Decay fungi are generally disdained, but wood is held in high regard. The meeting of both can create emotional conflict and challenges the viewer to reevaluate their position on functional wood and natural ornamentation processes. – Dr. Sara C. Robinson

Gene handed me a small block of maple, maybe an inch across. “This is spalted wood,” he told me. “Do you see the fungus?”

Among other things, Gene is a woodworker. We had run into each other at the coffee booth at the farmer’s market a couple of times and had got to talking about my blog. That led to a conversation about fungus, during which he asked me if I knew about “spalted wood”, a fungus-infected wood much prized among woodworkers. I hadn’t, so he had brought me a piece.

I examined the block. It was cut into a cube and sanded smooth on all sides – the leftover end cut from a pen blank Gene told me. The color was creamy beige, the way you’d expect maple to look, but on its surface it appeared as though someone had taken a fine-point black pen and had hand-drawn tiny wiggly intersecting trails all over the block.

• “Yes, right here,” I told him, pointing to the lines.
• “No.”
• “What?”
• “That’s not the fungus.”

Gene went on to explain that the fungus itself – the main portion of it – would have been located within the spaces when it was alive. The lines —called zone lines – merely showed where one fungus had encountered another. Yes, the lines were technically part of the fungus, but in effect were really just boundaries demarcating each fungus’s territory.

In essence, these were the lines in the sand between warring fungi.

Armillaria / Honey Fungus (Robert L. Anderson, USDA)

The Forest Eaters

No fungus illustrates this warfare better than Armillaria, a genus of parasitic fungi that thrives on living, weak or dead wood.  Armillaria is commonly known as Honey Fungus for its honey-colored mushrooms that form around the base of dead or dying trees.  Many species of Armillaria are destructive root-rot pathogens, invading and killing a wide range of host trees including forest and cultivated hardwoods, conifers, orchard trees, and other woody plants like coffee trees and rhododendrons.

Armillaria’s invasion begins in an old log or, commonly, in a cut tree stump. Once firmly established it takes on a military-like operation to expand its range. With the stump acting as home-base and supply depot, the fungus creeps its way along the stump’s roots and expands to nearby trees by way of root-to-root contact. As long as the roots of other trees are touching or in close proximity, the Armillaria hyphae (microscopic thread-like filamentous growths) can continue to spread. As it spreads, the hyphae forms masses called mycelium – a web-like collection of filament.

Rhizomorphs give Armillaria its other popular name: Shoestring fungus. (Joseph O'Brien, USDA)

At the same time other Armillaria hyphae are mounting a cross-country expedition, hunting a new host across treacherous open ground. The hyphae expand in every direction, growing through the soil and under the leaf litter. The distance the mycelium can spread is limited, however, because, until it reaches a new food source, it must rely on the home stump. And it’s dangerous crossing open ground. The hyphae stand a high chance of being damaged by animals, fire, or even too much direct sunlight. A damaged section could leave patches of mycelium cut off from the supply chain.

So for the cross-country trek, the fungus steps up its defenses. More filaments are laid down and from these rhizomorphs are formed.  Also known as mycelial cords, rhizomorphs are strong root-like structures formed of bundles of parallel-running hyphae protected by a hard outer shell of melanin.

Rhizomorphs are remarkable in that they function as a unit, much like a single root or vine with a growing stem-tip. They are strong enough to invade healthy wood and can grow quickly — up to 19 mm per day in some species – even without having access to a new host. Like vines and roots, they branch regularly, but unlike their plant-counterparts, rhizomorphs branches may rejoin each other or join different branches through a process called anastomosis. This gives the entire network strength that is greater than the sum of its parts. If a rhizomorph is severed, it may still be connected to the rest of the colony by way of other attachments.

These features make Armillaria extremely robust. Unchecked, a single colony of Armillaria can cover acres of land and live for centuries. In fact, one specimen of Armillaria solidipes in Oregon is considered to be the largest living thing in the world, estimated to cover over 2,200 acres (890 hectares) and be at least 2,400 years old. Over that time, this colony has killed tens of thousands of trees in the Malheur National Forest [pdf] and surrounding areas.

Three disease centers in a virgin, mixed conifer forest in western Montana. The lowermost center covers nearly 20 acres (USDA /FS)

And there is no way to stop it.

Once the rhizome reaches a new host, it sends word back to the home base via chemical signals. The home colony responds by committing all of its energy and resources to that section and the rhizomes begin to infiltrate the wood.  The mycelia are responsible for drawing water and carbohydrates from the tree to feed the fungus. To do this the hyphae first break down the wood by secreting enzymes into it. Once the nutrients are broken into simpler forms, they are absorbed by the mycelia.

The process usually begins below ground, travelling upward along the roots. In trees, fan-shaped mycelial mats spread beneath the bark and up the tree, sometimes to a height of several feet.

On dead and decaying wood mycelial mats may glow in the dark. (Fabio Stergulc, Università di Udine, Italy)

The fungus spreads through the wood claiming more and more ground. This is the place where the battle lines are drawn.  Where no other fungus is present, Armillaria spreads unfettered. However, if it encounters another fungus it creates dark tangled walls of mycelia –zone lines — to protect itself and its resources. Because the fungus is within the wood, not just on the surface, zone lines enclose 3-dimensional spaces.

Interestingly, it used to be thought that fungus populations of the same species worked together (the “unit mycelium”) within the same wood, fusing, cooperating and sharing their nuclei.  But, through DNA testing, mycologists at Exeter University determined that Basidiomycetes fungi (which include Armillaria) recognize different genetic lines of their own species as an enemy. This intraspecific antagonism means that every colony of Armillaria retains its own unique genetic identity.  It was by testing for this unique genetic identity, that mycologists learned that the Armillaria solidipes infecting Malheur National Forest was a single colony.

The intraspecific antagonism also means that when two genetically distinct colonies of Armillaria meet, they both erect their own zone-lines, creating a thick double wall.  And this brings us back to spalted wood.

Painters of Wood

 At the age of seventy-three, I’m getting old and stiff, but turning is for me being young again as each stiff, old, distressed piece of wood comes alive with a refreshing new chance at life. – Melvin Lindquist, Artist Statement for the Smithsonian (1984)

Spalted Florida Hackberry Hopi Bowl (by Melvin Lindquist)

Spalting is defined as any coloring on wood that is caused by a fungus infection. Besides zone-line formation, there are two other kinds of spalting — pigmentation and bleaching.  Pigmentation is the addition of color to the wood. Bleaching is just that, a whitening of the wood.  Armillaria causes both bleaching and zone lines, which makes it nice for creating spalted specimens.

