water in the Arctic – water that used to be ice. That heat created bulges of high-pressure air over the Arctic which pressed against the polar vortex, destabilizing it. The jet streams that comprise the polar vortex broke into disconnected segments, some of which traveled north to south, pulling bitterly cold air into North America, Europe and eastern China.

Photo by Sally Kneidel

That change in wind directions is called the “Warm Arctic – Cold Continents” climate pattern.

Scientists can’t say for sure yet whether the same thing is responsible for this year’s brutal winter. But they do know that jet-stream maps for the Northern Hemisphere in late November 2010 showed the jet streams broken into “bits, pieces, loops, and circles with many north-to-south flows over North America and Eurasia.”

Writes Dr. Homer-Dixon, “People who think this winter’s brutish weather proves climate change isn’t real might want to think again.”

Keywords: climate change polar vortex Arctic ice Thomas Homer-Dixon record snow harsh winter


This letter to the editor was written in response to “Scientists connect global warming to extreme rain” (Feb.17) and “Duke earnings up 23% in 2010″ (Feb. 18) 

“Thursday the Observer reported that ‘telltale fingerprints’ in scientific data confirm that manmade climate change is fueling extreme weather events such as massive snowstorms and rainstorms. Friday we learned that Duke Energy’s 2010 earnings were up 23 percent, in large part because of extreme weather.

“Now, Duke Energy wants to raise rates to pay for new coal-fired power plants. Burning coal is a huge cause of the climate crisis. Climate change is not a “victimless crime.” Extreme weather hurts people. But it’s great for Duke Energy.

“Let’s call on Duke Energy to stop fueling the extreme weather that’s driving up our electric bills and Duke’s profits. Duke should shut down some coal plants and promote drastic conservation and energy efficiency.”

Sally Kneidel, PhD

Keywords: Duke Energy coal emissions climate change energy efficiency Duke Energy drives up energy bills Duke Energy drives up coal emissions Duke Energy fuels climate change Duke Energy fuels extreme weather coal fuels extreme weather coal fuels climate change

South African lion taking a break from his kill, a Cape buffalo. Photo: Sally Kneidel

Lions extinct in 10-15 years? That’s the prediction of National Geographic explorers-in-residence Dereck and Beverly Joubert. The couple have studied and filmed Africa’s big cats for more than 25 years. They say that wild lions have declined from 400,000 in 1960 to around 20,000 today.

“The Last Lions”

Based in Botswana, the Jouberts have a new documentary and a companion book, both called “The Last Lions” (see link below). This latest film follows a solitary female lion in the Okavango Delta of Botswana as she tries to feed and protect her three cubs after her mate dies. Female lions usually live and hunt in a group, with a single male as protector against intruding males. A solitary female alone is at a serious disadvantage. Females do virtually all the hunting for a group, and they usually hunt cooperatively.

Males are freeloaders

Males that are part of a pride seldom hunt, but share in the females’ kills. The conspicuous black mane helps protect a male’s neck during fights with rivals, but makes it difficult for him to creep toward pray unnoticed.  Mortality is much higher in males than in females.

Threats to lions

Africa’s lions are threatened primarily by habitat loss, as human populations expand. They’re also frequently poisoned or trapped by rural dwellers who blame lions for livestock losses.

I was surprised at how few lions I saw

I’ve been to South Africa a couple of times in the last 5 years looking for wildlife.  Although I spent virtually all my time in Kruger National Park and other wildlife reserves, I saw very few lions.  In eight weeks of searching, I had only three lion sightings: one solitary male, two males on a kill together, and one pride of females with their young. One wildlife guide I talked with told me that, in his youth 40 years earlier, he had shot lions every single day – to protect his family’s livestock, he said. This was in the same place where I saw only one lion over a period of 3 weeks.

Link to Jouberts on NPR

The Jouberts were interviewed on March 2 by Terry Gross, host of NPR’s “Fresh Air”. Click here to read NPR’s summary of the interview, or to listen to the entire interview.

A couple of my previous posts about Africa’s big cats:

We were lucky to see lions on a kill

Leopard adventure: male and female clash over prey

Keywords: lion extinction lion conservation Dereck Joubert Beverly Joubert The Last Lions NPR

Photo: wikimedia commons

People are good at detecting human personalities accurately, even from expressionless mug shots. A study last year showed that we can reliably tell who is extroverted, emotionally stable, agreeable or imaginative – just from their blank and expressionless faces.

We can read chimps too

A new study shows that we can also predict personality traits accurately from expressionless photos of chimps!  In the new study from Bangor University of Wales, 139 college students looked at pairs of chimpanzee mug shots.  In the photos, the chimps looked straight ahead or at a slight angle with no teeth showing and no shadowing over the eyes which could make them look threatening. Sixty to 70% of the students accurately identified which chimps were dominant and which were not.  Accuracy was better with male chimps than females.

