Exploring The Last Green Valley: Curious springtails are the snow fleas of winter

I was about 10 years old the first time I discovered snow fleas, or what are really called springtails.

The large pile of wet snow underneath the old oak tree in our yard was perfect for making snowballs, but my plan to ambush my brother was thwarted by of all things, the insect world.

As I approached the tree I noticed what looked like a sprinkling of black pepper on the snow. Suddenly the black dots launched into the air in front of me. Bugs! What in the world were they doing outside in the winter?

I stood in awe as thousands of tiny black snow fleas hopped about on the melting snow — their black bodies standing out against winter’s white carpet.

Nowadays I’ll look for them when the conditions are right — usually about this time of year and during a mid-winter thaw.

If the weather is a bit warm and the snow is slowly melting, you can find them in yards or in the woods, especially on snow that has built up against the trunks of large trees.

What are snow fleas, where do they come from, and how in the world do they jump so high?

I went looking for some answers and found several informative sources on these tiny critters of winter.

In particular, I found a wonderful essay on springtails by naturalist and author Bill Amos in “The Outside Story, Volume 2” published by Northern Woodlands.

“Six thousand species of springtails populate the world and the snow fleas we see in New England are but one variety,” he writes. “They have cousins living afar in leaf litter, tree canopies, and on rocky shores. They can be found in dark caves and in sunny meadows, and on ice in Antarctica and warm lava on a Pacific island. They are practically everywhere. They have been here a long time, too, but have changed little over the ages. Fossils reveal that springtails existed 400 million years ago.”

When we see snow fleas, we usually see them by the thousands, and in fact more than 100,000 of them can comfortably live in one square meter of soil.

They typically live in moist locations with rich organic matter at ground level such as leaf litter and soils of the forest floor. When they tunnel up through the snow we can more easily see their dark bodies against the white of the snow.

Dark in color, a 16th of an inch long, with three pairs of legs, two antennae and two clusters of eyes with 16 in each, springtails are unique and certainly do look like fleas.

Their small legs are used for moving about but it is the furcula, or lever-like appendage under the abdomen, held in place by a two-hook clasp, that is their most unique characteristic.

When disturbed (such as by a young boy looking for perfect snowball snow) they will release the clasp and spring into the air. And spring they do – like superman leaping tall buildings in a single bound, these super creatures jump hundreds of times their body length.

Springtails feed on a variety of materials, including fungi, soil bacteria, mold spores, algae, pollen and organic material.

Springtails are everywhere — on rocks, on water, and especially in leaves or under logs. They are very susceptible to desiccation and must spend most of their time in very moist locations.

Most of the year springtails go undetected, minding their own business on top of the soil and leaf litter.

It is during their winter wanderings up through the snow to feed on pollen or algae that they appear, and the name snow flea suddenly makes sense.

If the conditions are right, the weather is warm, and the snow is wet, you might come across a large number of these tiny creatures on top of the snow.

Step lightly, and keep your distance, or you just might send a jumping cloud of snow fleas into the air.

We live in a beautiful place full of unique and amazing creatures. From the largest black bear to the tiniest snow flea, our natural world awaits our curiosity and wonder. I invite you to enjoy it, share it and help pass it on to the next generation.

Bill Reid is chief ranger of The Last Green Valley National Heritage Corridor and has lived in the region for 35 years. He can be reached at bill@tlgv.org.

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