“What nonsense! Does anybody realize that the polar bear population has increased from 5,000 in 1972 to 25,000 today! To be put on a threatened or endangered list, shouldn’t the numbers be declining???”

This, from blog reader Vince, was a recurring theme among the hundreds of responses to yesterday’s decision to list the polar bear as a threatened species under the U.S. Endangered Species Act.

I’d seen this number cited before, but I’d never seen any attribution as to its source. After some web research, conversations with polar bear researchers, and some help from a longtime journalist who specializes in animal/wildlife stories, here’s what we could find.

The number has some basis in fact, but is misleading: If polar bears have built in numbers since the 1970’s, it probably had a lot more to do with hunting bans than any aspect of global warming.

Polar Bear habitat covers five nations: The U.S. (Alaska), Russia, Canada, Denmark (Greenland), and Norway (the Spitsbergen and Jan Mayen Islands). Those five nations, along with the International Union for the Conservation of Nature, took a stab at guesstimating worldwide polar bear populations in the early 1970’s. For example, based on observer reports from Arctic villages, ships, and other sources, U.S. researchers came up with an estimate of 18,000 polar bears throughout the Arctic. The Canadian Wildlife Service set the number at 20,000. The Soviet Union submitted the low bid, estimating a worldwide population of 5,000 animals. In late 1973, the five polar bear nations signed the International Agreement on the Conservation of Polar Bears, and agreed to go with the lower Soviet estimates in order to wrap up a wildlife agreement that was unheard-of during the Cold War years.

Whichever of these estimates may have been closer to the real number is still unclear. It’s generally believed that polar bear populations did grow after the treaty was signed — but it had nothing to do with the Arctic climate: The Treaty also set restrictions on trophy hunting for the big bears — outlawing the then-common, controversial practice of hunting polar bears by helicopter. The U.S. had already banned all but some native subsistence hunting the previous year, through the US Marine Mammal Protection Act.

But there’s another revealing number from that year: Merritt Clifton, the editor of Animal People , dug through online newspaper archives and discovered this tidbit: Canada was the last Arctic nation to curtail large-scale hunting of polar bears. According to a 1973 United Press International story, Canada’s Northwest Territories allowed a quota of 422 bears to be killed that year.

So let’s do the math: If the 5,000 number were correct, they authorized the killing of nearly 10% of the world’s polar bear population — In just one part of Canada’s polar bear habitat, and in just one year. It’s very difficult to accept that a global population of only 5,000 could have sustained that rate of loss.

More recent polar bear research suggests that any growth in worldwide population has likely stopped, and that the bears themselves are generally thinner and give birth to fewer young. Here’s the key USGS paper on the bears’ status in the U.S. part of their habitat. The current estimates for global polar bear population is between 22,000 and 25,000 — numbers too big to risk any immediate extinction. But the overwhelming amount of research on polar bear health and future prospects says they’re in for a rough ride in the next fifty years.

One credentialed, dissenting scientist is Dr. Mitchell Taylor, a researcher who did much of his work on behalf of Canada’s Nunavut Territory. Taylor has acknowledged that climate change is impacting polar bears, but he does not see a great risk of collapse of the species. The recently-retired Taylor has researched bear populations in the Davis Strait, between Canada and Greenland. Taylor is due to publish his results later in the year, and in newspaper interviews, he has said that bears in the region are healthy in both size and number. Critics point out that Nunavut, Dr. Taylor’s longtime employers, have a huge stake in what remains of the legal polar bear trophy-hunting business, estimated to be a $2 million business for impoverished Nunavut communities. Yesterday’s US decision to declare the bears as “threatened” will dry up a longstanding loophole: U.S. trophy hunters were barred from killing bears in the U.S. (Alaska), but prior to the ruling, could still obtain permits to hunt polar bears in Canada and import the trophies.

-Peter Dykstra, Executive Producer, CNN Science Tech & Weather

U.S. Interior Secretary Dirk Kempthorne announced that the polar bear will receive protection as a “threatened” species under the U. S. Endangered Species Act. Conservation groups had petitioned the U.S. to give protection to the mammals — citing a rapid decline in Arctic sea ice, and U.S. government studies predicting a rapid decline for the bear population due to loss of habitat. The government was under federal court order to rule on the bears’ status by tomorrow.

CNN.com will have full details soon.

-Peter Dykstra, Executive Producer, CNN Science & Technology

If so, you might want to check this page on the U.S. Geological Survey’s site.  USGS has tagged ten walruses in the Bering Sea, and is following the enormous mammals to check on feeding habits.

Walruses are not currently listed as an endangered species under US law, but the US is considering a petition to protect them.   Hunting of walruses is outlawed under the US Marine Mammal Protection Act, with certain exemptions given to traditional native hunters.