The researchers, led by Robert Ward, say they don’t know exactly what characterizes the face of a dominant chimp or an extroverted person. Ward suspects that chimps can detect the difference too.  He plans to test that next.

Study underscores our genetic similarity to chimps

What’s the significance of these studies? The researchers conclude that the ability to detect important personality traits from facial structure (not expressions) evolved 7 million years ago in a common ancestor of both chimps and humans.  The fact that humans can read chimp facial expressions suggests that this ability is “part of an evolved system.”

Chimps are our closest relatives, sharing 98% of the our DNA. It’s not too surprising that we should able to read their faces in the same way we read human faces.

Wouldn’t it be nice…

I’m always glad when I see a study like this.  I have this fantasy that once we realize how smart and how like us chimpanzees and other great apes are, the tide will turn on protecting our ape relatives from impending extinction.

For more information about what you can do to protect wild apes, see these links to primate conservation NGOs:

Jane Goodall Institute
Orangutan Outreach
Sumatran Orangutan Society
Dian Fossey Gorilla Fund International
Orangutan Land Trust
International Primate Protection League
TRAFFIC:the wildlife trade monitoring network

Some of my previous posts about primates and primate conservation:

Is males’ attraction to trucks and balls genetically based? Jan 14, 2011
Hunting may threaten orangutans even more than habitat loss Dec 6, 2010

Keywords: chimpanzees chimps Robert Ward University of Bangor

African elephants in Kruger National Park. Photo: Sally Kneidel

Just saw a distressing news item.  In an interview published 1/27/11, scientist Ian Craigie says populations of big mammals in Africa have decreased 59% in 40 years. And those figures are only from protected areas such as national parks. If unprotected areas were included in the study, the percent would probably be much higher.  Craigie is a zoologist (University of Cambridge) and former employee of South Africa National Parks.

Craigie says the primary causes of the decline are agriculture, hunting and the bushmeat trade. But all are due to human actions and Africa’s population explosion. Africa’s human population has increased 5-fold since WWII. The additional human population has moved into cultivated areas that were previously wildlife habitat, leading to widespread habitat destruction.

I might add (my words, not Craigie’s) that deforestation for agriculture and timber has increased access to previously secluded or inaccessible wildlife.  Modern weaponry has also increased the ease of killing large numbers of animals for commercial trade as bushmeat or traditional medicine.

White rhino in an African national park. Photo: Sally Kneidel

Craigie says that Southern Africa is better off than West Africa or East Africa because the parks in Southern Africa have better funding and the human population is less dense.

West Africa has the most serious wildlife problem of the three regions because of the strong tradition of hunting for bushmeat, the countries are poorer, and the human population density is high.

What’s the solution? Increase funding for programs to help communities develop livelihoods that depend on protecting wildlife (such as ecotourism) rather than over-harvesting and destroying their greatest resource (wildlife) and their greatest potential for income.  These are my words, not Craigie’s.  Americans alone spend 12 billion dollars per year on ecotourism in Africa.

Keywords: Africa wildlife big mammals elephants rhinos poaching hunting bushmeat population growth deforestation habitat loss 59% loss in 40 years Ian Craigie

Text and photo by Sally Kneidel, PhD

Attaching bands to birds is a longstanding method of studying bird populations. The bands allow researchers to collect data on birds’ movements and longevity.

But scientists have been debating for 30 years whether bands on penguins may hurt the birds.  On aquatic or marine birds, such as penguins, bands are generally attached to the front base of a flipper rather than to a leg.

Note metal band on this African (Jackass) Penguin, on front of left flipper. Photo: Sally Kneidel, southern tip of Africa [click on photo to enlarge it]

Zookeepers noticed as early as the 1970s that flipper-bands can injure molting penguins.  It’s now suspected that bands also create drag when penguins are swimming, which could interfere with prey capture.

A new study published Jan 12, 2011 in the journal Nature provides strong evidence that bands do hurt penguins’ survival and reproduction. Yvon Le Maho of the University of Strasbourg in France and his colleagues banded 50 King Penguins from Possession Island in the southern Indian Ocean. These 50 birds had already been implanted with “minute” and subcutaneous electronic tags. Over the course of a 10-year study, Moho and colleagues found that the banded penguins produced 40% fewer chicks and had a 16% lower survival rate compared to 50 nonbanded penguins

Subcutaneous tags, while safer, are a relatively new technology and not yet widely used in ecological studies.  “Still today you will find that most US studies on Adélie penguins use flipper banding,” says Le Maho.  But his new publication may encourage the increased use of subcutaneous tags instead.

Climate change studies at stake

There’s a wider issue at stake than the birds’ welfare: studies on penguins are often used to gauge the effects of climate change on ecosystems. If a study suggests that a slight warming of ocean waters reduces penguin survival, how much of the difference could actually be due to banding effects?

For the birds and for the sake of our climate data, subcutaneous tags that create no drag should replace flipper-banding in future studies with penguins.

Keywords: penguins, bird banding, flipper banding, climate change, subcutaneous tags

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