Importance of  Digital Pugmark Technique & Pugmarks in Wildlife Forensics

Importance of  Digital Pugmark Technique & Pugmarks in Wildlife Forensics

Pugmarks are footprints or paw print of animals. Pugmarks are unique to every animal like fingerprints and are widely used as a diagnostic tool for the identification of the specific animal. Every animal leaves its unique paw prints when they move from one place to another. Different studies suggests the use of pugmarks in censing and monitoring the wild animals. Pugmarks can be used as very useful identification tool in wildlife forensic to monitor the wild animals in forest and in poaching cases to identify the location of animal or from it was poached.

Wild animals can be difficult to spot because of their instinctive behaviour to avoid humans. However, the presence of wild animals often can be determined by their pugmarks in snow, sand, or soft mud. Whenever an animal moves through the jungle over a suitable ground, leaves mark or impressions it called as pugmarks (paw marks). In simple terms, pugmarks refer to the footprints of almost all the animals. Every individual animal species have distinct pugmarks and numerous features contained in it can be used to support the identification of an animal.  Many people have learned to read wildlife pugmarks with a remarkable skill for hunting purposes.

In wildlife forensic, pug marks have significant importance and considered as valuable evidence. These pugmarks are easy to discover indirect evidence of an animal presence. The keen observation of these pugmarks can tell a lot about the animal’s sex, age, size, health conditions, and the time and direction in which the animal had moved. The scientific examination, identification, and comparison of pug marks from crime scenes can link with a suspect and a victim.

Digital Pugmark Technique

Traditionally tiger censuses in India have been carried out by collecting plaster-of-Paris casts and hand tracings of pugmarks (usually of a tiger’s left hind foot) found in an area during a specified time. These are then analysed, along with movement and other data, to deduce the tiger population. However, this method has long been criticised by scientists and conservationists for being too subjective and open to error. The Digital Pugmark technique is also based on the theory that each tiger leaves a distinctive set of pugmarks. The difference is that the use of the software PUGMARK 1.0 eliminates human error. Digital photographs of a series of pugmarks and stride and straddle measurements, where a tiger has walked in a normal gait, and a GPS location, are taken from a single pugmark trail. This data is then entered into a computer which calculates the values of several variables from the photographs. Statistical analysis of the data creates a ‘profile’ of the tiger, which can be used to identify it from other pugmarks. Twelve predictor variables are used to accurately identify individual tigers from their pugmark impressions. It is important to note that an entire pugmark set (a series of continuous pugmarks made by the same tiger) provides the identity of a tiger, i.e. the accuracy depends on data from a set of pugmarks, and not an individual pugmark. PUGMARK 1.0 was designed and programmed by Sandeep Sharma in 2002, while he was a student at the Wildlife Institute of India. The design of the software also formed a part of Sharma’s Advanced Diploma in Information Technology at the Centre for Development of Advanced Computing, Pune. The software was further developed with support from the Wildlife Protection Society of India. The software PUGMARK 1.0 was developed using Visual Basic 6.0. It can be used for pugmark image analysis and pugmark database management. The software is equipped with selfexplanatory GUI (Graphical User Interface) to make it user-friendly.

Pugmark technology, Camera trapping and Digital pugmark technology (DPT) is the latest methods based on the distinctive set of pugmarks……

Pugmark signifies identity. Pugmark plays a major role in identifying a given specific animal in terms of sex, age or size as well as total accuracy of the given individual species. Pugmark denotes “paw print” of most feline animals. Herbivore foot prints are called as hoofmark (Deer, Antelope) or simply foot print (Elephant). Every specific individual has its own distinct pugmark and as such, this is used for identification purposes.

The best example is the tiger census programme which is completely based on pugmark technology. The method is simple and easy to count the animal in a very special manner, sometimes bias may happens. Camera trapping, Scat analysis or GIS application are the new advance formula for getting total occupancy in a given forest environment. Similarly, pug-mark is also helpful in tracking those animals that are stray away from the boundary areas, conflicting with the human environment or create problems of their own because of injury.

With the advancement of new technological tools and skills, it is easy to deplete a forest and make possible for declining the animal presence in the surrounding ecosystem services, and with the continued process, leads the decline of prey base in the forest areas, the wild animals are moving towards nearby areas resulting in Man- Animal conflict.

