Pug Marks in the Snow and Mind

Winter still grips the Allegheny Mountains. Rain alternates with snow as the days creep toward the official opening of spring. Snowshoe Mountain has accumulated 159” of snow this winter, which is far below the record although we are not yet finished with winter.

Cabin fever feels most febrile when clouds hang low with drizzle, and I wait for bright sunny days with fresh snow to go outside and strap on snowshoes for a hike in the forest and open spaces called ‘balds.’ I spend a couple of happy hours looking at fresh tracks that tell stories about the night-life I rarely see.

There are no tracks of red, gray or fox squirrels because the animals are asleep in leafy dens. Chipmunks are curled up in hollow logs and flying squirrels are nested in my bird boxes. Mother bears stay in their dens for suckling tiny cubs that only weighed a pound at birth, although a juvenile will occasionally wander out to stretch and look for a snack. The day I wrote this log in my nature journal there were no bear tracks.

But there were tiny prints from mice scampering over the snow for a few feet before they dove under. Of all the animals here, I would expect the smallest to hibernate or go into that borderline state of torpor; they must keep their metabolic fires burning to avoid hypothermia. Foxes and bobcats are grateful the rodents are awake, and a hole dug through the snow down to the grass was probably where one pounced on an unseen victim after hearing a murine ultrasonic courtship call. Sex behaviour is often unsafe.

I haven’t seen opossums or rabbits in daylight for months, but their tracks show they were abroad last night. The distance between prints shows they were sauntering across open spaces with a confidence they lack in daytime when they hurry on their way and are ready to dash for cover. One set of rabbit tracks led across an old field where they suddenly vanished, as if the animal had been snatched into the air, but there were no signs of a predator or an Olympic jump. The mystery still dangles.

Our resident striped skunk wasn’t out last night, nor was the coyote pack that patrols the area. As I walked round in a great circle I came upon prints two feet long made by a lumbering biped. Yikes, Bigfoot is here! If only I had brought children along to kid them about the imprint of snowshoes.

The footprints I dream of finding (maybe die to find) look like those of a coyote with four toe pads, but larger and wider and without protruding claws. A panther.

Many local people believe a few still hold out in Appalachia more than a century after they were officially declared extinct. But what is extinction? Is it a complete absence of a species, or the absence of a sustainable breeding population? There have been rare sightings over the years, and a few are hard to deny.

A friend in the DNR was called out one night to a report of a panther feeding on a sheep kill, and he captured it after anaesthetizing the beast with a dart gun. Isolated cases probably escaped from captivity or were deliberately released when they grew too large and wild to be managed. So, it is true that panthers haunt our forests, but mostly stalk our minds. People who live in and around these forests are reluctant to surrender that ultimate symbol of nature’s wildness, and I admit that even the slimmest chance of stumbling on pug marks in the snow brings spice to a walk in the woods.

Next Post: A Costly Thaw

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Shelterbelt Trees in Snow and Fog

Have you noticed how trees hollow out melted sleeves from snow around their boles as our arms would if we could hold them long enough in a snow blanket? And have you wondered why winter fog sinking over open fields is denser than in adjacent woodland? I never gave them much thought until a recent winter walk, but isn’t it often so that the familiar and banal is suddenly thrust to attention to look fresh and strange?

The brain suppresses absorption with too much detail until the detail becomes important or something or someone points it out. I can’t put my finger on what drew my attention to melting snow and thinning fog one day, and it wasn’t more important than the other stimuli bombarding my sense organs. Most noise is filtered out in the conscious brain to avoid being swamped and making us go crazy. But looking intently at something commonplace for the first time can stir uncommon curiosity.

Almost everyone prefers a simple explanation to an obscure one, which is the wisdom of Occam’s razor. When I had students in class they loathed to hear me say: “I have several hypotheses to offer for this observation, and there is evidence for all of them …” That was a way of admitting ignorance without sounding ignorant. Nature is more complicated than we are sometimes wont to admit or accept.

Foggy morning at Jamestown Island

We are drawn to the single explanation, but when we look more closely and are better informed we often find two, and on even closer examination we realize there are four, and then we begin to wonder if we’ll ever get to the bottom of the mystery. We are tempted to turn back to simplicity and turn our backs on provisional knowledge to cling to intuition. I don’t believe in fairy stories, but I know the temptation to be willfully ignorant and it must be resisted.

