The Little Mysteries In Nature

THE LITTLE MYSTERIES IN LIFE  

February/March, 2008 issue

As we hit the trail at daybreak, there were moments when we both felt that our faces were beginning to slide off the sides of our heads. The brisk wind off the nearby lake cut through our coats, and efforts to photograph some of the sights were brief. After such a mild winter leading up to this particular day, a normally tolerable minus seven degrees with a minus 13 degree wind chill somehow felt much colder.

Suddenly, the shelter of a deciduous woodlot blocked the unrelenting breeze and the walking became more pleasant. It was then that our dog spotted something in the path. It was small enough that even I had to get down on my knees to see what it was that had suddenly captured her attention. It was a rodent-like creature of some sort, but appeared as only a tiny round ball of smooth slate grey fur, coiled tightly where it had died, probably in the night, caught by the sudden freeze and unable to find shelter.

The animal was a shrew, but what species was unclear as it was surely frozen solid. There are 11 species listed for Canada, but fewer than half of them can be expected in our area. The shrews belong to an order that also includes moles, a sort of wastebasket into which small primitive mammals of uncertain affinities have been unceremoniously dumped. The order is call Insectivora, and as the name suggests, they are largely insect eaters, so they are not rodents, although superficially they may resemble one.

In my collection of “props” that I often take with me on guided hikes, is a preserved pigmy shrew. My wife prefers not to know about any dead animals I might have stashed away in my office, but I keep this one, simply because it is the smallest mammal in North America. It currently resides in one of those miniature sample jam jars, and its small form never fails to amaze participants on hikes when I take it out of my backpack. It is not known how this one died, but it was given to me many years ago by a friend who lives on Highway 33, east of Picton. The Atlas of the Mammals of Ontario (1994) says, that while the pigmy shrew ranges across Ontario, fewer sight records were obtained for this species than for any of the remaining five species documented. Other shrew species treated in the book included smoky, common, water, short-tailed and least shrews.

Shrews are always in a highly revved up state, and with this high metabolic rate, they feed almost constantly when not sleeping, so are active all winter. It is little wonder they live for only 18 months, or so. Their  eyes and ears are not well developed, so they depend largely on their sense of touch and smell to get around and find food. Shrews are not my area of expertise, so I still have no idea what this species was that we found in the centre of the trail.

The order also includes the moles, and among the strangest in this family is the star-nosed mole. These weird little creatures occasionally turn up on our front lawn, getting most of their information about the environment around them by the numerous nasal tentacles around the nose. As it roots around, these tentacles are cleverly folded over the nostrils to keep dirt from entering the nasal passages. There are actually 22 of these little symmetrical finger-like tentacles. Count them the next time you find a star-nosed mole. Like the shrews, its eyesight is relatively poor, but why have good eyesight when the only thing to look forward to is the next grain of dirt ahead of you?

If the nose wasn’t peculiar enough, the tail of the star-nosed mole is even more so. It is long and fleshy with a noticeable basal constriction, somewhat scaly and during the summer, covered with unsightly hairs. But in the winter, the tail becomes thick with stored fat, and becomes greasy to the touch. Not an animal you might want to keep as a pet and cuddle up close to on cold nights.

There are only two other moles that we can expect to find in our area area – the eastern mole and the hairy-tailed mole. Then there are the voles, but that’s another story, and another entirely different family.

Meanwhile, the shrew that our dog found, and subsequently lost interest in, still lay in the centre of the trail. I picked it up and dropped it to the side of the trail where it bounced and rolled down the side of the embankment like a small stone. We talked about the shrew for several minutes during our walk, wondering what circumstances had contributed to it ending up in the centre of the trail where it was exposed to bitter temperatures. Had it been looking for food during the night, then lacking any measurable success, succumbed to the cold as it took a break by curling up, and never recovered?

As we explore local trails this winter, no matter how knowledgeable we think we are, we will encounter mysteries. If you are a good wildlife detective, you may be able to get a feel for the chain of events that has led up to any discovery made. A fellow naturalist  I am acquainted with is able to not only identify animal tracks he finds in the snow, but after careful examination, determine whether the animal in question is in pursuit of something, or itself being pursued – information gathered from just looking at the pattern of the tracks. It comes with experience – lots of experience, but even he admits to becoming stumped at times. The challenges of being a wildlife sleuth.

Tracks that we can determine to be mouse tracks are most likely those of a meadow vole because we know that only white-footed mice or deer mice foolishly travel atop the snow. For a meadow vole to come out, even briefly, is certain suicide, so it depends on creating a labyrinth of grassy tunnels below the snow surface where it is safe. However, a major thaw like we had in early January exposes these tunnels and their occupants, much to the delight of hawks and night hunting owls. One section of our lawn was a mosaic of tunnels during the thaw in early January – tunnels I was completely unaware of when snow was on the ground even though I passed by that area regularly.

So many mysteries. Bird migration, for example, is mysterious enough, but we assume that after birds have done it a time or two, they should  know the way, somehow. But how do the juveniles of shorebirds find their way from the Arctic to wintering grounds in Argentina, when they set off by themselves, long after the adults have made the journey? How do this winter’s redpolls know there is food down here when their natural supply in the boreal forests has run out, and moreover, how do they know enough to gravitate to feeders for niger seed, a food that they have never tasted in the north, never mind knowing what a feeder is all about?

Some mysteries will remain mysteries, and as it should be. How absolutely dull the study of nature would be if we knew the answers to everything!  It’s these kinds of discoveries that lend interest to the interpretive  hikes I lead every year. These little discoveries are  tiny, almost insignificant fragments in the greater scheme of things. They are reminders of how little we do really do know about the natural world around us.