Larger feline never exists in this particular type of national park nor in the adjoining areas is true, the animal might be walking from some area in search of easy prey or the habitation has been invaded by some foreign invasion. Likewise, it also indicates that the stray feline found the habitat better, as most of the forest blanket’s are comes under biotic pressure and with the result; they find their own route away from human habitation.

The unsolved puzzle must be solved only after getting the animal from the surrounding adjoining areas and it’s now an important task for the forest people to find the animal in the best possible way before the feline take shelter in the nearby bushy for another prey.

Large terrestrial feline (Tiger, Leopard) share the same forest environment but they never share their territorial boundary. The former one is directly depends, either on smaller herbivore (Wild boar, Barking deer, Peacock) or larger one (Sambar, Spotted deer, Nilgai) while the latter is mostly depend on small animals (Wild boar, Domestic dog, Calf).

Tiger is marked as extinct species from the land of Manipur and chances of sighting is very poor. If possible, Tiger pugmark are easy to identified as their paw are soft enough and difficult to walk on thorny/ bushy areas, as a result, their pugmarks are clearly seen near fine level roads, trails or near the river beds/stream or lake. Tiger sex can be easily identified from the following figure:

Adult male tiger pugmark (MTP) forms a square while female tiger pugmark (FTP) fits into a rectangle shape. Toes in male are rounded whereas it is fairly elongated in female society. Female pugmark length and breadth is 1.5 cm more than male tiger pugmark. The interesting fact is, tiger cub pugmark (TCP) is much similar with the leopard or wild dogs’ pugmark. The difference in wild dogs is summed up as non visible claws; toes are smaller and larger pads in tiger (visible claws, toes larger and pads smaller in dogs).

Leopard are versatile feline which is not selective about its habitat, its exists on the periphery of the forest areas and is prone to venturing into human habitats and leads to direct conflict with the humans. Studies done by organizations like specialist group of IUCN (International union for conservation of nature and natural resources) in certain parts of India indicate an increase in leopard human conflict. Though leopard are protected under Schedule 1 of the Wildlife Protection Act (1972), they face severest backlast from humans and grave threat from poachers.

Leopard is also more visible than tigers. Linear factor is the common methods for identifying the leopard pugmarks. The work is done directly in the field by using digital caliper to record the track length, track width, track pad width, pad length, pad curve, stride size etc. Different age groups (Cub, Sub adult, Adult) can be classified on the basis of distinct differences in the relative length of track length, track width, pad width, pad length etc.

It is also possible to identified species from the scat ( leopard scat is much larger than tiger, less coiled having a larger distance and diameter between two successive constrictions within a single scat, John Singh, 1983., Ramesh, 2010). For simple verification, Leopard pads are smaller, narrow toes and small in size as compare to tigers.

Digital pugmark technology (DPT) is another new terminology based on the theory of pugmark technology. The method is used for estimating the specific individual species using statistical approach. Each animal leaves a particular set of pugmark while walking.

For analysis, the pugmark is clearly photographed in a serial way, GPS (Global Positioning System) location are taken from the first sight, stride and straddle measurements, where an animal walked in a normal gait. Stride is the distance between two successive pugmarks on the same side while straddle is the perpendicular distance between the left and right hind pugmarks. The data is then calculated with the help of software “pugmark 1.0” which totally eliminates human error.

The data calculates the values of several variables from the photographs. Statistical analysis of the data creates a new profile of the animal, which can be used to identify it from the pugmarks (The technology is already applied in tiger calculation work, not applicable for high rainfall environment).

For best result, Pugmark Impression Pads (PIPs) were made where animal frequently walks (roads, trails), for getting the clear mark of pugmarks. PIPs consists of an area approximately 6m long and as wide as the road ( nearly 2.5 m) where the soil is finely pulverized to an optimal soil depth of 0.5- 1 cm in order to provide the best possible surface for recording pugmark impressions.

Nature of pug marks:-

Pugmarks are produced under the following circumstance:

1. The impressions of the pug may be caused in mud, dust, sand, and snow or similar surfaces. These impressions will be depressed or three-dimensional type and these are known as sunken pug mark impressions. These type of pug marks are most commonly found.
2. If the pug mark is produced by deposition of material like dust, dirt, blood, colored powdery substance, etc., on hard and smooth surfaces, giving rise to a two-dimensional print, which is called surface pug mark.
3. Pugmarks may also be produced by lifting dust or liquid material in which case a negative print will be left on the surface.