Working with spalted wood was all but unknown until the 1970’s. In fact, fungus-infected wood was studiously avoided until then. It’s tricky stuff to work with since the fungus is actively rotting the wood, and multiple fungi can rot a single piece of wood at different rates. This can create weak areas in the wood. As such, spalted wood was considered inferior.

However, in the 1950’s, a woodturner in the Adirondacks of New York was experimenting with spalted wood. Melvin Lindquist, today a foundational legend in the woodturning community, is credited with inventing several new machines and developing pioneering techniques for turning wood. He was also bold enough to confront the problems of spalted wood head on, and the pieces he was turning out were stunning.

But it wasn’t until the 1970’s, that his son, Mark, an acclaimed wood sculptor in his own right, brought his father’s work to light through a series of regular essays in woodworking magazines. At that point, to quote Fine Woodworking magazine, “…Melvin and Mark Lindquist unleashed spalted wood upon the world.”

Today woodworkers have fully embraced spalted wood. The colors and lines add richness to otherwise straightforward wood grain. Spalting now appears everywhere that worked wood is found: sculptures, food vessels, gun-stocks, furniture, jewelry, knife-handles, lamp bases, picture frames, writing implements, and even musical instruments.

In the old days, woodworkers scoured the forests, picking up downed logs and cutting them open, hoping to find a beautifully spalted piece of wood. Sometimes they would leave pieces of wood outdoors, in hopes of it picking up a spalt-inducing fungal infection. But this was chancy work. Lots of logs had to be cut open before a suitable specimen would be found. Mostly they just found rot.

Nowadays woodworkers try to induce and control spalting on their own. To develop usable spalted wood requires a delicate balance. Too much fungus working too fast, and the wood decays, leaving it useless. Too little fungus or the wrong pairing of wood and fungus, and spalting doesn’t occur. Too slow and nobody wants to wait for it. Not only that, but many spalting fungi (like Armillaria) require a fungus to go before them in order to spalt. It’s a tricky balance. So the goal of intentional spalting is to find ways to induce spalting quickly, reliably and with predictable results without undue damage to the wood.

Probably nobody is more the expert on doing that than Dr. Sara C. Robinson, Research Assistant Professor at Michigan Technological University. Also a talented woodworker, Dr. Robinson (to use her words) blurs the line between art and science. Armed with a PhD in Forest Science and an eye for beauty and artistry, she has made it her quest to turn spalting from an accidental find into a predictable science.

Through her work at Michigan Tech and at her lab at the University of Toronto where she is also an Assistant Professor, Robinson has published a raft of papers on the science behind spalted wood – how to stimulate spalting, ways to create specific colors, and wood preferences of various species of fungus, among other things.

But all of that research means nothing if the information doesn’t get into the hands of the artists. So Robinson

"Sunset" An aspen bowl with blue, pink, and purple stain spalting (by Sara C. Robinson)

makes it a point to do just that. Not only does she apply what she learns to her own beautiful pieces, but she freely and passionately shares the results of her research with woodworkers and artists.

She has blogged on spalting for Fine Woodworking under the pseudonym “Dr. Spalting,” where she amicably provides woodworkers with the results of her latest research – such things as lessons on various fungus species and her take on alleged spalt-enhancing tricks of the trade (urine?).  As well, Robinson is an entertaining speaker and workshop presenter. In fact, it was Gene, the woodworker from the farmer’s market, who gave me her name after attending one of her workshops.

So, true to their invasive nature, decay fungi have extended their reach.  Once confined to forests and old wood piles, they have crept their way into the laboratory where they are nurtured like favored pets. In petri dishes and test boxes they are offered the food and substrate they like best, given the right mix of light and water, and are rewarded for good spalting performance.

At the same time, in a stretch that seems to defy our natural aversion to decay, the fungi and the marks they leave have made their way into fine art.  In the hands of artists, those swashes of color and delicate trails are no longer portents of imminent decay, but instead are pearls to be sought in an oyster of wood – some found by lucky accident, others cultured by design.

I admit, I’m now a fan of spalted wood.  In fact, as I was finishing up this post, I decide to take a look at all my wood products at home to see if I had accidentally bought any spalted pieces over the years. I checked all my furniture, wooden bowls, sculptures, and knife-handles. Alas, aside from the little sample Gene gave me, my house is spalt-free. This is a deficit I plan to remedy. I’ll let you know when I find the right piece.

Rayner, A., & Todd, N. (1977). Intraspecific Antagonism in Natural Populations of Wood-decaying Basidiomycetes Microbiology, 103 (1), 85-90 DOI: 10.1099/00221287-103-1-85

Worrall, J. (2004). Armillaria root disease The Plant Health Instructor DOI: 10.1094/PHI-I-2004-0706-01

Aequorea victoria, a bioluminescent jellyfish (Wikipedia)

I remember, as a teen, working at a summer camp on a brackish river near the Chesapeake Bay. One night a bunch of us were sitting on the dock and I noticed small flashing blueish white lights in the water. At first I thought they were tricks of light, but on close inspection (fishing one out with someone’s hat) we found they were small jellyfish, tiny enough to fit in a tablespoon. I don’t know what kind they were, but floating along in the dark water, they seemed of another world.

That was my first exposure to bioluminescence (the emission of light from living things), beyond fireflies.

If you ask a group of children if they know any animals or plants that glow in the dark, the answer usually includes fireflies and “those fish that live really deep in the ocean.”

But the world of bioluminescence  is much broader than that. So today I am going to give you some sciency info about bioluminescence. Maybe these will give you some ideas on how to add a creepy glow to an otherwise pitch black forest or give a spark of brightness and magic to a character.

How it works

Making light: From UCSB

Bioluminescence is the reverse of photosynthesis. In photosynthesis, a living organism captures light and carbon-dioxide (CO2) to make organic materials. The byproduct is oxygen. In bioluminescence, oxygen is used to break apart organic material. The byproducts are CO2 and light.

A few animals (the angler fish for one) use bioluminescent bacteria to emit light for them. But most producers of bioluminescence create their own light. These produce two chemicals: luciferin (a pigment) and luciferase (an enzyme). The luciferin reacts with oxygen to create light. The luciferase acts as a catalyst to speed up the reaction.

The reasons for bioluminescence are as varied as the number of organisms that exhibit it. Adult male fireflies use it to attract mates. Firefly larvae may use it to warn off predators. Anglerfish use it to attract prey. Other creatures use it as camouflage, to ward of predators, as communication, or even as a sort of a flashlight, to help the animal see.

