An All-Star Nose

The chickadee took its time choosing a seed. Perched with its tiny toenails pricking the pad of my finger, it cocked its black-capped head this way and that. With its precisely pointed beak, the bird picked up a sunflower seed from my palm, weighed it for a split second, and then tossed it aside. That hull must have been empty.

It tried again. The second seed passed muster, and as the chickadee turned to fly away, its buff-colored belly feathers brushed my thumb. I held my breath-- hoping to enjoy the touch of soft down -- but my cold, calloused skin barely registered a wisp of sensation. Instead, I got one last poke with spiny toes as the chickadee launched back to the tree.

Its times like this I wish I were a mole. Strange, I know, but I don’t mean just any mole. I wish I were a star-nosed mole – because they have the best sense of touch of any mammal. They may also be the weirdest looking mammal, and those two things are related. Star-nosed moles get their name from 22 fleshy, pink tentacles that protrude from the tip of their otherwise featureless face, which is on the end of a plain gray, oblong body, flanked by paddle-like digging feet with long, stout claws.

Each tentacle gets its bumpy texture from over 25,000 touch receptors, called Eimer’s organs. Each Eimer's organ contains three types of tactile receptors, two of which also exist in human skin. The third type is unique to the star-nosed mole, and allows the mole to identify objects by their microscopic texture. This funny nose is the most sensitive organ in the entire animal kingdom. If I were a mole, I could have enjoyed even the microscopic softness of those chickadee feathers.

If I were a mole, a vast portion of my brainpower would be devoted to processing tactile information, and I could only see light and dark. I would also eat earthworms. So, maybe the benefits don’t outweigh the drawbacks. But star-nosed moles are incredibly well adapted for their own lives, if not mine.

Those super-sensing tentacles allow star-nosed moles to touch more than twelve objects per second, creating a tactile map of the environment under their nose. They can “see” without light as they tunnel through moist soil. Sometimes those objects are food, and it takes less than one fifth of a second (14 times faster than any other mole) for the star-nosed mole to realize that something is edible, and then eat it. That is much faster than my seed-weighing chickadee. This skill puts it in the running for the world’s fastest eater, right up there with a high school cross-country team at a pasta feed.

Star-nosed moles are even adept at swimming and foraging under water. This came as a HUGE surprise to me, the first time I encountered this amazing creature. I was snowshoeing on a lake in northern Minnesota on a very cold day, when I saw something dark on top of the snow. We were very confused. Moles live underground, and survive the winter by following the worms even deeper underground, right?

Wrong -- at least for star-nosed moles. These crazy creatures are active throughout the winter, burrowing through snow and even swimming under the ice of frozen ponds. I can relate. The same winter I found the icy mole, I also dug snow caves and jumped into frozen lakes.

Unlike me, moles use their excellent sense of smell to find prey under the water. Mammal noses don’t usually work very well under water, because we must inhale air to bring scent molecules in contact with cilia in our nasal passages. To make the life aquatic work, star-nosed moles exhale several bubbles per second onto objects or scent trails they encounter under water. When the moles draw the bubbles back into their noses, the scent molecules in the air contact olfactory receptors, and wa-lah! They can smell underwater.

So what good are these little creatures, aside from giving us something to be awed about in the dead of winter? Their tunnels loosen the soil and provide aeration for the roots of plants. Their voracious appetites can help control pest insects, and they provide protein snacks for a wide variety of predators. Owls, weasels, and even largemouth bass ignore the odd appearance of star-nosed moles long enough to gulp them down the hatch.

Star-nosed moles may not be as cute as my chickadees, but they can certainly make us appreciate the limits and abilities of our five senses. Mary Oliver describes moles as “pushing and shoving with their stubborn muzzles against the whole earth, finding it delicious.” I find the earth delicious in so many ways, don’t you?

Snowshoes

With every step, I sank eight inches into wallowing fluff. Lifting each leg awkwardly to take wide, encumbered strides, I was nonetheless glad the I wasn’t post holing all the way to the leaf litter, over two feet down. A trackless trail through the snowy woods will make anyone appreciate snowshoes pretty quickly!

Five inches of fresh snow, with more dancing in the air, had dissuaded me from skiing, so I strapped the shorter and wider version of winter gear on my feet for an evening walk.

