Wildlife Forensics -Pugmark Examination

Question: What is a pugmark?

Answer: The imprints or impressions left behind by the paws of animals. In simple terms, the footprints of animals can be called as pugmarks.

Question: Why are pugmarks important in wildlife forensics?

Answer: Wild animals are difficult to notice since they seldom come in contact with humans but their presence can be determined by the pugmarks which are found out on different surfaces like sand, mud, snow. Every animal species have its own pugmark, which has a variety of characteristics that may be used to assist in an animal’s identification. Pugmarks can be used as an indirect evidence to link the presence of an animal to the crime scene. Wildlife forensic experts use pugmarks to approximate class characteristics like sex, age and individual characteristics like deformities. It also helps in determining the gait patterns (movement). Pugmarks are widely used in cases of hunting, poaching, animal attack etc.

Question: What are the two types of pugmark impressions obtained?

Answer: 3-D Pugmarks- The impressions left behind on soft and irregular surfaces like mud, sand, snow, wet soil that create sunken imprints. These impressions will have length, breadth and height.

2-D Pugmarks- The impressions left behind on hard and smooth surfaces which are caused due to the deposition of materials like dust, blood will create surface imprints. These impressions will only have length and breadth.

Pugmarks can also be produced by lifting the dust or liquid materials off the surface, leaving a negative impression on the surface.

Question: Which animals are mainly tracked with pugmarks?

Answer: The large carnivores that belong to the Canidae and Felidae family are mainly tracked using pugmarks. Canidae is a family of dog-like carnivorans which hunt and roam as packs, frequently going great miles in a single file. On the other hand, Felidae is a family of cat-like carnivorans which live a solitary existence. The members of cat family (Canids) are excellent climbers. These carnivores typically leave a four-toed pugmarks with a heel pad.

Examples:

Canidae family- Dogs, Wolves, coyotes, foxes, jackals

Felidae family- Cat, Lion, Leopard, Tiger

Question: What are the differences between the pugmarks of canids and felids?

Answer: Canids– Claw markings are evident in front of the toe pads, the toes are bigger than the heel pad (to aid in running down prey), and the space between the two middle toes and the top of the heel pad is greater.

-While-

Felids– Claws or nails are rarely seen, the soft heel pad is bigger (to aid stealth), and the middle toes are positioned closer to the pad. The middle toes, especially on the hind paws, are at different levels.

Question: Which animal is an exception with respect to their pugmarks?

Answer: Hyenas can be regarded as a part of Canidae family but due to their exceptional characteristics, they are grouped to another family of their own known as Hyaenidae. The pugmark of a hyaena is clumped together with very little space between the pads.

Question: How do the pugmarks of few other animals look like?

Answer: Sloth Bear- Due to the existence of a flat sole in their limbs, the pug markings seem flat.

Fox- The pug markings quite near to the median line, giving the impression of rope walking.

Elephants- The huge size of pugmarks by itself reveals the identity of them.

Question: How to identify whether the pugmark is of the front or hind paw?

Answer: Front pugmarks are larger in size than the hind pugmarks. The other notable factor is that the forward most point of the two middle toes are almost at the same level in the front paw whereas the forward most points of the two middle toes are visibly apart in the hind paw.

Question: How to measure a pugmark?

Answer: The distance between the tip of the furthest toe and the base of the pad along the walking line is the Pugmark length (PML).

The distance between the outside margins of the first and last toes is known as Pugmark Breadth (PMB).

Measurement of pugmarks are done by finding the PML and PMB of pugmarks. The PML and PMB are calculated by drawing a box with all corners at 90 degrees and touching the pugmark’s extreme ends.

Question: How to distinguish between the male and female pugmarks of a Tiger?

Answer: A tiger’s paw has four toes and a pad. Only the front limbs have a fifth toe, which is known as the dew claw. Pugs in the front are bigger than those in the back. At the back end of the pad, there are three lobes. Male Pugmarks are bigger in size and more spacious between the toes than the female pugmarks. The PMB of the front pug is usually greater than its PML while in female tiger pugmarks, the PMB of the front pug is usually smaller than the PML.

The pugmarks of male tigers readily fits into a square while it fits into a rectangle in the case of females. The toe shape is elongated in the case of female pugmarks whereas it is rounded in males.

The difference between the PML and PMB is lesser than 1.5 cm in male pugmarks while it is greater than 1.5 cm in females.

Question: How to distinguish between pugmarks of tiger cubs from adults?

Answer:

  • The tracks of the adult Tigress will almost always be found next to those of her cub. Tiger cubs of that age do not have the ability to move on their own.
  • Adults have pug impressions which are compact. Their toes and pad are held together whereas a tiger cub’s pugmark is more spread out than an adult’s. The toes and the pad are held looser.
  • When compared to a tiger cub, an adult’s toe prints are smaller and narrower.
  • An adult’s stride is around 13 to 14 times its PML while a tiger cub’s stride is almost ten times its PML.

