What Are Snow Fleas?

Snow fleas sitting atop the snow.

Robbie Sproule/Flickr/CC BY 2.0

For the bug enthusiasts among us, it's a happy day when we find snow fleas. At the end of a long, cold, nearly bug-free winter, we feel lucky to find a mass of tiny arthropods hopping about in the melting snow. Snow fleas are actually not fleas at all, but a kind of springtail. Because they're tiny and tend to jump, they remind people of fleas and thus were given this inaccurate name.

What Do Snow Fleas Look Like?

From even a short distance away, snow fleas look like bits of dirt or pepper on the surface of the snow. They catch people's attention because they have a habit of jumping. At times, snow fleas gather in such large numbers they make the snow look black or blue. They tend to aggregate on the surface of the snow around the trunks of trees.

Take a closer look, however, and you'll find that snow fleas look similar to other springtails. They're quite small, reaching only 2-3 millimeters in length. The springtails we find flinging themselves across the snow are usually blue in color. In North America, the snow fleas we're likely to find belong to the genus Hypogastrura.

Why and How Do Snow Fleas Jump?

Snow fleas are wingless insects, incapable of flying. They move by walking and jumping. But unlike other famous jumping arthropods like grasshoppers or jumping spiders, snow fleas don't use their legs to jump. Snow fleas catapult themselves into the air by releasing a spring-like mechanism called a furcula, a sort of tail that's folded underneath its body — thus the name springtail. When the furcula releases, the snow flea is launched several inches in the air, a considerable distance for such a tiny bug. It's an effective way to flee potential predators quickly, although they have no way to steer.

Why Do Snow Fleas Gather on the Snow?

Snow fleas live in the soil and leaf litter, even in the winter months, where they munch away on decaying vegetation and other organic matter. Springtails are actually quite common and abundant, but they're so tiny that they tend to blend in and go unnoticed.

Remarkably, snow fleas don't freeze in the winter thanks to a special kind of protein in their bodies. This protein is rich in glycine, an amino acid, which enables the protein to bind to ice crystals and keep them from growing. It works much like the antifreeze we put in our cars. The antifreeze protein allows snow fleas to remain alive and active even in subzero temperatures.

On warm and sunny winter days, particularly as we get closer to spring, snow fleas make their way up through the snow, perhaps in search of food. As they gather in numbers on the white surface, flinging themselves from place to place, they attract our attention.

How Do I Get Rid of Snow Fleas?

Why would you want to get rid of snow fleas? They're perfectly harmless. They don't bite, they can't make you sick, and they won't hurt your plants. In fact, they help improve your soil by breaking down organic material. Leave them be. Once the snow melts and spring arrives, you'll forget they're even there — unless you like bugs, in which case you may find yourself searching for them in the soil.