Snowshoes aren’t a new idea, of course. My plastic and aluminum models, with pop-up heel props for climbing mountains, jagged metal crampons under the balls of my feet, and easy-pull straps, are simply the most recent technologies. According to one source, snowshoeing’s origins lie in the deep snows of Central Asia. Early humans brought snowshoes across the Bering Strait when they migrated to North America. Countless cultures have used them since--as a means of survival.

“This is the snowshoe which is as necessary in winter as the canoe in summer. Through the whole of North America, all the warriors, hunters, traders, travelers, church goers, men, women and children, move about at that period in snowshoes.” Wrote Johann Georg Kohl in his 1860 book, “Kitchi Gami: Life among the Lake Superior Ojibway.” The snowshoes that Mr. Kohl writes about were made of bent wooden frames laced with rawhide straps.

The main benefit of snowshoes, of course, is that by distributing your weight over a wider surface area, snowshoes provided mobility and flotation in deep snow. But not everyone needs wood, metal, or plastic appendages to get the job done. The earliest snowshoes, from at least a couple million years ago, are found already attached to the Canada lynx and the snowshoe hare.

The hare’s six-inch-long hind feet allow it to stay on top of deep snow. But the lynx has feet four inches across, so it can follow and catch a hare.

With less snow on the ground, however, lynx lose their advantage. It becomes harder to compete with other mid-sized predators like pine martins, fishers, and coyotes. The lynx’s own cousin, the bobcat, is its fiercest competitor. These days, where you find bobcats, you just do not find lynx.

Lynx and hares don’t have a monopoly on snowshoe feet, though, and other species are free to produce their own. Ruffed grouse grow projections off the sides of their toes in winter, making them look like combs. The projections act as snowshoes to help grouse walk across snow.

Many other winter-active northern animals have extra-large feet, even if we might not think of them as snowshoes. Fishers have large hind feet. Moose have huge hooves when compared to a deer, and are more suited for deep snows. Wolves have large feet, and often increase their surface area by splaying their toes in deep snow. In March--the “snow crust moon” in Ojibwa culture—the wolves’ feet really start to outperform the deer’s dainty toes.

For these animals, the advantage that snowshoes provide is a matter of survival.

I huffed and puffed uphill through the snow for about thirty minutes on my snowshoes before arriving back at home. When I left the house, I’d been debating between going outside or taking a nap! Now, my blood was flowing, my cheeks glowing, and I felt alert, calm, and in love with life. Research has proven what I felt: to keep our brains at peak performance, our bodies need to work hard. Exercise improves brain function, mood, and attention, reduces anxiety, depression, and stress, and protects again the effects of stress and aging.

My snowshoes might not help me catch dinner or escape predation, but they provide me with access to the winter world, and give me tool for improving my health and happiness.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI, at 13470 County Highway M. The current exhibit, “Deer Camp: A Natural and Cultural History of White-tailed Deer,” opened in May 2013 and will remain open until April 2014.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com/.

The Jewels of Summer

Bitter winds blow across a frozen landscape, but under the ice hide the jewels of summer.

Even during an Arctic cold snap, many quick-flowing and spring-fed rivers maintain an open channel of inky current. This meandering passage often follows the thalweg (one of my favorite words), which is the deepest channel of the riverbed, usually with the swiftest flow. The input of relatively warm groundwater may help prevent ice formation, as does the constant churning of molecules. Even the still waters of lakes and ponds remain liquid below, insulated by the layer of less-dense ice floating on top.

Except for the ice fishermen’s prey, we often forget that anything lives in the dark depths below the ice and chilly water. But crawling around on the river bottoms are some of the most grotesque, fearsome, and ancient predators you may ever encounter. Come summer they will emerge from the depths, shed their gruesome shells, and take flight as shimmering-winged dragonflies.

Understandably, you don’t see those colorful acrobats this time of year. Most dragonfly species do not overwinter as adults. The ones that buzzed your cheek and caught a ride on your canoe paddle? They’re all dead, their genes (hopefully) passed on to the next generation. Common green darners are an impressive exception, as they fly more than a thousand miles to Mexico or Florida with other snowbirds. A few species overwinter as eggs, frozen neatly into the stems of aquatic plants. But most spend the winter hidden under the ice on our lakes and streams, as alien-like nymphs.