The different species of animals, especially the large carnivores that are traditionally tracked with the help of pugmarks are divided into two broad categories:

1. The members of the ‘Dog family’ or the ‘Canidae’ that typically move and hunt in packs often walking long distances in a file. In the members of this family, the claw marks are usually noticeable in front of the toe pads. As compared to the heel pad the toes are larger which helps them to run down the prey and the gap between the top of the heel pad and the two middle toes is evidently more than what is found in cats (hyenas is an exception). The front points of the two middle toes occur side by side (aligned).
2. The members of the ‘Cat family’ or the ‘Felids’ that lead a solitary existence, depending on stealth for hunting down prey. They are acceptable climbers and some like the leopards take their hunt to a tree for abstaining from poaching by different carnivores. The claws or nails are hardly ever visible, the soft heel pad is comparatively larger (to encourage stealth) and the middle toes are put nearer to the pad. The middle toes of the felids are at different levels, especially for the hind paws.

Mostly the large carnivores leave the soft padded four-toed pugmarks in the jungle.

Pugmarks of Sloth Bear, Elephant, Fox & Tiger:-

• In the case of sloth bear tracks, the pug marks appear flat due to the presence of flat sole in their limbs.
• In the case of elephants, the size of the pugmark itself reveals the elephant’s footmarks.
• In fox, the pug marks are very close to the median line, creating an impression of rope walking.
• In tiger’s, pugmarks comprise of a pad and four-toes. A fifth toe is commonly called the dewclaw, which is put high on the front limbs only and it does not contact the ground. At the rear end, the pad is 3-lobed.

Significance of Pug Marks:-

Pugmarks of wildlife species are important evidence in the forensic analysis of species. The significance of pugmarks is discussed below.

(1)  Determination of Sex using Pug mark Measurements:

The sex of animal species can be determined by measuring the length and width of full pug mark, pad, and toe and some other distinct features. Example, Tiger- The pugmarks of mature males are usually larger than that of the females. The pugmarks of a male nearly fit into a square whereas the pugmarks of a female nearly fit into a rectangle. The shape of toes in a male is more rounded while in the case of females they are elongated.

(2)  The age of Pugmarks can be calculated by looking at the dust and soil depositions. When pugmarks are fresh, then the wall of the soil, sand, or dust surrounding the imprints of toes and pads are intact and almost perpendicular, and the bases of imprints of pugmarks are smooth flat. With time, depending on whether pugmarks were in a shelter or an open spots, the actions of the rays of sunlight, the rate of airflow, the dewdrops of the night, the dust deposited on the pugmarks and the movement of invertebrates, the walls of the pugmarks get cracks and the pile of earth that took the weight of the animal also begins to fill up with dust deposits and other droppings.

(3)  Animal Movement Patterns (Gaits):

Different animals move differently depending on their body mechanics and behaviour. A few animals like deer and cats spend the majority of their time walking. Other animals like coyotes and foxes are intended for trotting. Numerous other animal species have their particular hopping, loping, or bounding movement patterns that are unique to that one specific animal species. These gait patterns are a major key for how trackers interpret the behaviour and even foresee future activity of animals just by contemplating trail patterns. Notwithstanding, these will also help you more strongly to recognize what animal made the trail.

(4) Identification of Animal Species based on Pugmark Analysis:

“Every individual animal has its distinct pugmark.”

This principle is used for identification purposes. Pugmark plays a major role in identifying a given specific animal in terms of sex, age, or size as well as the total accuracy of the given individual species. Humans have difficulty in carrying out this task because not every footprint left by the animal is the perfect one. The abnormalities or deformities in a particular paw become relevant and hence, it narrows downs the search. In the manual method of identification, a series of measurements of pugmarks are noted and compared with the available data.

Digital pugmark technology (DPT) is a new age technology for the identification of animals based on their pugmarks. This method is used for estimating the specific individual species using a statistical approach. Each animal leaves a particular set of pugmarks while walking.