A Glowing Sea

Near seven o’clock in the evening, the Nautilus lay half submerged, navigating in the midst of milky white waves. As far as the eye could see, the ocean seemed lactified.—Jules Verne, 20,000 Leagues Under the Sea

The milky sea in a satellite image (Steven Miller / NRL)

Bioluminescence is rare on land, but in the sea it is the rule, rather than the exception. Edith Widder, an expert on the topic, says that 80-90% of the creatures she brings up from the deep ocean exhibit bioluminescence. In the dark depth of the ocean, it is the only light that marine creatures ever see. Luminescent displays by sea life include individual flashes of light, repeated flashes of light, and animals squirting luminescence into the water.

In some deep ocean areas, scientist have observed glowing orbs of liquid light the size of footballs made by hundreds of tiny animals squiring luminescence into the water.

Many of the organisms that exhibit bioluminescence are very small but occur in large numbers so their light affects huge swaths of the sea. As a rule, they glow only upon disruption – when waves crash, ships churn the water, or when fast-moving fish or sea mammals swim through them.  The well-known Red Tide in California is caused by tiny dinoflagellates that light up in response to the waves crashing on the shore.

Bioluminescent bacteria occur in almost all oceans. In the Indian Ocean, they cause the spectacular “milky sea” phenomenon where sailors report sailing through sea that glows from horizon to horizon with a soft milky white light.

Surfing in a sea of light:

Foxfire

Panellus stipticus, a source of Foxfire

Tom said we got to have SOME light to see how to dig by, and a lantern makes too much, and might get us into trouble; what we must have was a lot of them rotten chunks that’s called fox-fire, and just makes a soft kind of a glow when you lay them in a dark place. – Mark Twain, “The Adventures of Huckleberry Finn”

Now you might not think that glowing fungus would add much to a scene, but imagine this: a spooky dark forest where suddenly glowing green orbs hover 6 feet off the ground or a whispy white light seems to leak out from behind a tree’s bark. Woooo….. cue the spooky music.

Armillaria at night ( Flickr: Bruce McAdam (CC))

Some fungus, such as Panellus stipticus, bears mushrooms that glow green.  These bioluminescent fungi (along with dozens of other species) are also known as Foxfire, “Fairy Fire,” or “glow wood”. Foxfire has made an appearance in writings from Aristotle to Mark Twain and has even been referenced on the TV show Lassie.

Armillaria fungus acts in a different way to provide glowing white light.  It is a fungus that infects trees from the base up, forming mats of threadlike fibers beneath the lower bark. Once the tree starts to die, the Armillaria begins to glow from behind the bark. As the tree rots, the bark peels and falls away, exposing more of the Armillaria and thus, more of the white light. Some mysterious sightings have been attributed to the glow of Armillaria – including Beowulf’s “fire on the water.”

Fireflies – Gentlemen start your flashing

Yes, you already know about fireflies. But here’s a thing that’s really interesting that a lot of people don’t know – in some species, all the fireflies in a single population synchronize their blinking. In fact, the synchronized fireflies of Elkmont Nature Reserve in Tennessee put on such a light show that thousands of visitors flock there every June to witness the display firsthand.

Check out this video:

[Edit Friday evening ] I just came across this! Stunning Long Exposure Photographs of Gold Fireflies in Japan

More

Top 10 Light Emitting Creatures

The Bioluminescence Webpage by University of California, Santa Barabara – Quite possibly the most comprehensive site on the web for bioluminescence

TED TALK: Glowing Life in an Underwater World, in which Edith Widder explains (among other things) how there is so much bioluminescence in the ocean, that the seawater in toilets on her ship glows in the dark.

So was I once myself a swinger of birches;  And so I dream of going back to be. – Robert Frost

Stand of Birches in Northern Ontario ((CC) Douglas Stebila)

Pity the tree, a novelist’s throwaway reference, relegated to the margins of an otherwise colorful scene, referred to merely as, “the tree.”  If not that, then described with an over-used cliché – “stately elm,” “mighty oak,” “whispering pines” …

Of course, unless you are a Lorax, the tree is not your main character, so who cares? But in the way that writers are urged to add specifics to their descriptions (name brands, breeds of dogs) a properly defined and well-described tree can add richness and a measure of reality to a setting.

So this week:  Five things fiction writers need to know about trees —

1. Kinds of Trees

The word “spruce” entered the English language from Old French Pruce, the name of Prussia. Spruce was a generic term for commodities brought to England by Hanseatic merchants and the tree was believed to have come from Prussia. (Wikipedia: Spruce)

There are 100,000 species of trees. This means it should be easy to go beyond oak, maple, or pine for your story. Each one of these has different characteristics, regions where it thrives, and place it grows best.

For instance, birches grow in stands of same-aged trees that have taken over open areas. They are one of the first trees to colonize areas that have been scorched by fire or heavily logged.  Cottonwood trees grow along streams and rivers in order to survive prairie fires. The tree gets its name from the fluffy white seeds that blow all over. These settle in the water and some wash ashore and take hold as new trees.

In addition, some trees can add interesting color, links to history and mythology and metaphor to a story –none of which a writer will ever get from the word “tree”  –

Did you know that when Achilles kills Eetion during the Trojan War, the Mountain Nymphs planted elms on his tomb?

And in 1971, Apollo XIV astronaut Stuart “Smoky” Roosa, a former smoke jumper for the US Forest Service, carried the seeds of several species of tree, including the American Sycamore, to the moon to honor the USFS. Today the trees planted from those seeds, known as the Moon Trees, thrive in cities across the US.

Several species of truffles have symbiotic relationships with oak trees.

The Biscarrosse Elm 1350-2010

2. Lifespan

Trees have a specific lifespan.  If your story has soldiers camping in a 100 year old stand of birches, you would be mistaken. Birches only live 30-40 years.

On the other hand, The Biscarrosse Elm, a field elm (Ulmus minor), reputedly planted in 1350, died of Dutch Elm disease in 2010.

Legend has it that girls deemed promiscuous were forced to stand naked upon a barrel beneath the tree for a day. One unfortunate, unjustly accused, died of shame, the tree annually producing a corona of blanched leaves in her memory. (Wikipedia)

Once you know what kind of tree you are writing about, you can look up how long it might live. Here are some handy charts:

• Lifespan of common Canadian trees in urban settings.
• Lifespan of Virginia Trees
• List of Oldest Trees

3. Size as a function of age

How old is this tree? (Virginia Tech)

Each species of tree is genetically determined to grow to a specific size at a predictable growth rate. Therefore, a writer can’t just toss out sentences like, “The 50 year old maple was so huge, that the three children couldn’t get their arms around it.”  That may not be true for maples.