Nymphs are the immature stage of insects that go through gradual or “incomplete” metamorphosis. The alternative is “complete” metamorphosis, which is what butterflies do when they enter the inactive pupal stage and then transform abruptly to a flying adult. Dragonfly nymphs shed their skin several times as they grow through stages called “instars,” until finally they emerge as a flying adult.

Dragonfly nymphs may spend anywhere from four weeks to several years growing through the instars. The cooler and shorter the summers are where they live, the longer it takes. In the meantime, they rule the river bottom as fierce predators.

Their hydraulic-powered hunting system is not for the squeamish. To catch food, a nymph draws in water through its anus, and clenches its abdominal and thoracic muscles against the water-filled rectal chamber. The amazing amount of pressure now trapped inside the nymph’s body cavity pushes out its labium, or toothy lower lip, in a high-speed strike. The lightning attack may earn the tiny predator a meal of tasty mosquito larvae, a tadpole, a small fish, or even another species of dragonfly nymph.

The dragonfly nymph’s hydraulic system isn’t just used for hunting. By jetting water out the way it came in, nymphs can propel themselves forward at a speed of 10 centimeters per second. That power of acceleration can help when they are on the hunt, and also allows for quick exits if they become the hunted. Smallmouth bass, for example, might love a nymph for lunch.

As the water goes in and out, it passes by gills in the dragonfly’s rectum, and helps the little critter absorb oxygen. This constant filtering of the stream through their bodies means that dragonflies can’t survive in streams polluted by heavy metals, agricultural runoff, and sewage. Dragonfly nymphs make excellent water quality indicators.

If they survive the winter, dragonfly nymphs will use the abundance of spring and summer to continue growing through their required eight to seventeen instars (depending on the species) before their final mutation into adulthood. The metamorphosis is astounding. From a split down the back of a scraggly, brown, bottom-feeder emerges a colorful, fairy-like being with delicate, dexterous wings.

Their beauty belies the power they retain as a predator. Separate muscles control each wing, and enable dragonflies to swoop acrobatically, move straight up or down, fly backwards, stop and hover, and make hairpin turns – all at full speed or in slow motion.

Huge eyes take in a 360 degree view and allow them to lock onto a moving target, judge its trajectory, and intercept it – with a 95% success rate. Dragonflies’ spiky legs, a relic from their previous life as a water monster, form a net to snag prey on the wing. Those prey include our old friends the mosquitoes, who are (at the moment) “out of sight, out of mind.”

The dragonflies themselves are a bit hidden right now, creeping along the river bottoms and lake beds beneath the ice. They are waiting just as we are – lying low until they can tear off their heavy shells and bask in the warmth of the sun. If you saw one, would you recognize it as a diamond in the rough? Could you imagine it soaring as a jewel of summer?

“I want to think again of dangerous and noble things. I want to be light and frolicsome. I want to be improbable and beautiful and afraid of nothing as though I had wings.”

― from "Starlings in Winter" by Mary Oliver

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI, at 13470 County Highway M. The current exhibit, “Deer Camp: A Natural and Cultural History of White-tailed Deer,” opened in May 2013 and will remain open until April 2014.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com/.

New Exhibit Opening May 2014: Nature's Superheroes

Peregrine falcons fly with super speed, dung beetles move objects with super strength, dragonflies fly with super agility, gray tree frogs disappear with their cloak of invisibility, and bats use super senses to catch prey.  The real accomplishments of these incredible creatures deserve the same respect as the antics of our favorite comic book heroes. Not only that, but they all face their own type of kryptonite, and need your help as superhero sidekicks! The Museum’s 2014 exhibit, “Nature’s Superheroes” will focus on the “superhero powers” of plant and animal adaptations to get kids of all ages excited about nature. 

Color Vision

Even a wash of golden afternoon sunlight couldn’t seem to warm the icy air. I put my head down and skied harder, hoping to send warmth to my fingertips. Despite being out in full sun—a treat after several weeks of skiing only at dusk-- the woods seemed stark and colorless. Soon a steep hill came to my rescue, and as I churned up it determinedly, I could feel my extremities turning warm and pink under their protective layers.

