Science

Classification of Signs

Spoor

Spoor includes a wide range of signs, from obvious footprints, which provide detailed information on the identity and activities of an animal, to very subtle signs which may indicate nothing more than that some disturbance had occurred.

Clear footprints in soft ground supply the most detailed information on the identity and activities of an animal or person. Perfectly clear prints are seldom found, though, and usually only fragments of prints or partially obliterated prints are evident. Fresh footprints usually show up slightly darker in colour than the surrounding ground. On hard ground where there may be no definite indentations, footprints may appear as shiny patches of dirt because of the change of reflective properties of the ground. Scuff marks in the shape of scraped patches normally stand out as a different shade from the surface around them. In walking across ground ant then stepping on rocks, an animal may transfer some dirt onto the rocks.

When wind and rain build up soil deposits around a pebble, a little crater is formed which becomes visible when the pebble is dislodged from its socket. A freshly turned pebble or stone will generally appear different in colour, usually darker, from surrounding stones. A pebble that has been stepped on will have been imbedded in the ground.

If a small twig or dry branch is stepped on, a depression in the ground directly beneath it will normally be visible. Dead twigs and branches on the ground may be broken or cracked. To determine if the fracture is recent or old, similar twigs can be broken and compared.

A freshly turned dry leaf will appear darken in colour as the shaded part is exposed, compared to the sun-bleached surrounding leaves. Some mud may also cling to the side that was underneath. When the ground is covered with dry leaves, a trail of crushed leaves may be left behind when an animal has passed along. Where leaves lie thick and impressions made on them do not show at all, it may be possible to scrape them aside to examine the earth underneath.

A very distinct path will be made when tall grass or similar vegetation is bent in the direction of travel. Grass trampled or flattened presents a shiny surface to the sun; this makes the route followed a lighter colour that the surrounding grass. When an animal moves through dense bush or reeds, branches or reeds will be pulled in the direction of travel and some interlacing may occur when they are released. Displaced at an angle, bent or broken vegetation may have different reflective properties and appear different in colour.

Where dew or frost occurs, or after rain, the uniform distribution of droplets or ice will present a shiny surface. In these conditions an animal will leave a distinct path that will show up as a dark line where the ice or drops have been shed.

When an animal crossing a stream had to step into the water, water or wet mud may be displaced from the stream. If the river bottom can be seen, disturbed mud or overturned rocks or stones may be detected. Close to the water's edge, soft mud may also leave clear impressions.

Broken cobwebs may indicate that an animal moved through an opening between bushes; conversely, cobwebs across an opening indicate that an animal did not move through it. Disused holes in the ground are usually indicated by cobwebs across the opening, while occupied holes will be clean.

Scent

Animals produce secretions that leave a trail perceptible to the sense of smell. Scent-making can also be carried out with urine and faeces. All animals that track follow scent, while humans, who do not have a good sense of smell, have to use dogs.

Scent is influenced by temperature and weather. Cool, calm conditions may help to preserve scent, while heat and wind may erase the scent trail. Conditions are better in the morning and evening that at midday, and also better in winter than in summer. Wet ground provides more favourable conditions than dry ground, but rain may obliterate scent. Scent also diminishes with time, so that dogs must follow a relatively fresh trail if they are to locate their prey.

When very close to them, experienced trackers can sometimes smell and identify animals such as Elephant, Buffalo, wildebeest, zebra, Waterbuck, Giraffe and Lion before they have seen them. After it has rained for a few days, when the air is very humid, a tracker may also be able to scent animals if the wind is right. Fresh droppings and urine also have a distinctive smell.

Faeces and urine

The easiest way to identify droppings is to look at fresh droppings associated with fresh footprints, since footprints are usually easier to identify than droppings. Apart from watching animals produce droppings, this is also the best way to learn how to recognise droppings. To document faeces adequately would require several colour photographs for each species, since may variations may occur for a particular species and even for a single individual, depending on what it has been eating and on its physical condition. Furthermore, many species produce droppings which have the same general shape, so the shape and size may not be enough to identify droppings as belonging to a particular species. In this section only the general characteristics of droppings are discussed.

Where the animal has already been identified by its footprints, droppings and urine may provide additional information in the interpretation of spoor. Fresh urine and faeces can give an indication of the age of the spoor, while a detailed examination of faeces may reveal what the animal has been feeding on. The position of the urine patch relative to the footprints can indicate the sex of the animal. For example, an antelope urinates with its hind-legs straddled, thus indicating where the animal was standing. The urine patch of the male will lie between the tracks of the fore-feet and the hind-feet, whereas that of the female will be between or behind the hind-feet tracks. The relative position of a urine patch to faeces deposited at the same time can also indicate the sex of the animal. If one looks at the footprints to determine the direction the animal was facing, a urine patch in front of the faeces usually indicates a male, whereas a urine patch on top of or behind the faeces usually indicates a female.

