A Northwoods Almanac for January 22 – February 4, 2010
Wood Frogs on Ice – Sleeping Beauties
Whenever we’re out snowshoeing, I’m always amazed to think that a wood frog (or a spring peeper, chorus frog, or Eastern gray tree frog) might be buried in the leaf litter right beneath the tree we’re passing. Wood frogs in particular have been heavily studied because of their remarkable capability to withstand winters all the way to the Arctic Circle, the only frog to do so.
Two-thirds of their body fluids freeze, their hearts stop, their breathing stops, their brain functions stop. Kept “warm” by the snow and leaf cover, their actual body temperatures drops to between 21° and 30° Fahrenheit during the entire winter.
Except for the fact that come spring, they restart their hearts and then head for the nearest ephemeral pond to breed.
If water froze within our cells, it would expand as it froze, tearing the cellular membranes, bursting blood vessels, and killing us. Actually, we’d never get anywhere near that cold before dying – if our core body temperature drops below 82°, we usually die of hypothermia.
The wood frog freezes selectively. About one-third of its bodily fluids remain liquid, including some water within its cells. They accomplish this by pumping glucose from their livers into their blood as they begin to freeze, raising the glucose concentration in their blood stream to more than 50 times that found in a human diabetic. Ice crystals still form, but now first in its body cavities and around the organs, which then draws some water from the cells inside its organs. This further concentrates the glucose within the cells, creating an antifreeze that can withstand temperatures down to 20°F. The glucose also bind the molecules of water together, preventing the cells outside the organs from dehydrating and shrinking during freezing, so that the cells that do freeze are unharmed.
Using a sugar to prevent freezing isn’t unusual – the antifreeze we use in our vehicles is ethylene glycol, a form of a sugar alcohol similar to glucose.
Like Sleeping Beauty the wood frogs wait for a kiss, but in their case it’s the kiss of the spring thaw. They then also thaw, working from the interior out, the heart thawing first, then the brain, and only at the end, the limbs. Amazingly, the process only takes several hours, and the frogs then hop away none the worse for wear.
Researchers have done MRIs on living frogs, and have been able to observe the entire process of their freezing and thawing, replicating how it happens in nature. They have spent a great deal of time trying to understand this process because of the potential applications to humans. Every day in the United States, twelve people die for want of transplant organs. Every year nearly 50,000 people wait for a heart transplant, but only about 3,000 get one, in large part because doctors have only five or six hours from the time the donor heart is removed until in must be implanted in the recipient. If doctors had 24 hours instead of six by chilling a heart like the wood frog does, many more people could receive transplants.
Another application would be to buy time for people after they experience a severe injury in a car accident or a wartime wound. Without oxygen, our heart cells begin to die in 20 minutes, and our brain cells last just 5 minutes without oxygen.
If a wood frog can stop its heart and its breathing for 8 months while in hibernation in Alaska, and can then restart itself like a car that’s been sitting in a garage, perhaps we can figure out how to do so for just one day and save thousands of lives.
The population of goldfinch at our feeders has steadily increased all winter, and stands now at around 50. While goldfinch nest here in the summer, and many of those nesting birds remain here for the winter, many others migrate. And of those that migrate, many don’t go to one place and settle down for the winter, but rather will move to different locations throughout the winter. So, numbers will fluctuate at your feeders as the winter progresses.
While evening grosbeaks continue to be hard to find this winter, on 1/7, Jim and Tally Schuppel on the Pike Lake Chain had 20 evening grosbeaks come to their feeder, while Jeff Newton near Presque Isle has had a flock about 50 to 60 strong coming to his feeders every day for weeks. He noted, “There are so many that they can empty the feeders about every three days.” About 20 years ago, this used to be the norm for evening grosbeaks. I recall many people, including Mary and I, griping about how much food the evening grosbeaks consumed. On occasion we were known to wish there weren’t quite so many of them! Today, of course, that’s all changed. The evening grosbeak population nationwide has dramatically declined, and it’s uncommon for someone to get a large flock like Jeff is experiencing.
Dave Gammon in Woodruff reports he has had a bobwhite quail coming to his feeder since November. Northern bobwhites, of course, don’t belong here at any time of the year. Most likely, the quail was an escapee from a flock raised by a bird hunter to train his hunting dogs in the fall.
Laurie Timm on Witches Lake has observed a solitary male pine grosbeak coming in to her feeders since December 28th, one of the only reports I’ve received of pine grosbeaks in the area.
Several weeks ago, Jeff Richter from Mercer reported seeing a kingfisher on the Manitowish River near Benson Lake. Kingfishers winter as far north as central Wisconsin, but obviously must have open water in order to catch fish. Though we usually have some open water in the Northwoods every winter, sightings of kingfishers in the area are quite uncommon.
At our feeders in Manitowish, we finally had our first flock of pine siskins appear on 1/16, and a week earlier on 1/9, we had a small flock of bohemian waxwings visit our crabapple trees. We also had a Cooper’s hawk sail by our feeders on 1/10. Since they typically winter only as far north as central Wisconsin, we rarely see a Cooper’s up here.
Jane Wierschem on Blue Lake south of Minocqua sent me a photo of a squirrel who visited their feeders several times this summer. It’s a black squirrel with a bright orange tail, a combo I’ve not seen before. Black squirrels are a color phase of gray squirrels, and relatively common in our area. But a gray squirrel with a red tail is an anomaly. In doing some research on this, I did find one description of gray squirrels that said, “There are rare instances of a reddish colour phase and some animals may also have a combination of colours, for example a black body with a red tail.” So apparently, this combo has been seen elsewhere on occasion. I’d appreciate and e-mail from anyone who has seen this combo before– perhaps this is more common than I am aware.
Groundhog Day or Imbolc
Though we focus our modern day energy on groundhogs on February 2nd, the date actually marks the approximate halfway point between winter solstice and spring equinox, heralding the return of light. This day was known variously in ancient cultures as Imbolc, Oimelc, Candlemas, and the Feast of Brigid.
For pagans, Imbolc was the celebration of the first promise of spring, and the return of the Goddess known as Brigid in Ireland. If the weather was warm at Imbolc, it was interpreted to mean that winter would return.
The Christian feast of Candlemas occurs when candles are blessed for religious use during the coming year. This festival commemorates the ritual purification of Mary forty days after the birth of Jesus. By the middle of the 5th century, candles were lit on this day to symbolize the association of light with Christ.
The ancient Scots looked on Candlemas a bit more meteorlogically. According to Scottish folklore about Candlemas:
“Should Candlemas be fair and clear,
There’ll be twa winters in the year.”
“Twa,” means two, thus, if the weather is sunny and clear, and any animal, including a hibernating groundhog could see its shadow, that bodes another month or more of winter.
This year, February 3rd actually marks the halfway point between winter solstice and spring equinox.
On 1/29, look at dusk for Mars about seven degrees north of the gibbous moon.
The full moon occurs on 1/30. Called the “Wolf” or the “Frost in the Teepee” moon by some Native American tribes, this will be the largest full moon of the year because the moon will be at its closest to the Earth (221,576 miles) of any time during 2010.
Nature, Science, and Spirit
“We find ourselves in a new movement of thought. In a movement where, through science and through the searching of our hearts, everything has become mysterious. Science has led us from knowledge to knowledge, but also from mystery to mystery. Mystery alone can lead us on to true spirituality, to accept and be filled with the mystery of life in our existence.” – Albert Schweitzer