Now I could relax a bit, and look around. With greater awareness, it seemed that color had seeped into the woods just like it had seeped into my fingers. Blue sky shone through the intricate pattern of twigs, although it paled gradually toward the horizon. The trees themselves revealed complex mosaics of browns and grays. Thin stripes of orange, even, lay in the bottom of the deep furrows low on big tooth aspen trunks. Clinging to the bark was a whole other palate of pale green, gray green, sage green, and sea green lichens. A few unique lichen species glowed with summery shades of tangerine and goldenrod.

The peeling bark of young birch trees exposed innocent, peach-colored skin. A granite boulder, not quite buried in the snow, added a splash of coral pink. Through the understory, the buds of red maple trees lived up to their name, and dogwood twigs matched their scarlet hue. High in those brown twigs, silhouetted against the blue sky, the bright red crest of a hairy woodpecker livened up his otherwise black and white feathers.

When we look close enough, color is everywhere -- even in the winter woods. But what if we didn’t have to look so hard? What if the world glimmered with twice as many – or a million times as many -- hues?

It’s hard to imagine, but not every creature is limited to the same basic seven colors we see. We think of “visible light” as those wavelengths between 380 nanometers to 760 nanometers. Those are the electromagnetic waves that the cone cells in our eyes perceive as violet, indigo, blue, green, yellow, orange, and red. Humans have three types of cone cells – red, green, and blue – that each absorb light in overlapping sections of the spectrum. We perceive the intermediate colors when light is absorbed by two types of cone cells at once. For instance, we see yellow when the red cones are stimulated slightly more than the green cones. In this way, we can see a few hundred hues.

Birds, as well as some species of fish, amphibians, reptiles and insects, however, have a fourth type of cone cell that allows them to see wavelengths of light down to 300 nanometers, which includes the ultraviolet section of the spectrum. This means that the animals see wavelengths beyond those of a typical human being's eyesight, and may be able to distinguish colors that appear identical to humans.

What does ultraviolet look like? We don’t know!

We do know that things like flower petals, feathers, caterpillars, beetles, and moths reflect light in the ultraviolet spectrum, and seeing UV light gives critters an advantage in finding food and attracting mates.

While UV radiation is invisible to the human eye, illuminating certain materials with UV light causes the objects to fluoresce, and re-emit light at a slightly longer wavelength. The UV light is altered enough that it becomes visible light, and we see things glow. I think that this is how a black light works when it makes your white t-shirt glow.

In addition to seeing beyond the spectrum of human vision, birds can see more colors within our normal range as well. They accomplish this first by having a higher density of photo receptor cells than humans, and then by having a drop of colored oil on each cone cell. The oil droplets act as light filters, and reduce the range of wavelengths that can trigger each cone cell. This increases the precision of their color vision, and allows them to distinguish between more subtlety different hues.

With their four types of color receptors, birds are considered “tetrachromats” as opposed to humans, who are “trichromats” with three color receptors. Incredibly, pigeons and some butterflies are “pentachromats” with five color receptors, and, the ability (theoretically at least) to distinguish up to 10 billion colors. Talk about a different way to see the world!

Now, before you get too jealous, you should know that such stellar color vision has its drawbacks. Birds who focus on color vision have poorer night vision and must roost after dark. That’s why the woods are so silent on our starlit hikes. Humans, on the other hand, have the versatility to see both in bright sunlight and nearly total darkness. We also can move our eyes within our sockets, and use binocular vision to aid in depth perception, something that many birds cannot do. In addition, birds devote a greater proportion of their brain volume to visual processing, at the expense of their senses of smell and taste.

It might be exciting to see a million colors, but it might also be a little overwhelming. I don’t think I’m willing to trade the scent of wood smoke or the taste of chocolate to try it out. I’ll leave the visual bonanza to the flock of chickadees chattering overhead. Instead, I’ll appreciate the subtle beauty of blue-gray tree shadows laying brush strokes across the trail, and enjoy the fact that I can still see well enough to ski as the dusk falls on another winter day.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI, at 13470 County Highway M. The current exhibit, “Deer Camp: A Natural and Cultural History of White-tailed Deer,” opened in May 2013 and will remain open until April 2014.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com/.