Spoor Identification

The art of tracking involves each and every sign of animal presence that can be found in nature, including ground spoor, vegetation spoor, scent, feeding signs, urine, faeces, saliva, pellets, territorial signs, paths and shelters, vocal and other auditory signs, visual signs, incidental signs, circumstantial signs and skeletal signs. In this book only footprints are dealt with in detail, as they are the easiest to identify. Footprints provide the most detailed information on the identity, movements and activities of animals, and once a trail has been identified, other signs can be studied in more detail. Footprints therefore offer a valuable introduction to the art of tracking, a science that might otherwise prove inaccessible to the inexperienced naturalist.

The examples of spoor provided are of particular individual animals which are assumed to be representative of that species. Where variations occur, several examples have been included with an indication of how many individuals that have been studied they present. Ideally one should have an indication of the percentage of a large sample population each variation represents, but that would require much more data.

The illustrations are exact studies of spoor made under ideal conditions, such as wet sand or dusty ground. A calliper was used to take measurements of every detail and its position relative to two right-angled reference lines, to ensure the highest possible degree of accuracy. Field studies were supplemented by photographs and studies of museum specimens. The feet of ungulate specimens, which are assumed to have retained the shape and size of the outer walls of the hooves, were also traced. (The fact that two groups of !Xõ trackers of the Kalahari correctly differentiated the male and female Kudu spoor based on specimens suggests that the shapes of the hoofs of specimens do not change significantly.) In some cases where the spoor of rare antelope were not found, reconstructions of what their spoor should look like have been based on specimens. Spoor reconstructed from specimens are indicated by (S). Since it is conceivable that at least some of the specimen hoofs may have changed shape, these are subject to further research.

The spoor illustrations may be regarded as generalised models that have been used to simplify spoor interpretation. In reality one will probably never find two animals with exactly identical footprints. One therefore needs abstractions to identify characteristic features of the spoor of different species.

A further advantage of using models is that it gives one a preconceived image that improves the chances of recognising spoor that may otherwise be overlooked. Preconceived images play an important role in the recognition of patterns in nature. However, with a preconceived image in mind, one tends to 'recognise' patterns in markings that may have been made by other animals, or even random markings (like seeing faces in clouds). One must be careful not to be prejudiced and see what one wants to see.

While species may be recognised by some general characteristics, each individual animal's spoor differs in very subtle ways, and it is in principle possible to identify an individual animal from its spoor. So, for example, Kalahari trackers can identify the antelope they have shot from the rest of the herd and will track down that individual animal. Apart from the functional and environmental adaptations of the species, an individual animal's spoor may vary according to its age, mass, sex, condition, and the terrain as well as random variations. It may also have a unique way of walking or a peculiar habit that distinguishes it from other animals.

While the spoor of most of the larger mammals and birds can be identified as belonging to a particular species, the spoor of the smaller animals may only be identified as belonging to a genus, family or order. The smaller the animal, the more difficult it becomes to distinguish its spoor from that of similar species, and while some mammal families may consist of only a few species, insect families may contain thousands of species. Some of the antelope species may have spoor characteristics typical of the species, but variations may occur that are similar to those of other species.

Steenbok spoor, for example, are usually sharply pointed with straight sides, while Duiker spoor are normally more rounded. However, some Steenbok may have spoor similar to typical Duiker spoor, and vice versa. A small antelope spoor that has a typical Steenbok shape could therefore only be identified as probably Steenbok, but possibly also Duiker, unless other evidence rules out either possibility. Kalahari trackers can, for example, distinguish a Steenbok spoor from that of a Duiker, even in soft sand where the shape of the hoof is not clear, by the way they tread. Steenbok tread with their hoofs pointing down into the ground, while Duiker tread in a more flat-footed way. Furthermore, the presence of droppings may indicate the species, since Steenbok normally bury their droppings while Duiker do not.

In the case of gregarious animals, especially ungulates, the whole group should be studied to determine the typical spoor and variations in the group. The majority of spoor in a group would probably be representative of a typical spoor characteristic of the species, while unusual variations would form a minority.
The best footprints are usually found in damp, slightly muddy earth, in wet sand, in a thin layer of loose dust on firm substrate, or in snow. Ideal wet conditions are found along streams, rivers, waterholes, dams , vleis, beaches, after rain or in the morning when the sand is still damp from the dew. Puddles that have just dried out, leaving a thin layer of mud over a firm substrate, are ideal for tracks of small animals. Dirt roads and paths may have a thin layer of very fine dust on firm ground that can reveal the finest detail of the spoor.

Usually, however, footprints are partially obliterated, and one should walk up and down the trail to find the best imprints. Even if no clear footprints can be found, one can collect bits of information by studying several footprints and piece them together to compile an image of the complete spoor.
When studying spoor in loose sand, one should try to visualise the shape of the footprint before the loose sand grains slid together to obliterate the well-defined features. As much information may be lost in loose sand, it is not always possible to distinguish the spoor of similar species, so it would have to be considered as belonging to any one of several possibilities, until further evidence is gathered.

When loose wind-blown sand has accumulated in a footprint that was made in damp or wet sand, it is sometimes possible to carefully blow away the loose sand to reveal the features of the spoor underneath. Footprints in mud may in fact be preserved for quite a long time underneath a layer of loose sand. In blowing away the sand, great care must be take not to destroy the footprint itself. When leaves are covering the spoor, or even when the animal has stepped on top of leaves, they can be carefully removed to reveal the spoor underneath.