SignsDroppings

Where footprints have been obliterated or on hard ground where footprints are not clear, it is usually more difficult to interpret droppings by themselves. To identify them one needs to consider their shapes, sizes, colours, consistency, contents, the manner it which they were deposited and the context within which they are found. The shape and size of the droppings of some animals are so distinctive that they can easily be identified as belonging to a particular species, such as those of Elephants, rhino, Hippo, Buffalo and zebra. Sometimes the shape may not be distinctive, but the size may distinguish them, such as those of Lion or Giraffe which are bigger than other droppings of similar shapes. In some cases a few species may have similar droppings, such as the two hyaena species. However, the general shape and size of droppings may often be characteristic of a large number of species.

While the large, round droppings of Elephant, rhino and Hippo have the same shape, they are unmistakable. Those of the Elephant are the largest and those of the Hippo the smallest, while rhino use middens. The droppings of Black and White Rhino can be distinguished by their contents.

All the small antelope species produce droppings that have the same general shape and may vary only slightly in size. The same applies for medium-sized and large antelope. Giraffe droppings have the same shape as antelope droppings, but are larger. Antelope droppings generally consist of large number of small, round pellets, pointed at one end with an indentation at the other end. Sometimes they occur in clusters of pellets sticking together. Hare, Springhares and dassies also produce small round pellets, although they do not have the same shape as those of antelope.

While the droppings of zebra have a very distinctive, regular shape, those of Warthogs, which are similar in appearance, have an irregular round shape. While most vegetarians generally have round droppings, those of Porcupine are cylindrical and pointed at one end.

The faeces of carnivores are usually cylindrical or sausage-shaped, with a point at one end. The droppings of hyaenas, however, are usually irregular round shapes, often sticking together. Omnivores, such as Baboons and Honey Badgers, also produce droppings that are generally cylindrical in shape.

In cases where the general shape of the droppings is the same, the size may vary according tot the size of the individual, whether juvenile or adult, or the size of adults of a species. The size of herbivore droppings may also vary according to their liquid content. In the dry season the liquid will be less and the droppings may be much smaller that in the wet season. Droppings also shrink as they dry out, so old droppings may be much smaller than fresh droppings.

The consistency and shape of droppings may depend on the composition of the food. Lush grass may produce soft, sometimes liquid faeces, whereas dry grass produces hard, dry droppings. The consistency may also depend on the condition of the animal. An individual that is ill or under stress may produce droppings that are runny.

The contents of droppings will reveal what the animal was eating, which may be characteristic of various species. The contents of the droppings of a grazer can be distinguished from those of a browser. The droppings of carnivores may contain hair and pieces of bone. Carnivore droppings, especially those of hyaenas, may turn white if they have a high calcium content. The droppings of otters and Water Mongooses contain bits of crab shells. Civet droppings may contain the remains of millipedes, insects, bits of fur and bone, and wild fruit pips. The droppings of Antbears and Aardwolfs consist mainly of sand which is swallowed with ants and termites.

The manner in which droppings are deposited may also help to narrow down the possibilities. Some animals scatter their droppings randomly, while others use middens. Some bury their faeces, while others use it for scent-marking their territories, in which case it may be deposited in an elevated position so that the scent is effectively disseminated.

Finally, the context within which the droppings are found may help to identify the animal. Animals that do not occur in that locality can obviously be ruled out, while it can be expected that an animal's droppings will usually be found within its preferred habitat.

Saliva

Saliva may sometimes be seen on leaves where an animal was feeding or on the ground at a salt lick. Fresh cuds may also be found on the ground.

Pellets

Many birds regurgitate those parts of their food which they cannot digest in compressed pellets. These may contain fur, feathers, chitin from insects, bones, pieces of mollusc shell and undigested plant material, and will often be covered with mucus. Some birds produce almost spherical pellets, while others produce cylindrical pellets with one or both ends rounded or pointed. Since each species has certain food preferences, the contents of the pellets may help to identify the species concerned. The location where the pellets were found would also be within the preferred habitat of the species; this will often help to narrow down the possibilities. Pellets are usually found at birds' roosting sites and nests, and sometimes in feeding areas.

Feeding signs

Depending on one's detailed knowledge of the diets of animals for a particular area and time of the year, feeding signs could help to identify spoor. Diets are very complex, however, and more than one animal can eat the same food. The remains left by large carnivores are usually also utilised by smaller carnivores and scavengers. Conversely, if the identity of the animal is already known from footprints, then feeding signs may give an indication of what that animal has been eating.

Feeding signs can also help one to follow a spoor. In the case of browsers, if it is known which bushes the antelope has a preference for, the tracker may leave the spoor and go to the next bush where the antelope may have been feeding. Feeding Elephants may leave a trail of broken branches. Circling vultures can also help one locate feeding predators.

Most animals prefer to remain hidden when feeding, and may take their food to a special feeding place where they can be safe while feeding. Some animals may have feeding places out in the open. The larger carnivores, for example, have nothing to fear, while animals such as squirrels may position themselves in places from which they can detect an approaching enemy at a distance.