Okay, here’s a challenge for loyal readers of the SciTechBlog:  Based on past performance, some of you will see this as valid research on a keystone marine species; others of you will see it as a waste of federal taxpayer dollars.   And at least one of you will make a bad joke about the John Lennon “Walrus” song.   So let ‘er rip……..

But whatever you may think of this, USGS is offering you a chance to hunt for sea otters.  Hunt for them in a photo, that is:

Southern Sea Otters tend to hang out in blobs of brown sea kelp.   The problem is that a brown sea otter, lolling around in a kelp bed, looks a lot like a blob of brown sea kelp itself.    There are four of them in the picture at this link, taken by USGS Researcher Brian Hatfield.   Click on the photo to see the location of the otters revealed. 

Peter Dykstra     Executive Producer     CNN Science, Tech, and Weather

A federal judge says enough is enough — no more delay.  The Interior Department now has just 16 days to issue a decision on whether to list the polar bear under the Endangered Species Act because of global warming.

 The government was supposed to announce that decision by January 9.  But the Fish and Wildlife Service said it needed another month to make the complex listing more easily understood.  However, that month came and went, and environmental groups sued, leading to yesterday’s court ruling.

U.S. District Judge Claudia Wilken agreed with the conservation groups — the Center for Biological Diversity, the Natural Resources Defense Council, and Greenpeace — that Interior missed the deadline.  And she disagreed with a government request for another delay, ordering a decision be announced by May 15.

Judge Wilken ruled that Interior has been violating the Endangered Species Act for four months by missing the Jan. 9 deadline, and said the government has not offered sufficient justification for that delay, much less further delay. Interior has said it needed until June 30 to finish a legal and policy review of the proposed listing.

Environmentalists say they think the government is delaying the decision to make it easier for oil companies to get offshore oil leases in the Chukchi Sea, prime polar bear habitat.

The Fish and Wildlife Service proposed the ESA listing in December of 2006 because climate change is shrinking polar bear habitat.  Some scientists predict summer sea ice in the Arctic will disappear by 2030.  A U.S. Geological Survey study estimated that polar bears in Alaska could disappear by 2050.

Diane Hawkins-Cox    Senior Producer  CNN Sci-Tech

Not everyone in the animal kingdom needs to have sex to reproduce, but asexual species tend not to last as long as sexuals because, as the theory goes, asexuals are more susceptible to accumulating harmful mutations over many generations. That is why scientists are so fascinated by the Amazon molly fish, whose longevity has mysteriously defied evolutionary expectations.

This fish species consists of only females and, in fact, was the first unisexual vertebrate species ever discovered. The Amazon molly lives in a small range from the Nueces River in southeast Texas to the mouth of the Rio Tuxpan in Mexico. There are well over 100,000 alive today, and there are no signs that their fertility is less than that of their sexual sister species, said biologist Laurence Loewe at the University of Edinburgh.

While Amazon mollies do not reproduce sexually, their eggs can only begin developing when triggered by sperm from males of related species. Scientists think the Amazon molly probably evolved as an asexual species about 70,000 years ago.

Loewe and collaborator Dunja Lamatsch at the University of Wuerzburg, now at the Austrian Academy of Sciences, applied mathematical models to the Amazon molly’s genetic history, and found that the species should exist for less than 20,000 years before becoming extinct. The models examined a concept called Muller’s ratchet, which assumes asexual populations tend to accumulate harmful mutations over time that lead to extinction. They recently published their findings in BMC Evolutionary Biology.

Since the species is probably much older than 20,000 years, this creates what scientists call a genomic decay paradox. How, then, could the species have defied evolutionary models, and survived so long?

One mechanism at work to help the fish survive may be what is called “paternal leakage” of undamaged DNA. In other words, when sperm from males of other species trigger egg development in the Amazon molly, DNA may occasionally leak to the female and repair or restore genes gone awry through mutations. Further research is needed to determine if this or still other processes slow down the extinction predicted by Muller’s ratchet.

The results could have implications for the conservation of other so-called ancient asexuals, which include one species closely related to the Amazon molly.

Amazon mollies are also at a disadvantage because sailfin mollies, their parental species, prefer to mate with females of their own species rather than giving sperm to the Amazon mollies, research from Texas State University shows. Sailfin mollies also produce more sperm before mating with sailfin females than with Amazon mollies.

“Our results suggest that Amazon mollies have it doubly hard; they both have limited genetic variation (as per the paper above) and males of their parental species generally avoid mating with them and providing them with sperm,” said Caitlin Gabor, associate professor of biology. “Yet, they clearly have persisted for a long time and possibly longer than any other vertebrate asexual species.”

–Elizabeth Landau, Associate Producer, CNN.com

As Romeo and Juliet disputed whether they heard a lark or a nightingale singing on the pomegranate tree, they probably did not ponder the biological underpinnings of why birds sing in springtime.