A shagbark hickory with a 10 inch diameter and competing with other forest-grown trees can easily be 75 years old while a neighboring red oak with the same diameter would only be approximately 40 years old. (About.com)

So how do you figure out a tree’s age as it relates to size?  

There is a formula for that!  :  Diameter (inches) x growth factor = tree age (years)

1. Determine the kind of tree
2. Determine tree diameter in inches measured at 54 inches (chest high) above ground. (Diameter = circumference divided by 3.14)
3. Find the Growth Factor for your species of tree using this table for common North American trees.
4. Do the math

(Then cross check that with average lifespans for that species.)

For the fiction writer, this formula probably works better in reverse. Imagine a story where the grandfather planted a red oak tree 50 years ago. How big around would the trunk be today?

Age / Growth factor = diameter (inches)  –>   Diameter x 3.14 = circumference
50 years / 4.0  = 12.5 inches diameter   = 39.25” around

'Honeycrisp' TM apple tree

4.  Apple Trees

Apple trees do not work the way many people think.

Yes, you can plant an apple seed and, after some years, you will end up with an apple tree and fruit. But here’s the thing:  Due to a trick of genetics you will not end up with the same kind of apple you planted. In fact, you will end up with a never-before grown kind of apple that may or may not taste very good.

When you see an endless orchard of Golden Delicious apples, these were not grown from Golden Delicious seeds.  Every tree in that orchard came from a shoot (or “scion”) from an existing Golden Delicious tree that was grafted onto rootstock.

Today, if you buy an apple tree, it consists of both parts – the scion, which determines the type of fruit you get, and the rootstock which determines the maximum size of the tree (and thus, years to fruit production). The rootstock may also provide some resistance to specific pests or environmental stressors.

The choice of root stock allows orchard owners to select the stock that best suits their environment while still producing the type of apple they want.

Then where do new kinds of apple come from?

Since every apple seed planted creates a new kind of apple, experimental cultivators plant many seeds hoping that one will result in the next consumer favorite. University of Minnesota’s Horticulture Experiment Station, cultivator of the immensely popular Honeycrisp (TM)* apple, is one such place.

*Names of new apples are trademarked by their cultivators. 

Oaks with Canker

5. Some really great tree words you might enjoy using —

Xylem and Phloem (the little tubes that get water & nutrients to all parts of a tree)

Conifer (trees with cones)

Catkin (those fuzzy caterpillar-like flowers on trees; from the Dutch word for kitten)

Punk or punky wood (fallen wood that has started rotting but hasn’t turned soft; great for fire-starting)

Pippin (one of several words used to describe an apple that came from a tree grown from a seed)

Samara (the little “helicopter” things that fall from Maples and other trees; actually a fruit!)

Canker and Anthracnose (general terms for tree diseases that result in “sores” or those bulgy lumps and bumps on trees that inevitably morph into faces when you’re lost in the woods.)

Widowmaker (term used by loggers to describe a high branch that is broken or dangling and may fall and kill someone at any moment)

Gall (outgrowths on trees, sometimes caused by insects, disease, or fungi; some galls are used to make ink or ointments.)

And now, in case your main character is lost in the woods and needs to make a fire, here is how to start a fire with punk wood

..this heart within me burns.”
– Samuel Taylor Coleridge, Rime of the Ancient Mariner

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Welcome to Friday Fiction Facts: sciency things that fiction writers need to know.

This week the focus is on horses – not a lesson for the experienced horse-writer (or rider), but for those of you whose horse-related experience consists of a pony ride at the fair, reading The Black Stallion, and watching The Horse Whisperer.

Rather than have you write something that will have all your horse-savvy readers rolling their eyes, I thought I’d arm you with some basic horse facts.  For the purposes of this post, I am assuming the horses are only a minor part of your story so am providing you with just enough that you sound like you know what you’re talking about.

So here we go .. six things fiction writers need to  know about horses.

1. English or Western?

Which style of riding your characters are going to do? Your choice will determine the kind of horse you pick, the terminology you use, and what your characters do with those horses.

A Thoroughbred jumping on a cross country course (CC)

English: This is the stuff of show jumping, girls at boarding school, hard hats and jodhpurs, and dressage.

But that’s not to say that nobody rides English just for fun. I rode English and showing was only a small part of my riding. Most was trail riding and just messing around with friends.  And, except for showing, we wore jeans, not jodhpurs.

Western: This is “cowboy” riding – rounding up cattle, rodeos, dude ranches, rugged trail riding, and competitions that show off skills like barrel racing and calf-roping.

2. Breeds of horses

Just like in dogs, there are breeds of horses and each has a purpose.  By that same token, most of the horses that kids and regular people have are not purebred. They are just horses.

However, if your horse has a specific job – rounding up cattle or carrying a girl over jumps at a horse show – it will probably be of a specific breed.  There are a zillion breeds, but here is a basic set you can use in pretty much any circumstance:

An Arabian: Quite possibly the prettiest little horse out there. (CC)

Thoroughbred:  Notice, this is a breed, not an indicator that a horse is a “purebred.”  Thoroughbreds are the racehorses you see at the Kentucky Derby. They are long-legged, fast, spirited, and often skittery.  They make good show jumpers and cross-country racers but can be a bit of a handful. Not for the inexperienced rider.

Quarter Horse: This is your good solid dependable cow horse.  You see Quarter Horses working in rodeos, on cattle ranches, and carrying kids to first place in both English and Western horse shows.  They are sprinters, racing on quarter-mile tracks. Considered “bomb-proof”, you also find Quarter Horses under city-folks at dude ranches.

Arab (or Arabian) and Morgan:  These are both great little all-around horses.  They are extraordinarily pretty, versatile (both English and Western), slight in stature, spirited and flashy, but not too much to handle for a good rider. The horse that played the Black Stallion in the 1979 movie was an Arabian.

Clydesdale, Percheron, and Belgian: These are draft horses, used to pull plows, heavy wagons, and Budweiser. The wide-rumped grey circus horses with the girls on top are Percherons.

3.  Colic

A cowboy on a Quarter Horse (Photo: Xan Gerson)

Colic is a common horse ailment that can add a helpful twist to your plot. Yes, it’s just like the colic babies get, only bigger and more dangerous.

Horse can’t vomit, so if they get the wrong food in their system, they can build up painful gas in their gut.  Sometimes it’s so bad, that the horse wants to roll on the ground to relieve the pain. This is dangerous because violent rolling can cause an intestinal torsion.

The first-line treatment for colic is to walk the horse to prevent it from lying down. This has to be done until all the gas works its way through the horse’s system, a process that can take hours.  This presents an excellent excuse for your teenage main character to spend the night at the stable with all her friends so they can take turns walking the horse – among other things. (Not that I’d know anything about that …)

Blacks and Chestnuts and Bays, oh my!

