What's tiny...less than 1/8 of an inch, ancient... fossil records date back 400 million years, and on mild sunny days of late winter they sprinkle the snow surface like pepper? SNOW FLEAS! But don't start itching yet.
Snow Fleas (Achorutes nivicolus), as they are commonly called, belong to the insect order Collembola, and they are not really fleas at all! Fleas, like the Common Cat flea, belong to the order Siphonaptera. Fleas are body parasites and have piercing and sucking mouthparts...as your family pet may well know! Snow Fleas on the other hand are completely harmless. They are one of 314 species of Springtails in North America. Springtails are aptly named for a jumping apparatus at the end of their abdomen. Two spring-like tails called a 
":furcula" are tucked under the abdomen of the insect and are held in place by "hooks". When the insect wishes to move it simply releases this spring-loaded appendage which pushes against the surface of the snow and propels the insect upwards. Once airborne, this wingless creature cannot control its direction of travel and often lands back where it started. Snow Fleas are herbivorous and feed on decaying organic matter, microscopic algae, bacteria, and fungi. Snow Fleas contribute to the process of soil-building and are therefore a valued component in a healthy forest ecosystem.
Last spring I was truly honored to come across a mass migration of Snow Fleas moving across PEEC's Tumbling Waters Trail. Mass migrations of Snow Fleas are known to occur, but for disputed reasons. In this case, I witnessed three large ash-like conglomerations of Springtails in the middle of the trail. The groups were literally over an inch deep, eight inches wide and perhaps 26 inches long. As a whole, the mass appeared to be stagnant, but once down on hands and knees the movement of individuals created the effect of a miniature black cloud swirling and tumbling in chaos. I lowered my head for closer inspection only to recoil quickly as I began inhaling mouthfuls of this Snow Flea cloud. Yet I was so intrigued by what was transpiring before me that I just had to reap the full benefit of such an encounter. I delicately pushed my right hand and arm into the migrating hysteria until it became totally submersed in a flurry of Snow Fleas. The sensation of these insects leaping on and off my bare arm, springing from my arm hair like a diving board, was nothing short off...well....strange.
Snow Fleas can be found year round on the surface of ponds, under the leaf layer on the forest floor, and other various places. However they go largely unnoticed, as do many of nature's smaller delights. It is believed that the Snow Flea absorbs the sun's heat and enables it to function at near freezing temperatures. On sunny mild winter days, look closely at the snow surface or at the base of trees where the snow has been melted and you will surely see what you have been stepping on all along.