There is a bottom to the pit of curiosity, a place where facts are finally robust against doubt, but plumbing the depths can take a long time, even generations of science and philosophy. If we boast about our knowledge we fool ourselves because science is still young. Besides, isn’t mystery something to celebrate except when it holds down human welfare or harms our environment (basically the same things)? Mystery is a call to act and understand and is often more intriguing than the mere appearance of knowledge, and perhaps that’s why it is so popular in fiction.

I started musing about snow crystals melting around trees and foggy water droplets vanishing in shelterbelts. Why do they?

Elementary physics offers an easy first answer to my sudden curiosity. Tree bark absorbs some radiant energy, especially the darker shades, even on a cold day when we hardly feel heat of the sun on our faces. It may seem too trivial to change the physical state of water in snow and fog, but the heat stored by day is slowly released to help a slow thaw continue at night. The scientist wants to test a bare theory by experiment. Next time it snows I will check a natural experiment by comparing the melt around maples and oaks with the lighter boles of silver birches, which should in theory remain snow-bound longer.  And here is another question for an inquisitive walker. Does snow melt as quickly on rocks as tree trunks of the same color, and if not why the difference?

A second explanation is that trees offer shelterbelts against chill winds. More heat is lost by radiation from open ground on cold days and freezing nights than among trees, which also reduce wind velocity to stabilize a warmer zone. If you ever get stranded on a bitter night in the countryside it’s wise to find shelter in woods. But it’s hard to see how shelter accounts for melted ‘sleeves’ of snow around trees.

Casting around for other explanations, I wonder how much heat is generated by the thin cylinder of living cells under the bark when trees are looking dead in winter. To be alive is to be engaged in combustion because heat is the by-product of metabolism, generating 500 kJ per mole of oxygen when complete, to be precise.

It seems unlikely the low ebb of metabolism in sleeping winter trees warms the snow, and heat is more likely to be generated on tree bark than under it. To think of microbes and fungi is to remember hot compost and sweaty manure, as well as bubbles of carbon-dioxide popping in the air trap of a home brewer’s dewar. They can be sources of prodigious heat, and commercial breweries sometimes struggle to keep temperatures down.

Tidewater Virginia is marching toward spring and unlikely to see more hard weather so my questions about silver birches and rocks will dangle until I am trudging through snow again next winter.

Next Post: Snow tracks


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Human Egg Farming

We called the ambitious program, ‘Egg Farming,’ over 30 years ago when I worked at Edinburgh University. That goal drew a step closer today as my graduate student from so many years ago published results of growing human eggs in vitro, to a blaze of publicity.

We started by growing mouse and rat eggs in Petri dishes. They were tiny cells nested in follicles that nurse their development, and some reached full size in a week and even ovulated a fertile egg into the culture medium. Our sole competitor in this new science was in the USA where John Eppig developed a more efficient method, and he called the first pup conceived from an egg grown in vitro, ‘Egbert.’ He was a strange and obese animal, and we worried if egg farming was too risky to apply in veterinary or human medicine, but many healthy mice were born later.

Human egg (oocyte). Courtesy: Lucinda Veeck Gosden

It seemed a huge leap from mouse to clinic. Human eggs grow more slowly in the ovary, and we expected the cultures would take weeks or even months and be risky. Progress was agonizingly slow because human ovarian tissue is rarely available for research, especially at the premenopausal ages required. Instead of relying on rodents, we needed intermediate species to forge better methods, and turned to sheep and cow ovaries. Visits to the local slaughterhouse for discarded tissue from butchered carcasses were some of the most unpleasant experiences ever, and almost turned me vegetarian from hearing the crack of the bolt-gun followed by a heavy slump. But they helped us to gain new knowledge when human tissue was unavailable.

A view of Edinburgh and its castle

Professor Telfer’s team in Edinburgh has succeeded with human eggs through careful work with clinical colleagues who asked consent from women to donate tiny slivers of ovarian tissue during C-section. The biopsy doesn’t harm them.