4. Lingo

Like any other field, the world of horses has its own collection of jargon. If you don’t want to sound like you just stepped off the city bus, then you’ll want to get the words right.  Here are some links to help you out –

Colors & markings  (No “brown” horses please)

Ages and sexes (Ain’t she a cute little filly)

Pro Tip:  Race horses turn 1 on the first January 1^st after they are born, so breeders aim for January foals.

Gaits  (The basic 4: walk, trot, canter, gallop)

Pro Tip: Use “gallop” sparingly.  Despite what movies would have you believe, most traveling on horseback is not done at a gallop.  Walking and cantering (or loping if Western) are the two most-used gaits.  Reserve galloping for races and runaway wagons.

Tack aka Equipment (It’s “reins” not “reigns”)

Vocalizations  (Just say nay to “neigh”)

Pro Tip: Horses are introverts. All that whinnying and carrying on you hear in movies? It doesn’t happen.  Also, they do not snort at you like a bull.

Przewalski's Horse (CC)

4. A word on stallions: Leave them out.

Resist the temptation to have your character ride around on a stallion.  Stallions are adult male horses that have not been castrated. These animals are not part of everyday horse riding. They are filled with testosterone and dominance issues.   They are dangerous, challenging to manage, unsuitable for children and novices, and are unwelcome in many boarding stables and farms.

If you want your horse to be male, make him a gelding (castrated male).

5. Wild horses can’t drag you away

With one exception, there is no such thing as a wild horse.  Those Mustangs galloping across the western plains of the US are “feral horses,” descendants of domestic animals. Same with the Chincoteague ponies.

The only true wild horse is the Przewalski’s horse, native to the steppes of China and Mongolia. The Przewalski’s horse was rescued from near extinction in the early 1900’s and today all Przewalski’s horses are all descended from 9 animals that remained in 1945.

6. The measure of a mare (or any horse)

“Wow. He’s a big horse! How tall is he?” 

“He’s sixteen-two.”

What?

Horses are measured in “hands.” A hand is 4 inches and the measure is from the ground to the horse’s withers (shoulder).  Hands are expressed in full hands plus any inches, thus a horse that is fifteen hands and two inches is said to be “fifteen-two” which is written 15.2 hh (hands high).

“Noddy”, the tallest horse in the world at 20.2 hands

Sizes –

Pony:  An adult equine that is under 14.2.
To be clear, a pony is not a baby horse. It is a smaller animal.

Small Horse: 14.2-15 hh (Arabs, Morgans)

Average horse:  15-16.2 hh (Quarter horses, Thoroughbreds)

Tall horse:  16.2 – 18.2 hh (Draft horses)

So now go ahead and add that short horse scene you were thinking about.  Let grandpa introduce Josh to his old chestnut quarter horse that used to be the envy of ranchers for miles around.  Let Caitlin go to a horse show to watch her new friend put a sassy little grey Arab mare over a set of stadium jumps.  Or just have your hero ride off into the sunset. Happy trails!

Your main character is trapped! She’s in a 10x10x10 foot room buried deep beneath the ground. Or maybe she’s tied up in an old walk-in freezer, the door sealed tight. Or perhaps your hero and sidekick are in a space capsule or an undersea rover; all systems have failed! Quick, how long do they have before they run out of oxygen?

Here are five things fiction writers need to know about The Airtight Room.

1. It’s not the Oxygen, it’s the CO2

The issue of suffocating in an enclosed space is not one of running out of oxygen; it’s one of being poisoned by carbon dioxide — CO2.  CO2 becomes mildly toxic at a concentration of 1%. (Normal atmospheric concentration is 0.036 %) A concentration of 10% can cause respiratory paralysis and death within minutes.

2. The more you breathe, the worse it gets

How fast the CO2 level builds depends on how fast you produce it. This would be related to how fast you are breathing. At rest you would exhale much less than if you were exercising.  A moderately active or stressed person produces about 1.7 cubic feet of CO2 per hour.

3. How long? There’s an equation for this!

Assuming a concentration of 3% CO2 is the highest safe limit, you can calculate how long a given number of people can stay in a given sized space before toxic levels of CO2 build up —

T = Number of hours before CO2 reaches toxic levels and your character(s) could die.

  (Volume of air inside the room in cu ft) x (3% or 0.03)

T = ---------------------------------------------------------

  (Number of people) x (one person's hourly production of CO2 in cu ft)

So, let’s see how that works for one person in a 10x10x10 (1000 cubic foot) space.

     (1000) x (.03)        30

T=   ------------     =   ----   = 17.64 HOURS

     (1) X (1.7)          1.7

4. Your main character will feel the pain

But, while your character may have 17 hours to get out of that room, keep in mind, she is not going to be much help when it comes to figuring out how to escape. The effects of CO2 buildup are going to take their toll fairly quickly so, unless it happens right at the beginning, there will be no clever MacGyver inventions or elaborate escape plans being hatched. Rescue is going to have to come from the outside.

Hour by hour (based on 1 person in a 1000 cu ft room), here is what your character is going to feel over time:

Note that times are rounded and very generous. In reality, the adverse effects will be compounded.  In other words, at 24 hours, your character has already been exposed to increasingly high CO2 levels for a full day. Also, his or her rapid breathing will have created CO2 faster that 1.7 cu ft/hr that we used for the calculation.  This is why rescue will need to take place well before 18 hours.

5. It’s not over when it’s over

Recovery is not immediate. Your newly rescued main character will not be running away from bad guys, fighting off killer zombies, or swimming 200 meters back to the boat.  Exposure to 2% CO2 concentrations for hours can result in loss of energy, headaches, and feeling of being run-down that can take days to go away.  Exposure to 4% or higher can damage the body and cause long-term or even permanent side effects.

So, my advice is to get your main character out of that room well before CO2 levels become dangerous. Otherwise, he or she may not be around for your sequel.

Got a question or an idea for Friday Fiction Facts? Let me know.

*Disclosure:  This post is based (and partially copied) from an answer to a query I wrote on Google Answers in 2003.  The work is my own.

From Alister Hardy (1960)

Last week the popular website IO9 ran a tongue-in-cheek story headlined, “Could Humans Have Evolved From Dolphins?”  While posted in fun, originally the humor wasn’t entirely clear (it has since been updated), so the story caught ire of some of the scientific blogging community.

This was not because the story was so outlandish. It was because it seemed to give credence to a pseudo-scientific theory that should have been put to bed decades ago—that is that our species separated from our primate cousins due to our affinity for and eventual habitation of an aquatic environment.