(5)  Study of Wildlife Population (Census) / Pugmark-based population monitoring:

The population of the remaining rare animals in the forests needs to be protected. An animal footprint is the unique identity of the animal world. There are several techniques available to study animal behaviour. This method is a safe and brilliant way to spot the presence of an animal in a place. The main objective of the wildlife census is to find out the density of the population of the species and to procure basic data for its management.

(6) The pugmark is also helpful in estimating time when an animal moved and direction in which the animal traveled. The major problem with pugmark impressions based on the identification of species includes is an undetectable footprint on hard surfaces and sometimes these footprint sites are often contaminated by the presence of other animals. Undetectable pugmarks and erosions by the other animals in pugmarks analysis are the major limitations in the field of wildlife forensic. If pugmarks analysed skilfully and lawfully, they can provide reliable data.

The wildlife animals are masters of disguise and therefore not easy for the humans to identify or spot them. But there can be some signs left behind that can help spot these animals. Pug marks are very helpful for the same. The marks that the animal leaves of his paws in the sand, mud, snow or any other impressionable surface are called as pug marks or in layman terms pug marks are the footprints of the animals. Like every human being has a distinct footprint likewise every animal has a distinct pug mark which can be used to identify the animal. The pug marks have different features and characteristics which help in such identification. The pug marks are important in order to find out various details about the animal whose pug marks are examined for instance:

Gender

The sex of the animal can be identified when measurement of the entire pug mark. Toes and pad are taken. The pug marks of a female are larger and more elongated than the male which are smaller and rounder.

Age

The age of Pug marks can be calculated by seeing that if the dust and soil depositions of the footprints are fresh. If they are fresh then the wall of the soil, sand, or dust surrounding the imprints of toes and pads are still together giving a clear impression of a paw mark. They are almost perpendicular to each other. The bases of imprints of pug marks are smooth flat. With time, depending on whether pug marks were in some covered area or in open ground, the movements and the actions of the rays of sunlight, the rate of airflow, the dewdrops of the night, the dust deposited on the pug marks and the movement of invertebrates, the walls of the pug marks get cracks and the pile of earth that took the weight of the animal also begins to fill up with dust deposits and other droppings.

Size

Every animal has its own movement and the way they walk which are in accordance with their body types and behaviours. For instance, animals like deer and cats spend the majority of their time walking or wandering places. Whereas, other animals like coyotes and foxes are intended for trotting. And nnumerous other animal species have their particular way of hopping, loping, or bounding styles which are very distinct and unique to that entire particular animal species. These gait patterns are a major key for how trackers interpret the behavior and even foresee future activity of animals just by contemplating trail patterns. Notwithstanding, these will also help you more strongly to recognize what animal made the trial.

• Direction where it was going.
• Time of such movement.
• To keep record of the count of animals around the country. There are various animal and other wildlife species that are undiscovered so these pug marks can be helpful to identify such animals. This test can also be done to know the presence of certain animal at certain place keeping the track of density of population of species to regulate the area accordingly.

Why the ‘Pugmark Census’ Used to Monitor Tiger Populations Failed

In 2003, some highly respected conservationists got together to write a paper for an international journal, in which they laid bare the loopholes in the pugmark method of counting tigers in India. Shortly thereafter, in an extraordinary sequence of events, newer and more advanced methods were used to assess the tiger population, which resulted in the shocking denouement that there were only about 1411 tigers in India. Read on to discover how the scientists rated the old ‘pugmark census’.

The ‘pugmark census’ was invented in 1966 by Indian forester SR Choudhury. In this method, during a 1–2-week period, thousands of personnel would simultaneously fan out across India to search for tiger tracks. They were expected to locate tiger tracks and obtain plaster casts or tracings of the left hind pugmark. The pugmarks collected would be later compared to identify individual tigers relying on perceived differences in shape and other measurements. These ‘individual tiger identifications’ would be then refined through cross-comparisons among census blocks, reserves and larger regions to obtain ‘reliable estimates’ of wild tiger numbers in India.

