Reading tracks in snow, mud, sand and dust

A print is created by the interplay of three things: the foot, the movement and the substrate. Soft, damp, fine-grained ground gives way under the foot and keeps the shape, much like play dough. Loose or coarse ground, by contrast, trickles back as soon as the foot is gone and loses the fine details. How fast the animal was moving also changes the print: running pushes soil backwards, slipping distorts the print.

Snow is a special case because it keeps changing after the print is made. Sun and wind thaw or blow away the edges; the track becomes bigger, rounder and blurrier. When new snow falls, it fills old tracks. If a track thaws and refreezes at night, it can become hard and glassy. That is why two tracks of the same animal on a sunny slope and in the shade often look completely different.

On hard ground, dust or tarmac, a foot leaves hardly any depth, only tiny differences in the surface: flattened dust, shifted grains, a damp print. These are best seen in raking light – light that falls very low across the ground. Then even the smallest bumps and dips cast shadows.

Mud and clay often show the finest details: individual toe pads, claws, sometimes even skin texture. The best prints are often found at the edges of puddles or on stream banks, where the ground is damp but not liquid. Because animals slip easily in mud, you should always compare several prints before forming a judgement.

Sand varies greatly with moisture. Damp sand shows the shape quite well, dry sand usually only an outline, because the grains trickle back. Wind blurs sand tracks quickly. The early morning hours are therefore often the best time: animals active at night have left fresh tracks, and the wind is often still light.

In snow, depth and age matter. Best are a few centimetres of fresh snow on a firm base – then the print is clear. In deep snow animals sink in and individual prints say little; then the whole trail pattern – spacing, arrangement and width of the trail – is more informative. Thawed tracks are always bigger than the foot that made them.

Raking light is your most important tool. Hold a torch or headlamp very low over the ground, almost at ground level, and move it slowly back and forth. Or use the low sun in the morning and evening. Look at the print from different directions – sometimes it only appears when you move around it. In midday sun from above, by contrast, you see almost nothing.

An excellent exercise is your own tracking plot: a smoothed area of sand or soil in the garden. Here you can watch how the same species – often it is the neighbour's cat – prints on different days and at different moisture levels. You can also press your own hands or shoes into different substrates and compare.

For each track, note the substrate, how damp it was, the temperature and the weather since the last rain or snowfall. These details often explain later why a track looked bigger, smaller or different than expected. Experienced trackers collect comparison images of the same animal in different substrates over years.

The best tracks are often exactly where the ground is unsafe: on banks, on frozen water, on tidal flats or in bogs. Banks can be undercut and collapse, ice can be thinner than it looks, and mud can hold you fast. Never follow a track onto ice or into tidal flats or bogs. On tidal flats the tide also comes in, often faster than expected.

There are risks indoors too. Tracks in dusty attics or cellars often come from mice or rats. Their droppings and urine can contain pathogens that can be inhaled with the dust. So do not stir up dust, wear a mask and gloves if needed and wash your hands afterwards.

The classic winter mistake: a thawed track is taken for that of a much bigger animal. That is how many stories about huge animals in the snow arise. So always compare tracks on the sunny and shaded sides and check whether the edges are sharp or rounded.

Just as common: looking at only a single print. A print can be slipped, smudged or overlaid by a second one. Only several prints in a row give a reliable picture. In leaf litter and grass, by the way, hardly any clear prints form – there you read disturbance signs instead, such as overturned leaves or flattened grass.