In other words, we were once water apes.

So where did this idea come from? And more importantly, why is it still around?

The idea of a human water origin goes back to 6^th century Greeks and has been revived in several forms since. In recent modern times the proposition that humans may have spent some time as sea mammals, was first brought to light in popular press by zoologist Desmond Morris in his 1967 best seller, The Naked Ape: A Zoologist’s Study of the Human Animal. There, in his unabashed exploration of the human animal as a zoological curiosity, Morris suggests that there is one “ingenious theory” that could explain our lack of body hair, streamline bodies, upright posture, and several other anatomical anomalies that separate humans from all of our primate relatives.

“The graceful shape of Man—or Woman!—is most striking when compared with the clumsy form of the ape." - Alister Hardy (photo: NASA)

That “ingenious theory”, now referred to as the Aquatic Ape Hypothesis (AAH) or Aquatic Ape Theory (AAT), was first considered by Antarctic Marine Biologist Sir Alister Hardy. Hardy proposed that there was a time in human evolution when we were aquatic apes—creatures of the sea.  Hardy was aware that his proposition was far from the mainstream – so far in fact, that he sat on it for almost thirty years.

Finally, however, he broke his self-imposed silence and tentatively presented his thoughts at a conference of the British Sub-Aqua Club in Brighton, England in March of 1960. The swift publicity surrounding his speech surprised Hardy, but the popular press’s “abbreviated” treatment of the topic worried him.  Fearing he was being misunderstood and eager to clarify his views, Hardy gladly accepted an invitation from New Scientist magazine to present his theory in full.  On March 17, 1960 his article, Was Man More Aquatic in the Past? was published.

In that article, Hardy paints a picture of our primate ancestors being forced out of the trees and onto the sea coast by stronger competitors and predators. He supposes that at first we ventured into the shallows crouched on all fours digging for shellfish and other easily-gathered prey. Eventually we may have stood upright for “hours at a time” as we tried to avoid submersion while wading into deeper water. Finally, we became adept at swimming.

From there he sees us developing into a fully aquatic creature–

“..diving for shell fish, prising out worms, burrowing crabs and bivalves from the sands at the bottom of shallow seas, and breaking open sea-urchins, and then, with increasing skill, capturing fish with [our] bare hands.”

Only after improving our tools and hunting techniques would we, the now aquatic apes, have been sufficiently equipped to venture back onto land and into the savannah.  In the evolutionary process, Hardy surmises, we would have lost most of our body hair in the way of dolphins and whales.  As we pursued deeper and faster prey we would have developed a more streamlined body than other primates.

Hardy cites professor Frederic Wood Jones’ Man’s Place Among the Mammals (1919). That book, he says, caused him to first consider aquatic origins thirty years earlier.   In his book, Wood Jones wonders why, unlike other primates, humans’ body fat is attached to their skin—a distinction, Woods Jones reminds readers, which is “familiar enough to everyone who has repeatedly skinned both human subjects and any other member of the Primates.”

This brief observation was enough to trigger Hardy, an expert in Antarctic biology, to think about blubber – that thick layer of fat that insulates and protects marine birds and mammals.  Hardy realized that an aquatic origin would answer the question of the body fat along with many of the other questions that had been raised about the differences between humans and our brethren, the great apes.  The more Hardy thought about an aquatic origin, the more it seemed that this theory could be a missing link in our understanding of human evolution.

In the end, Hardy’s thesis was politely ignored by the scientific community. In fact, it probably would have fallen into obscurity if not for Desmond Morris and subsequently, a little-known Welsh television screenwriter – Elaine Morgan.

Although not trained in science, Morgan was no slouch academically. She held a degree in English from Oxford. She was a screenwriter of enough talent to merit a tidy collection of prestigious awards. She was inquisitive enough to have read Morris’s book and then bold enough to publicly question it.

Human fat akin to blubber? Hardy thought so.

Morgan took issue with Morris for being too male-centric in his assumptions about how humans evolved our unique behaviours and phylogeny. In her mind, his explanations elucidated nothing about why women evolved many of the same attributes as men and why both sexes are so different from other apes.  As a challenge to Morris’s assumptions, Morgan wrote her first book, The Descent of Woman: The Classic Study of Evolution (1972) where she publicly took him to task.

But despite her differences with Morris’s theses, there was one point on which she and Morris were in agreement – on that “ingenious theory.” In that one short passage Morgan recognised a truth—that the Aquatic Ape Theory, if proved out, would shake the foundation that supports all of our current thinking on human origins.  That premise, Morgan decided, neatly explained everything that makes us unique as primates— our hairlessness, our bipedalism, our streamline bodies. From the moment of that realization Morgan became a passionate promoter and, for the next forty years, the sole torchbearer for the AAT.

When The Descent of Woman was released, Morgan braced herself for backlash. She knew her criticism of Morris was tendentious, but it was, after all, 1972. Women’s Lib was in the air. In such a zeitgeist she would not have been surprised if 50% of the population disagreed with her. But her real anticipation was over her discourse on the AAT. For this she expected criticism of the scientific sort. First, she foresaw an attack on her qualifications to even address the subject; who was this screen writer pretending to know a thing or two about evolution and human origins? She also recognized that her attitude in her book was, at best, flippant and that her research was superficial. She assumed that the scientific community would step forward en force to tear down her entire thesis.

Instead, like Hardy, Morgan was ignored.

A savvy woman, Morgan knew better than to take this as a win. Silence in the scientific world is an ominous sign, not a victorious one. Besides, she was looking for scientific scrutiny. She wanted enough critical response so she could either concede that she was misinformed or build a better case.  Since neither of these happened, and because she’s not the type to crawl quietly back into her hole, Morgan decided to take up the cause in earnest.

After giving herself a crash course in evolutionary studies, Morgan released The Aquatic Ape in 1982. This work was blessed with a Forward written by the illustrious Sir Alister Hardy himself. In it Hardy reminds readers that:

“..some of the greatest contributors to evolution theory had no academic training in biology.”

The Aquatic Ape carried a more serious tone than Morgan’s previous book and supplied what she considered to be more evidence in support of the AAT.  Again, to her surprise and dismay, her work was met with silence from the academic community.

Hot and dusty human origins?

But the public was captivated.  By 1987 Morgan had generated enough interest in the theory that a conference was organized by the European Sociobiological Society and the Dutch Association of Physical Anthropology. Held in Valkenburg, Netherlands, the purpose of the conference was to try to determine which niche humans must have filled in order to evolve so differently from other apes—was it the savannah or the sea?