In fact, the precise mechanisms for springtime bird singing have always been mysterious to scientists. But a recent study breaks new ground in the biology of bird songs.

A group of researchers has discovered a hormone that sets off neural activity that causes birds to sing when the days get longer. The study, led by Takashi Yoshimura of the Nagoya University, Japan, was reported in a recent issue of the journal Nature.

The scientists studied 38,000 genes of male Japanese quails under both long and short days. They found that some genes were only switched on 14 hours after dawn on the first long day.

These particular genes were found only in cells on the surface of the hypothalamus, and produced a thyroid-stimulating hormone, said Peter Sharp, a collaborator on the study at the Roslin Institute in Scotland. This hormone sets off the release of another hormone which stimulates spring breeding, he said in an e-mail.

The pituitary gland gets a boost from the hormone, pumping out other hormones that make the birds’ testes grow, the study said. This process makes birds sing.

But it’s not just our fowl friends that could benefit from this study. Human conditions such as seasonal affective disorder and poor fertility could be connected to a malfunction of the very same cells studied in the birds, Sharp said.

“Discoveries in basic biology increase the chances of developing new ways of improving animal and human well being,” he said.

–Elizabeth Landau, Associate Producer, CNN.com

Apparently a few hundred million of you were zoned out the day your a) mother b) father c) elementary school teacher told you that if you make a mess, you clean it up. And it appears that the smokers of the world had a higher absentee rate than others.

Volunteers on coasts and lakes picked up more than six million pounds of bottles, bags and butts last September 15, during The Ocean Conservancy’s annual International Coastal Cleanup. The organization has just released a detailed analysis of the litter they picked up along 33,000 miles of shoreline.

Top 10 debris items collected worldwide:

• cigarette filters 27%
• food wrappers/containers 9%
• caps lids 9%
• bags 8%
• beverage bottles (plastic) 6%
• cups plates forks knives spoons 5%
• glass bottles 4%
• cigar tips 4%
• straws/stirrers 4%
• beverage cans 4%

The most dangerous items to ocean creatures: plastic bags, balloons, fishing traps, fishing line, and six pack beverage holders. Volunteers also found condoms, diapers, syringes, light bulbs, shotgun shells, and appliances.

Some of the 378,000 volunteers in 76 countries learned firsthand how deadly trash can be to wildlife. Those scouring beaches found 81 birds, 63 fish, 49 invertebrates, 30 mammals 11 reptiles and one amphibian entangled in debris during the cleanup effort. Among the volunteers were 8300 divers, who averaged 20 pounds of trash each.

Data collected in earlier beach cleanups has helped craft marine debris legislation, and helps find simple answers to litter problems.

“It’s a wonderful event, engaging people to do something positive,” said Laura Capps, Senior Vice President of the Ocean Conservancy. “It also gives us tangible data to identify sources and problems,” she said.

Many of the answers to reducing coastal litter do NOT involve rocket science.

Capps said 80% of the beach trash comes from land based sources. And solutions may be as simple as providing more bins on beaches for people to put their picnic litter.

So what about the other 364 days a year when volunteers are not cleaning up?

Sometimes the volunteers who pick up trash on the official cleanup day get active in their communities to make beach beautification a year-round effort.

“For many people the ocean is big and vast and dark, out of sight and out of mind,” said Capps. She said people who say they would never leave trash at the beach don’t realize that flicking a cigarette out the window or not chasing down a straw wrapper from their kids are creating litter that can just as easily end up in a waterway.

One of the sponsors of the coastal cleanup is a company whose products make up a big part of the trash problem.

Paige Magness, spokeswoman for Philip Morris, said there are simple answers to reducing some cigarette trash.

She said the cigarette manufacturer works with the national non-profit Keep America Beautiful organization to place cigarette receptacles at the entrances of non-smoking buildings. In 2007, she said that effort reduced cigarette litter by 54% in the 180 participating communities.

Cans and bottles also make up a big part of ocean trash. Coca-Cola has been working with the Ocean Conservancy and its cleanup efforts for 12 years.

“We have an extensive research and development program, we are always looking at the next innovation in packaging,” said Lisa Manley, Director of Environmental Communications at Coke headquarters in Atlanta.

She said the company was among the first to use recycled content, and to invest on “bottle to bottle” facilities, taking used plastic and turning it into new bottles.

The Ocean Conservancy says it wants to stress the positive aspect of hundreds of thousands of people making a difference in cleaning up coastal areas.

And maybe some of those “things you should have learned in kindergarten” need a little review. It could be your bottle or your cigarette butt responsible for killing some of the million seabirds and 100,000 marine mammals and turtles that die from eating or becoming tangled in marine trash every year.

–Marsha Walton, Producer, CNN Science and Technology

We all know one fish and one fish make two fish, but recent evidence suggests that fish may know that too. In fact, mosquitofish can count up to four, according to results from a team of researchers led by Angelo Bisazza of the University of Padua in Italy.