It should be kept in mind that footprints may be distorted owing to slipping and twisting of the feet on the ground. When the animal is walking on a slope or running, the feet may slip, so the spoor will appear elongated or warped. If the fore and hind spoor are superimposed, it may look like an elongated spoor, or the toes of the fore footprint may be confused with those of the hind. When trotting or running, the animal's mass is supported mainly on the toes and only pat of the intermediate pads may show, or, in the case of mongooses, the proximal pads may not show at all. On hard ground padded toes may not show and only claw marks may be seen.

If the spoor could be that of several possible species, the distribution maps in this field guide should be consulted to eliminate those that do not occur in that locality. Habitat and habits, such as sociability and daily rhythm, as well as feeding signs and faeces, should also be considered to narrow down the range of possibilities.

The best way to learn how to recognise a track is to prepare an accurate sketch showing its exact dimensions. This compels one to note all the details of the track and therefore to remember them better. Use a calliper to measure the dimensions and position relative to two right-angled reference lines of each detail. Care must be taken that distances measured are always perpendicular to the reference lines (see Fig. 1). A calculation pad with 5 mm squares is ideal for drawing spoor. As reference lines, place two rulers at right angles to each other next to the spoor (use a corner of your sketch book as a right angle). For ungulates it is easiest to place a thin knitting needle, with markings every 5 mm, down the middle of the spoor, and to measure the distance of the edge of the spoor from the needle every 5 mm (see Fig. 2). Note that antelope spoor are not exactly symmetrical. For bird spoor it is easiest to draw reference lines down the middle of each toe, using the arms of the calliper to measure the angles between them (see Fig. 3).

SpoorIDFig1 SpoorIDFig2

SpoorIDFig3

In measuring a footprint, the length is taken from the front edge of the longest toe's pad mark to the hindmost edge of the intermediate pads. If the whole footprint can be seen, a measurement to hindmost edge should also be taken. The claws are not reckoned in the total length, as they may vary in length according to wear, and are measured separately. The breadth is measured at the broadest part of the footprint. When measuring the track left by a cloven hoof, the distance between the tips of each half of the hoof and, if possible, the length of the toe pads should be measured in addition to the length and breadth. When measuring bird tracks, the length of the central toe and the first toe should also be taken. For accuracy it is best to measure tracks made when the animals was moving slowly. In rapid locomotion the feet tend to slip and the tracks will therefore be a little too large.

When measuring a group of tracks it helps to stretch a piece of string between tow pegs so that is runs through the centre of the group parallel to the direction of movement; use this as a reference line. The distance from this line to the middle of the front edge of each footprint should be measured and recorded on a sketch. Additional measurements should include the length of a single group of tracks, the stride length and the straddle width. The stride length is the distance from the front edge of the foremost footprint in a group to the front edge of the corresponding footprint in the following group. Note that the stride length is not always constant, as an animal may give a few short strides and then a long jump. The straddle width is the width of the track group, and is the sum of the distances to the reference line of the outermost tracks on both sides. The sketch should show which are left- and right-foot, fore- and hind-foot tracks. If some of the tracks are turned outwards, the angle made by their midlines with the reference line should be shown. It is convenient to use paper marked in millimetre squares so as to draw the relative position to scale.

A quicker method, although not as good, is to take a photograph. It is essential to include a scale in the photograph and to take it directly from above so that the picture will not be slanted. Slides can be put into an enlarger, by means of which one can project a natural size image of the spoor into paper, enabling one to make an accurate tracing. An 80-200 mm zoom lens with a macro facility is very useful for photographing spoor of various sizes (except for very large spoor such as that of Elephants).

Another method is to prepare a collection of casts in plaster of Paris. This method has the advantage that it preserves a copy of the actual spoor, which can be referred to afterwards. For demonstration purposes reproductions of the original footprint can be made using the cast to form imprints in sand.

Compared to photographs and casts, drawing footprints has the advantage that details of several partially obliterated footprints (of the same foot of the same animal) can be collected and put together to create a composite, complete footprint. Very fine detail will also be recorded that may be lost in a photograph because of imperfect lighting or may not show up in a plaster cast. For people who cannot draw accurately, however, photographs and plaster casts will be the most accurate. Drawing footprints accurately is also very time-consuming and requires a lot of patience and considerable concentration. It usually takes me at least an hour to draw a fore-foot and hind-foot of an antelope, whose spoor is relatively simple. More complex footprints may take longer. In order to distinguish subtle variations in spoor, such as the difference between male and female animals, a very high degree of accuracy is essential.

An easy way to compare similar spoor is to trace the outline of the spoor illustrations on transparent tracing paper and to place it over similar spoor to see how they differ. In the process of tracing you will get to know the spoor's distinctive features, which will help you recognise them in the field.

Note that spoor illustrations printed natural size, or close to natural size, appear to be larger that the actual spoor on the ground. This is due to an optical illusion created by the greater contrast between the black ink and white paper, compared to the more subtle shadows in the actual spoor on the ground. This discrepancy should also be kept in mind when drawing spoor, since one tends to draw it smaller that the actual size to make it appear the same size. It is therefore essential to measure each detail of the spoor.

Spoor identification not only requires a great deal of knowledge, but also skill and experience. Although the inexperienced naturalist should in principle be able to use this book to identify near-perfect spoor in ideal conditions, the accurate identification of imperfect spoor, especially in loose sand, may only be possible after considerable experience. Furthermore, the footprints in this book should only be regarded as providing a basic introduction to spoor interpretation , and every opportunity should be take to study all other signs in order to master the art of tracking.