Raymond Dart’s savannah hypothesis was the prevailing theory at the time. For this reason, AAT was held up as a competing theory to Dart’s—“Cold and Watery” or “Hot and Dusty” was how anthropologist Vernon Reynolds phrased it in the title of his summary of the proceedings. The conference was well-attended by enthusiasts representing both sides of the argument, with lines forming outside the doors to many of the popular lectures. Twenty two participants representing the full range of support and opposition to AAT presented papers.  Together they covered such topics as primate behaviour, marine ecosystems, geophysical history, cultural anthropology, and physiological differences between apes and humans.

..or cold an watery?

After a long day of civil disagreement in what the authors of the proceedings called a “fair and friendly atmosphere” the scientists ultimately came down on the side opposing the Aquatic Ape Theory.  As summed up by Vernon Reynolds, “while there are a number of arguments favouring the AAT, they are not sufficiently convincing to counteract the arguments against it.”   In fact, several former supporters of AAT concluded that the evidence against the theory was stronger than that for it.

So that should have put an end to AAT.

But today at 88 years old, Morgan still carries the torch for human’s aquatic origins.  Since The Aquatic Ape, she has written four more books on the subject. She’s a popular and engaging lecturer, has been interviewed on television, and was featured in a BBC documentary.  She tells audiences that she wants AAT dissected argument by argument, evidence by evidence, the way any other scientific theory would be.  And, she quips in her 2009 TED Lecture, referring to her own advanced age, “sooner would be better than later.”

What Morgan doesn’t seem to realize is that with so many hundreds or even thousands of trained eyes looking at AAT over the last forty years, if it held any water at all, a good number of anthropologists would have excitedly jumped on board. Instead, while her credentialed supporters include the likes of medical doctors, geologists, geographers, and nutritionists, none are paleoanthropologists—the very experts she is hoping to sway.

When I first read about the Aquatic Ape Theory, I was skeptical. More than skeptical – I rejected the idea outright.  If humans had passed through a portion of our recent evolution in the sea, why weren’t scientists talking about it? And besides, who was this woman? The term crackpot came to mind. Or opportunist—she certainly has sold a lot of books on the subject.  How can she know more than all the scientists who have been studying human origins for the past century?  (Always a pseudo-science red flag) I was prepared to join the rank and file of detractors and grant her a single dismissive paragraph when I started this piece.

But then I watched her 2009 TED lecture – and I liked her!  Sure, I still reject her theory, but Morgan is easy-going and engaging. She’s funny. She’s smart.  She comes across as anything but a crackpot.  And that charisma has everything to do with why her long-debunked idea is still circulating. It got her on TED didn’t it? It’s not her theory everyone loves –it’s her.

And in response to that, I’ll leave you with the very apt words of anthropologist John Hawks:

Is the Aquatic Ape Theory fairly described as pseudoscience? Every statement of natural causes is potentially scientific. What distinguishes science from pseudoscience is social. Pseudoscience is supported by assertions of authority, by rejection or ignorance of pertinent tests, by supporters who take on the trappings of scientific argument without accepting science’s basic rules of refutation and replication. Pseudoscience is driven by charismatic personalities who do not answer direct questions. When held by those in power, like Lysenkoism, it destroys honest scientific inquiry. When held by a minority, it pleads persecution.  I think that the Aquatic Ape Theory in 2009 fits the description.

So yes, the water is lovely Ms. Morgan. Entirely lovely. But it was never our home.

Writing Away at Writescape's Spring Thaw Retreat at Elmhirst's Resort

I just came from a lovely weekend writing retreat.  Two and a half days in a cottage on a lake; mealtimes with other writers; the sharing of work; walks on the lakeshore; an evening glass of wine by the fireplace with friends – but most importantly many hours of uninterrupted writing time. Almost 3,000 words worth.

A retreat seems a bit like overkill for someone like me whose only work is writing and whose office is at home.  Ok, sure, I manage our household, but it’s not like that takes an inordinate amount of effort.  My family is supportive, self-sufficient, and immensely helpful. They do not need me.

So, excuses aside, I have plenty of opportunity to write.

Dining Room Table Office

I do much of my writing on my laptop in one of my three home offices –  the dining room table office with its east-facing sunny windows, right near the coffee and perfect for mornings.  And there’s the comfy chair by the fireplace office, great on damp grey afternoons and snowy winter nights. Plus it’s right near all my books. And there’s the back deck office – ahhh, those summer days in the shade of big maples, surrounded by birdsong and lawnmowers.

And there is nothing wrong with any of these places, except this: They are all at home.

Now if you are a writer, I don’t have to tell you what that means. For the rest of you ..

It’s the distractions. They’re everywhere. And when they’re not, we make them up.  (Am I right?)  Distractions are what save us from a particularly sticky paragraph, a character that just won’t behave, an essay that’s about to collapse upon itself, or most importantly, from the Dreaded Blank Page.

Fireplace Office

Far easier to clean behind the fridge, I say.

And I do. Right after I throw in a load of wash, remember to thaw chicken for dinner, look for a recipe that we aren’t sick of, email my sister to see if she has that one we had at her place last summer; Oh look! She’s online, let’s chat by Gtalk instead. Might as well check Twitter while I’m here. (So much for that hour.) Oh gosh, I need to water the plants. And clean up this sticky spot in front of the fridge, and surely it’s time to change the furnace filter, plant a garden and rotate the tires …

Wow, is it 3:00 already?

No, to write away is the only answer.

Writing Away at the Library

So I write away at the library a couple times a week. That’s where I do the heavy lifting  – working on the essays for my book and delving into the good solid science blog posts .  I also sometimes write in coffee shops, at the zoo, or just out in nature, places where the more freely creative work happens. And yes, I have written some fine material in those places.

But to write away at a retreat, well that is a whole other thing. It’s an immersive experience. Writing is not only what you do there, it’s what you talk about, what you learn about, and what you share.  All of the little diversions of life melt away and there is a measure of focus that carries across days instead of hours. Suddenly you find yourself writing really great stuff—the stuff that books are made of.

So sure, you can write anywhere – even at home. As long as you have the tools of your trade, a bit of quiet (or not, if you prefer the buzz of life surrounding you), and some uninterrupted time, you can get the job of writing done.

And that’s what I’ll keep telling myself … until my next opportunity to write away.

Well, not exactly the cover of the Rolling Stone.. but even BETTER!  Here’s the fabulous cover design for The Best Science Writing Online 2012.  (Design by Jason Heuer)   Go ahead, click it and make it big!