They watched eggs growing in dishes from the earliest stages to full size when a nuclear division occurred and signaled they were ready for fertilization. It is puzzling why the growth is much faster in vitro than in the body, though it is welcome if the eggs are no less competent for making babies. They look normal, but we know from experience how deceptive appearances can be. The only sure test is to fertilize eggs to see if they create healthy embryos, and that will require a special license under UK law.

Why is farming eggs worth the trouble and long struggle?

Progress will continue at a dawdling pace because a mature egg is the rarest cell in the body. For every egg ovulated each month, a man makes 3 billion sperm cells which offer researchers enough material for galloping discoveries in testes. Animals that fertilize eggs outside the body, like frogs and most other species, release as many eggs as they can make because the cost to them is small while superovulation maximizes the chance of making babies. But ovulation in mammals with internal fertilization and pregnancy is restrained by the limited accommodation of the uterus. Nature has arranged a bottle-neck in the egg production line to ensure that few eggs, or only one or at most two in humans, ripen at a time. The rest are consigned to the trash, which egg farming aims to rescue.

If more eggs can be ripened in vitro there will be benefits for animal breeding technology and young patients will have a better chance of preserving their fertility after freezing ovarian tissue during sterilizing treatment for cancer and other diseases. Egg farming will work better for child patients with their larger stores of eggs than in adults. Nearly a quarter-century ago, our first patient at an infant age had ovarian tissue stored while she was treated for Wilm’s tumor. The news from Edinburgh today was welcome for her and others with investments in the frozen ovary bank.

Next Post: Snowy tracks

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From Faith to Hope in 2018

I don’t have much faith in my New Year Resolutions, but there is a four-letter word I will try to keep muttering as world news unfolds in 2018. No, I don’t mean that word!

When Galadriel expressed the state of world affairs in an elvish way, I think it was a good summary of general feelings today. “The world is changed. I feel it in the water. I feel it in the earth. I smell it in the air. Much that once was, is lost … ” (from The Fellowship of the Ring).

Devonshire tree sustained for centuries

The New Year is supposed to be a time of cheerful anticipation of good things ahead, but there is a widespread mood of pessimism and foreboding after several decades of relatively stable world order, even talk of apocalypse by the end of the century. People who lived through the 1340s and 1940s might understand because they feared the world they knew was coming to an end. The modern challenges are not, or at least not yet, the pandemic disease and political tyranny they faced, but we hear questions whether liberal democracy and other fond institutions can survive the threats of climate change and food insecurity, ecology and extinction, mass migration and nuclear arms. The booming stock market cannot be a salve for an Anxious Age struggling to balance sustainable living with social justice.

Faith is a trust in promises made. We grew up with expectations that lives will continue to prosper in almost every way, and should look back gratefully on more optimistic times. But I wonder if ‘faith’ should now be replaced with the more tentative word, ‘hope,’ which has a more fragile meaning. Hope is a brave outreach for something good that is presently unseen, maybe unknowable, but seems irrational and even foolish to cling to. But I find encouragement in those four letters from stories in history and wisdom literature, like the ones started with the Oriental prince who left the court to become the ‘enlightened one,’ the baby abandoned in the rushes, the other baby born in a manger, and a hobbit who left an obscure shire for a long journey. Those are stories that teach us something can come from nothing, and hope is the comforting watchword that it will be future good. I wish that for myself and for all at this season.

Next Post: Heat in the Dead Woods

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A Biologist in Paradise – new book

I raced to finish this book of 40 essays and memoirs before Christmas. A BIOLOGIST IN PARADISE is as much literary as scientific. It is not a science books for scientists, nor a nature book for naturalists, but I hope both parties will read it.

It is FREE to download until Sunday December 17, 2017, when Amazon forces it back to $2.99, the lowest price allowed for a book of this size (80,000 words). Click the link to the Amazon page or type my name in Amazon Books for countries outside North America.


Profit from books I publish at Jamestowne Bookworks goes to a local literacy charity. A print book will follow. After so much effort I hope for more readers but it is hard for authors to get much attention when so many books are published. The greatest thing a satisfied reader can do for an author is to spread the word by writing a review on the Amazon page (a line and appropriate star rating will do), and/ or recommending the book to friends and spread on your social media.


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