Walk Softly - Winter Critters

by Geoffrey Carpentier 

A late winter forest can feel quiet on the surface, but if you pause beside a patch of softening snow, the season reveals a world which is anything but still. As the sun climbs higher and the snowpack thins, life begins to stir in places most of us never think to look. This is the moment when winter’s “sleepers,” and “movers” begin to reappear. These are creatures which have spent months tucked beneath the snow, waiting for the first hints of warmth to call them back into motion.

What draws them out is a subtle shift in the landscape? When snow melts slowly and new snowfalls are scarce, the surface becomes a canvas for snow algae, sometimes called watermelon snow for its faint pinkish tint. This alga thrives in the cold and, in turn, attracts grazing insects from the leaf litter below.

If you look closely at the snow, near open ground, you may notice what appear to be flecks of dirt scattered across the surface. At first they seem inert, but then—one jumps. Then another. These are snow fleas, though the name is misleading. They are not fleas at all, but springtails, members of an order of invertebrates which may be among the most abundant on Earth. A single hectare of healthy forest soil can hold up to 25 million of them, though most of the year they remain hidden in the damp darkness of leaf litter and soil.

Springtails are marvels of miniature engineering. Each one carries a spring loaded forked spine tucked beneath its tail. When released, this tiny catapult can launch them up to 10 centimetres into the air—an astonishing feat for a creature only one or two millimetres long. Imagine a human long jumper clearing 200 metres from a standing start. Their sudden leaps make them seem to vanish, only to reappear a moment later in a different patch of snow. For a few weeks each year, these tiny acrobats become some of the most visible creatures in the forest, and their presence is a sign of healthy, living soil beneath the snow.

Where there are grazers, predators are never far behind. Scorpionflies, small, wingless insects, only a few millimetres long, venture onto the snowpack in search of springtails. Despite their name, they are neither true scorpions nor true flies, but they are efficient hunters, moving with surprising speed across the cold surface. Nearby, one might also see wingless winter crane flies, delicate insects with long legs which give them a spiderlike appearance. Although they look fragile, winter crane flies are built for the cold. Their adult stage exists only in winter, and while scientists still aren’t entirely sure what they eat - if they eat at all - they are a regular part of the snowpack community. True spiders also patrol the snow in late winter, their dark bodies visible against the white background. They move deliberately, pausing often, their legs testing the surface for vibrations. For them, the snow is a hunting ground rich with small, cold-tolerant prey.

Near open streams and rivers, another winter specialist makes its appearance. Winter stoneflies begin to emerge from the icy water. By emerging so early, they avoid many of the predators which will arrive later in spring. Their presence is a quiet but powerful indicator of a healthy stream - clean, cold, and well oxygenated.

All of this activity takes place in the subnivean zone, the hidden space between the ground and the bottom of the snowpack. Insulated by snow, this zone remains relatively warm, compared to the air above, allowing insects, mice, voles, and other small creatures to move and feed even during the coldest months.

When late winter arrives and the snow begins to soften, the boundary between the subnivean zone and the surface becomes porous. Creatures which have spent months in darkness begin to venture upward, drawn by sunlight and food.

Beneath the snow, life persists in ingenious ways and when the spring takes over from winter, these small, cold-loving creatures are the first to remind us, winter is not an ending but a bridge to the quiet beginning of the year’s next chapter.

Geoff Carpentier is a published author, expedition guide and environmental consultant. Visit Geoff on-line on LinkedIn, Facebook and Instagram.