The census-takers were expected to locate the tracks and obtain plaster casts or tracings of the left hind paws of nearly all the tigers in the entire country. The pugmark method was questioned by scientists, who pointed out that the following assumptions must hold true for the pugmark method to be statistically valid:

1. The entire potential tiger habitat in India had to be effectively covered during the pugmark census.
2. All the four paw prints of every individual tiger in the surveyed area had to be detected during the censuses.
3. The same hind pugmark of each one of these individual tigers must be lifted from suitable and comparable substrates or from standardized soil track-plots.
4. The shape of each pugmark lifted had to be recorded without distortion by the thousands of census personnel involved in the operation.
5. Supervisory officials were expected to be subsequently able to segregate the pugmarks of each individual tiger correctly, based on footprint shape, track measurements, and prior local knowledge.

Failure of assumptions 1 and 2 would lead to under-counts; failure of assumptions 3 and 4 would lead to overcounts; and failure of assumption 5 could lead to either undercounts or overcounts.

Unsurprisingly, the ‘pugmark census’ could not live up to this scrutiny:

1. Surveying the entire area: In reality, only an unknown fraction of the 3,00,000 km2 that is considered habitable by tigers, is searched intensively during censuses. For example, logistical constraints (e.g. in Namdapha, Sundarban), security concerns (e.g. in Nagarjuna Sagar, Indravati and Manas reserves) or staff shortages (almost everywhere) restrict the proportion of the area covered by field teams.
2. Locating the tracks of every individual tiger: The probabilities of finding the tracks of each individual tiger in the surveyed area are low, except in a few reserves with high road density and suitable soil type.
3. Selecting the appropriate pugmark: Lifting pugmarks from firm soil overlaid with dust or sand is an essential precondition to obtaining accurate pugmarks. Unless clear impressions of all the four paws on the right soil are detected for each individual tiger, it is impossible to pick the same hind pugmark of each individual for comparisons, as prescribed by the pugmark method. In reality, census personnel often do not find clear prints of all four paws, and consequently lift prints of the different paws of the same animal from different localities.
4. Recording and recognizing tiger tracks: The shape of the same tiger footprint traced by different persons may vary considerably. This variation can be reduced by using well-trained persons in controlled trials, but not in field censuses involving thousands of personnel with varying levels of skills.

Three decades of tiger monitoring following this unrealistic method essentially failed in India—despite being backed by massive investments and the best of intentions. This failure has, inevitably, led to poor conservation practices. For example, field managers initially reported an increase in tiger population in 1994, despite mounting evidence of deteriorating reserve protection and increasing poaching pressure.

Possible alternative approaches to monitoring tigers at different levels of resolution

In areas that are fragmented or degraded: It is critical to document annually the presence or absence of tigers in such areas. The present large-scale, labour-intensive pugmark censuses can be modified into surveys of tiger-sign — this involves merely recording the presence of tiger tracks and other signs under a rigorous sampling design. Such surveys will not involve the impossible task of individually trying to identify all wild tigers from track prints under field conditions. Positive results from such surveys could enable restoration and reconnection of fragmented habitats, establishing new or larger populations.

In individual reserves: Managers need to keep track of tiger populations to evaluate the effectiveness of conservation schemes. Even under resource constraints, densities of tigers can be derived annually using encounter rates of tiger-sign (e.g. number of tiger track sets or scats encountered per 10 km walked, the proportion of 1 km trail segments in which tiger tracks were detected, number of fresh tiger tracks crossing the path of a boat or vehicle). This will, however, not translate into accurate predictions of tiger populations.

At priority sites: In some areas, absolute densities of prey and tigers may need to be estimated. In such cases, there is no escape from employing advanced equipment and techniques, and skilled personnel. Such techniques will include line transect surveys of prey densities and camera-trap capture–recapture surveys of tigers.

Conclusion

The ecology and nature of any country is not less than any treasure and India is blessed with such diverse flora and fauna. In past few years because of the era of industrialization and modernization the loss of forest areas and therefore decreasing number of wildlife species has become a common trend. But in order to stop all this and preserve the wildlife various legislation and regulations are made. It is the duty of the state and every individual to take care of his natural environment. The Wild Life (Protection) Act, 1972 serves the purpose of protecting, preserving the wildlife population of the country with different boards, authorities to punish those who violate these laws. The main objective of the Act is to achieve a safe and improved environment for animal kingdom of the country.

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Compiled  & Shared by- This paper is a compilation of groupwork provided by the Team, LITD (Livestock Institute of Training & Development)

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