Look at me! I’m hanging with the cool kids!
So now let’s get some of that Cover of the Rolling Stone feeling… all together now …

And as far as warmth and protection are concerned, there is a good deal of the virtue of wool in such a snow-fall. How it protects the grass, the plants, the roots of the trees, and the worms, insects, and smaller animals in the ground! It is a veritable fleece, beneath which the shivering earth (“the frozen hills ached with pain,” says one of our young poets) is restored to warmth.  (John Burroughs, “Signs and Seasons” )

Here in Southern Ontario the winter of 2011-2012 was the winter that wasn’t.  Temperatures were off the top of the charts and we hardly got any snowfall to speak of. Every time it did snow, the snow was followed by rain, so we were back to bare ground within days.  I think I shoveled my driveway exactly twice – and it would have melted anyway.  I’ve lived north of the 43^rd parallel for more than 25 years and I can safely say I have never seen a winter like this.

“It has been a summer to remember. In winter.” – Joe Romm

My garden, March 15, 2012

And I’m not alone.

According to NOAA, snow cover across the US and Canada was the third smallest in the 46 years of the satellite record.  Across the lake, in Buffalo, NY the normal expectation is that 2/3 of winter precipitation will be snow and 1/3 rain. This year they had 80% rain.

Now for many people this was great!  No scraping ice from the windshield. No shoveling the driveway. No messy commutes, school closings, or flight delays. For those of us in the north, it was like having March every day. For some, it was more like July.

“It’s 86 degrees in Los Angeles today [Wednesday, January 4th],” says Patzert. “Everyone thinks it’s July! In fact, it’s warmer today in LA than it was on July 4th last year.

Covering up to 50% of the earth, snow cover is important for a whole bunch of reasons [pdf] having to do with climate and water:  It has a major effect on surface albedo (reflectivity) and thus affects atmospheric thickness and surface temperature. Snowmelt plays an important role in the seasonal energy exchanges between the atmosphere and the ground, so in turn, affects water resources.

Winter snow cover is the most extensive element of the cryosphere and plays a fundamental role in climate.  (from Roger G. Barry: Snow Cover)

But there is another interesting thing about snow cover–something right at our feet.

Imagine walking through a snow-covered clearing in the forest.  Except for the footprints of squirrels, rabbits, and maybe a deer, the clearing seems largely empty.  But here’s the thing you don’t see: That snow you’re walking on contains a world of living creatures. In fact, without snow, there is an entire winter ecosystem missing from the environment – the nivean world – that is, the world in, on and under the snow.

Take, for instance, the subnivean world — the small space that is created between the snow cover and the earth.  Protected by a wooly blanket of snow, the subnivean space has its own climate. Once the snow reaches about 15-20 cm deep, it provides enough insulation to keep the temperature there between -10C and 0C.  This creates a comfortable refuge for a whole community of tiny winter-actives– those creatures that do not hibernate or migrate during the winter.

This is not a place where cold little animals huddle in shivery groups struggling to bear out the winter. It is a busy place. Intersecting tunnels bustle with mice, voles, moles, beetles, spiders, and grubs. There are sleeping quarters, nurseries, food storage sites, and even latrines. And along the ground, mats of fungi and colonies of bacteria break down organic material.

Masked Shrew (James F. Parnell, nps.gov)

Field mice run about and fetch seeds and berries they cached during the fall. Meadow voles nibble on plant stems, bulbs, and the occasional snail. Shrews, manic little creatures that require constant calories to power their frenetic lifestyle, devour insect pupae, larvae and eggs.  If they run short of those delicacies, shrews will dig into their stored cache of live food –voles or mice that they have paralyzed with venom to keep fresh.

Entire generations are reared under the snow. Voles and deer mice build communal nests lined with leaf-litter, fur, and dried grasses.  With enough adults and offspring huddled together, temperatures in the nursery can reach a balmy 10C.

Of course all this activity doesn’t go unnoticed to alert animals on top of the snow.  Occasionally the muffled underworld is penetrated by a calamity from above. A slight crunching of snow .. a pause..silence..then crash! Two large feet smash through the snowy ceiling and a vole meets its end in the jaws of hungry fox.

Ermine -- beautiful fearsome predators (Greg Scott, Wisc Dept Nat Resources)

Other times the threat comes from within. In Southern Ontario, ermines (aka short-tailed weasel; mustela erminea) expertly hunt subnivean tunnels for meadow voles. They are efficient predators, grabbing their prey (which may be larger than they are) by the head and wrapping their lithe bodies around the victim to hold it still long enough to impart a lethal bite to the jugular. Not only do they eat their prey, but since ermines have given up winter insulation (fat and long coats) in favour of flexibility and speed under the snow, they  pluck fur from their victims to line their own dens.

But overall, the subnivean world is a protected one. The greater danger comes with not having it. A lack of snowfall can be disastrous to the animals that normally winter beneath the snow.

Under normal conditions, voles and mice undergo regular population fluctuations. Field voles in Sweden, for example, cycle on a 3-4 year basis. But that cycle has become interrupted in the last 40 years.

Scandinavian studies have found that the winter decline of vole populations has increased in frequency and severity for several species (Clethrionomys rufocanus, C. glareolus and Microtus agrestis) since the 1970’s.  That is, fewer animals are surviving the winter. This appears to be linked to “decreased winter quality” — a phenomenon that includes later than usual snow cover, lower snow depth, and earlier and/or frequent mid-winter snow melts.

Vole runways remain after the snow melts (S. Vantassel)

In other words, it’s not harsh winters that kill voles, it’s mild ones.

The exact reason hasn’t been pinpointed, but there are several factors that are suspected of playing a role – increased predation due to loss of cover, loss of stored food,  increased environmental stress leading to disease,  decrease in food quality, and simply, exposure to cold.

In addition, the irregularity of snow cover and melt can lead to direct mortality of subnivean animals.  Under normal conditions, the most dangerous time for subnivean species is spring. Warmer weather means snow melt, which means water percolating down through the snow into the cavities below. This constant drizzle can cause animals to get wet and die of hypothermia or even drown as water starts running through tunnels.

The weather we had this past winter resembled spring over and over again, with cycles of snowfall followed by rain.  Not only would this create excessive water, but the subsequent refreezing would fill tunnels, food storage sites, and entry/exit holes with ice.

So, as much as our spring-like weather made the winter easier for humans and some animals, it may have meant a serious decline of some subnivean populations. And that, in turn, may have a detrimental effect on owls, raptors, foxes, and weasels and other predators that prey on subnivean animals.

So let’s hope for a good snowy winter next year.

Hörnfeldt, B. (2004). Long-term decline in numbers of cyclic voles in boreal Sweden: analysis and presentation of hypotheses Oikos, 107 (2), 376-392 DOI: 10.1111/j.0030-1299.2004.13348.x