Apart form the choice of food, evidence in the form of marks left by the teeth or beak and methods of handling the food may also give an indication of the animal involved.

Vocal and other auditory signs

Vocal signs such as alarm calls can warn either the tracker of his or her quarry of danger. Since an alarm call usually alerts all other animals in the vicinity, trackers must be careful not to let other animals betray their presence. The Grey Lourie, Corythaixoides concolor, or 'go-away' bird, a source of annoyance to trackers, utters a loud drawn-out 'go-away' call when disturbed, and will often follow or fly ahead of intruders, thus alarming the quarry. Baboons may alert other animals by loud barks, and a Kudu may give a short bark before running off. Guineafowl may also frighten animals by rising and clacking.

A disturbance can also be indicated by the absence of vocal signs, such as the sudden silence of chirping crickets.

Other auditory signs include rustling grass or bushes, the crushing of leaves, the breaking of twigs and branches, stones and pebbles kicked in flight, splashing water or galloping hoofs. Depending on the quality of the sound, it may be possible to distinguish between a light and a heavy animal, or between one that is moving slowly and another moving swiftly.

Visual signs

Apart from actually seeing the animals itself, visual sign would include all signs of movement where the animal may be hidden from view. An animal's presence will often be betrayed by moving bushes or long grass. A fleeing animal may only be detected by the sudden movement of branches. When the slow rustling sound of a Crocodile in tall reeds is heard, its position could be indicated by the moving tips of the reeds. Or the presence of a Crocodile under water can be detected by small bubbles rising to the surface.

Incidental signs

Incidental signs are signs which may not necessarily be associated with the spoor in question. Such signs include tufts of hair, feathers or Porcupine quills. It should be noted that although tufts or hair or feathers may belong to the animal in question, they could have been blown there by the wind. Similarly Porcupine quills found next to a spoor that is difficult to identify, may not have belonged to that particular animal, but could have been lying there for some time.

Circumstantial signs

Circumstantial signs are any indirect signs in the immediate vicinity of a person or animal which may betray its presence. Such signs are usually seen in the behaviour of other animals. Birds may betray the presence of people to animals. Oxpeckers are most frequently found near large ungulates such as Buffalo, Eland and Kudu, upon which they clamber looking for ticks and blood-sucking flies. When approached, they will fly up and about, thus alarming the animals. Furthermore, animals may become restless. Baboons will move in short sprints and make a lot of noise. Antelope and Buffalo often stand and stare at intruders. Birds may also indicate the presence of snakes or dangerous animals such as Leopard or Lion.

Skeletal signs

Skeletal signs indicate the remains of animals and can be identified by the size and shape of the skull, the teeth and, if present, the horns. Skeletal signs may also provide feeding signs of carnivores.

Territorial signs

Territorial boundaries may be scent-marked with urine, faeces or scent transferred to bushes from special scent organs. Scent will usually not be perceptible to humans, but territorial signs may be visible in the form of latrines, pawing and horning of shrubbery. Some small antelope wipe their preorbital glands on the tips of grass or twigs, leaving a black tarry secretion.

Paths

Most animals have a network of paths or runs which they follow most of the time. Paths will always take the route that is easiest to follow, going round obstacles. Several animal species may sometimes use the same path or parts of it. They may also use man-made paths and roads, incorporating these into their own network. Paths are usually most distinct in the vicinity of good places and especially around waterholes. In the immediate vicinity of a waterhole, paths are most distinct as animal movement is concentrated towards it, forming a clearing around the waterhole itself. Further away from the waterhole paths become less distinct as they radiate outwards, branching off into smaller paths. In heavily wooded areas and forests, a network of paths is usually the only accessible route that animals can follow through the thick undergrowth.

Homes and shelters

Most animals continually move their sleeping quarters, and may only have a fixed home during the breeding season to protect the young. Some animals lack even this, the young being capable of leaving their birth-place soon after they are born, and continually shift the places where they sleep. Only a few animals have a permanent home which they use throughout the year. Homes are usually inconspicuous and in sheltered or inaccessible places so that they are difficult to find.

The most common homes found are birds' nests. They are usually well sheltered among the leaves of trees and bushes or in ground vegetation. Nests of different species are characterised by their position, size, structure and material used, and vary considerably in appearance.

Some small mammals build their homes in vegetation, which may look very much like birds' nests. Squirrels build their dreys in trees, usually close to the trunk. They are spherical and externally consist of loosely plaited twigs lined with grass or leaves.

Animals which do not construct homes or shelters, and simply lie down to rest in a sheltered place, often leave a depression with distinct impressions of the animals limbs and body. Hares create distinctive forms in sheltered places in long grass or next to bushes.

Many animals make their homes in the ground, often with a system of burrows. Underground burrows may sometimes be revealed by heaps of excavated soil. A number of creatures, such as Antbears, play an important ecological role in that their disused holes are often used by other animals for shelter. The occupant of a burrow may be identified if one looks at the size of the entrance hole, its position, and the method used to remove excavated soil, as well as tracks and droppings in front of and inside the entrance.