Have you been walking, hiking, or skiing this winter and noticed large patches of snow covered with tiny black specks? Especially in depressions like shoe prints, ski tracks or tree wells? Dirty snow, right? Or maybe an early bloom of spores? Well, in January, February, and March, during some warm winter spells, what you actually were seeing are snow fleas. Incredibly small — measuring in at only one-sixteenth of an inch — snow fleas look like specks of dirt or pepper or ash, but when you see something moving, you know you’re not looking at soil particles. Rather, hundreds or thousands of snow fleas. Not only moving, but jumping!

Snow fleas launch into the air by the discharge of a retractable forked tail-like appendage, tucked under their body, called a furcula. When the springtail releases tiny hooks that hold the furcula in place, ca-boing! Thus their alias name “springtail.” Since they’re wingless, this is how they get around, by walking or suddenly popping off the snow; it also aids in “fleaing” predators: beetles, spiders, ants, mites, and centipedes. Check out the video titled Jump! Go Ahead, Jump, Little Springtail of springtails somersaulting through the air, in slow motion, on insectsdiditfirst.com. According to the video, springtails can eject themselves into the air up to six inches off the ground, “equivalent of a human being jumping over the Eiffel Tower.”

Snow fleas are not actually fleas. Fleas are parasites, organisms living off another organism; snow fleas live off decaying organic matter such as fungi, moss, and algae in the soil or on top of snow. Because they break down matter, they’re considered decomposers. They also don’t bite like fleas. There’s a running debate if they can be classified as insects because their body is slightly different than that of the standard insect. Snow fleas are considered hexapods — hex meaning six; snow fleas have six legs — a species of arthropod, an invertebrate animal of the large phylum Arthropoda, such as an insect, spider, or crustacean. Arthropods have a segmented body, jointed limbs, and a shell that molts. They’re similar to fleas, however, in their hopping capability.


The reason we’ve been seeing large snow flea populations on top of the snow in February and March is that the sunny and warmer days entice them from the ground to the surface of the snow to eat algae that grow on decomposing leaf litter on melting snow. The reason they don’t freeze on the snow is an antifreeze-like protein. According to the Ecological Society of America, as reported in a study published in Biophysical Journal, “Snow fleas are able to withstand the bitter temperatures of winter thanks to a glycine-rich antifreeze protein.” The protein in the snow fleas binds to ice crystals as they start to form, preventing the crystals from growing larger. Snow fleas are antifreeze flying acrobats! They are not solely winter creatures though; they hang out in leaf litter the rest of the year, or, according to Cornell Cooperative at St. Lawrence County, on the surface of ponds “where surface tension keeps them from sinking.” It’s just easier to see the tiny black specks against the stark background of white snow.

A patch of dirty snow might just be a patch of dirty snow. But it also might be a congregation of snow fleas engaging in one wild party, gorging on algae, and showing off their gymnastic skills. Never underestimate nature. These are some rambunctious bugs.  

Do you have a question about our region’s environment? Email editors@moonshineink.com.


  • Eve Quesnel

    Eve Quesnel has lived in Truckee for 35 years with her husband Bill, once-upon-a-time daughter Kim-now on her own-and many dogs through the years, currently a Border Collie-Aussi mix. Her favorite pastimes include walking in her neighborhood and nearby woods, hiking in the high Sierra, and reading and writing. Quesnel is now retired from teaching English at Sierra College in Truckee but continues to pursue several writing projects. She is intrigued by the natural world of which she explores and writes about for the column "Nature's Corner" in Moonshine Ink.

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