In each test, a lone female mosquitofish had two options for shoals to join, each containing between two and eight other fish. The results showed the lone fish would usually choose the shoal that was larger by just one fish, consistently picking the shoal of four fish over the one with three, and the shoal of three fish over the one with two.

But when one of the choices was larger than four fish, the fish could no longer discriminate. Monkeys and one-year-old children exhibit the same limit, Bisazza said.

Experiments examining what the fish would do when confronted with larger numbers found that, for shoals of more than four fish, they could still tell the difference between the quantities if there was at least a 2:1 ratio. That is, they would choose a shoal of eight fish over the one with four, but they could not discriminate between a shoal of 12 and a shoal of eight. These results are consistent with mathematical abilities observed in birds and mammals.

Similar performance has also been observed in people who speak languages that contain limited vocabularies for numbers, Bisazza said. For instance, speakers of the Amazonian language Munduruku only have words for numbers from one to five, and do not have names for numbers beyond that. Though they are able to solve nonverbal number tasks involving quantities up to 70, in exact arithmetic they do not do well with numbers larger than four or five, he said.

Besides fish, other non-human creatures that have shown at least some rudimentary mathematical abilities in studies include chimpanzees, macaques, dolphins, dogs, parrots and pigeons.

“Many researchers are now convinced that mammals and birds may share common mechanisms to count objects and compare quantities,” Bisazza said.

–Elizabeth Landau, Associate Producer, CNN.com

Animals may not model swimsuits, but they still need to avoid becoming overweight. Zoos are getting savvier about nutrition for their captive wild animals, coming up with more ways to curb obesity and related problems like diabetes and cardiovascular disease.

The Brookfield Zoo outside Chicago puts gorillas like these on a diet system like Weight Watchers, staff nutritionist Jennifer Watts told CNN affiliate WLS. Each food item has a specific point value attached, and animals have limits for how many points they can accumulate. A gorilla gets two points for a cube of sugary fruit juice, while a polar bear gets one point for each of its beloved granola bars.

Zoo Atlanta doesn’t use an official point system, but strives to provide a low-calorie, healthy diet for its animals too. This zoo has moved away from fruit juices for primates - now their orangutans and gorillas get Crystal Light. It may have less sugar, but they like the low-calorie alternative just as much, the zoo’s senior veterinarian Dr. Maria Crane said in an interview for this blog.

Zoo animals have a particular risk for becoming overweight because they do not have to forage or hunt for food the way they would in the wild, Crane said. To encourage the animals to move about, zoo staffers put food in the enclosed habitats such that the animals have to go forage for it.

“As we use food for enrichment also, it not only contributes to physical needs of animal but also psychological needs,” she said.

The same principles for people who are maintaining good body condition go for animals, such as “balance consumption with activity,” she said.

The field of zoo nutrition is evolving, and zoos are receiving more information about what animals eat in the wild.

When plants and fruits from an animal’s native habitat aren’t available, Zoo Atlanta tries to provide substitutes that are as similar as possible.

“You don’t find fruit juice stands in the wild,” she said.

-Elizabeth Landau, Associate Producer, CNN.com

A robotic spy plane currently under development would be perfect for Batman – that is, if he were smaller than a paper clip.

Source: Eric Maslowski, research computer specialist in the University of Michigan 3D Lab

Researchers sponsored by the U.S. Army are not designing this small bat-like aircraft to have passengers. Instead, the six-inch-long plane will direct itself, collecting information in urban combat zones and sending signals to soldiers through radio, the University of Michigan News Service said.

Dubbed “the bat,” this small autonomous aircraft would incorporate a navigation system and a tiny low-power radar to get around in the dark. Soldiers could get real-time information from the little robot as it perches on a building, for example.

The Army is joining forces with industry and academia to make the concept for the vehicle a reality. Each of four designated research centers has the mission of developing a different bat-like subsystem of the little robot.

Researchers at the University of Michigan, which received a $10 million Army grant for the project, say they expect to develop an autonomous navigation system 1,000 times smaller and more energy efficient than mechanisms currently in use. This would allow the plane to move by itself, without a third party directing it. They also expect to develop a communication system 10 times smaller than current technologies.

Live bats find their way around by generating sounds and using the echoes from those sounds to determine their distance relative to objects, as well as the size and direction of objects. This navigation system is called echolocation.

The robotic plane will also have auditory sensitivity, using small microphones to gather sound waves from different directions, that will enable sophisticated navigation in the dark. But this bat is not blind – researchers also envision the little aircraft to have stereo vision through small cameras.

The bat may also be able to determine whether there’s nuclear radiation or poisonous gas around, using special sensors.

–Elizabeth Landau, Associate Producer, CNN.com