Question: Where to search for pugmarks?

Answer:

  • Dusty or wet grounds
  • Beds of rivers and streams
  • Near water holes
  • Roads and forest animal trails

Question: How to determine the walk sequence?

Answer:

  • If the hind pugmark falls ahead of the front then the speed of the animal was fast or hurried.
  • If the hind pugmark behind the front then the speed of the animal is slow and in a steady pace.

Question: How are the measurement of stride carried out using pugmarks?

Answer: Stride measures aid in the identification of tigers with pugmarks of comparable size. The length of a tiger’s stride can assist identify tiger cub pugmarks from adult leopard pugmarks.

STEPS TO MEASURE

  1. A walk sequence with the tiger moving at regular pace must be chosen.
  2. For measures, two consecutive hind pugmarks should be chosen.
  3. Measure the distance between the hind left and the next hind left, or the hind right and the next hind right.
  4. The measuring tape’s zero end should be held at the front tip of the first pugmark’s pad and stretched to the second pugmark’s pad tip.
  5. Measure the distance in centimetres and the distance between the left and right pugmarks determines the step length.
Image Source: Guidelines for estimating wild tiger populations using the Pugmark Technique By Dr L.A.K. SINGH

Question: What is the manual method of collecting pugmarks?

Answer: Pug impression pads (PIP) are used for manual collection of pugmarks. PIP is a patch of dusty dirt that was made by hand in order to acquire good pug impressions. These are positioned along paths where tigers and leopards are likely to go. A PIP site should be chosen in such a way that the animal finds it difficult to ignore or circumvent it. It should be completed well ahead of the enumeration. Animals are occasionally apprehensive about treading on freshly made PIPs. The soil used for preparing PIP should be preferably from the surrounding areas.

Question: What are the other methods of collection?

Answer:

Tiger pugmark tracer- This is used when the pugmark cannot be lifted from the surface. A tracer is kept in close distance to a pugmark and the outline of pad and toes are traced onto the glass surface of the tracer.

Plaster cast- These are used to collect the 3-D impressions of pugmarks. Water is added to a cup and an equal ratio of POP (Plaster of Paris) is also added. This mixture is stirred to make a semi-liquid form. The pugmark is then encircled using an aluminium strip or paper. Then the mixture is gently put on the surface containing the imprint. Once, the POP hardens, the impression is collected for future investigations.

Question: What are the important information to be written on the collected pugmark?

Answer: Before the plaster cast dries up fully, put the following information on a thin stick that will be needed for the analysis:

  1. Unit name
  2. Unit number
  3. Date of collection
  4. Place of collection
  5. Time of collection
  6. Reference number for tracing
  7. The initials of the individual who collected the print

This is done to make sure that the chain of custody is followed during all the steps of investigation.

IMPORTANT INFORMATION

  • Pugmarks with a PML of less than 6 cm are most often from lesser cats.
  • Pugmarks with a diameter of 5 to 7 cm might represent leopard cubs.
  • Pugmarks with a length of 7 to 9.5 cm may belong to adult leopards.
  • Tiger cubs might have left pugmarks with PML ranging from 7 to 10 cm.
  • PMLs ranging from 9 to 17 cm indicate mature tigers.
  • Digital pugmark technology (DPT) is a new method of identifying animals using their pugmarks. Using a statistical technique, this method is utilised to estimate the specific individual species. While walking, each animal leaves its own set of pugmarks.

Question: Why are pugmarks important?

Answer: The information contained in the pugmarks may be easily documented by traces and plaster casts for examination at a higher level with some basic training and an honest attitude. Pugmarks, when properly and honestly analysed, can give trustworthy data on:

  1. The presence of several species in the area of study.
  2. Determine population of large cats.
  3. Individual identification of big cats, as well as their sex ratio. The higher the skill level, the higher the accuracy.
  4. To determine animal gait patterns- Depending on their body mechanics and behaviour, various animals move in different ways. Deer and cats, for example, spend the majority of their time walking. Other animals, such as coyotes and foxes, are designed to trot. Several additional animal species have distinct hopping, loping, or bounding movement patterns that are unique to them. These movement patterns will hence help in identifying the animal.

CASE STUDY

From November 27, 2019, until the first week of January, a leopard assaulted and murdered six people in Bhogpur village, Bijnor district. In other locations, the leopard’s pug markings could be seen. These pugmarks were discovered in Mandawar and matched with others. The leopard was later slain by locals on January 6, 2020, after it attacked and murdered a schoolboy in Bhogpur village. According to forest officials, the killer leopard was identified by utilising video traps and comparing its image and pugmark to that of the deceased leopard. Both matched, showing that the leopard the forest department was attempting to catch was the same one.

Sources & References
  1. Dhande, R., & Gulhane, P. V. (2016). “ Implementation Of Identifying Tigers Through Their Pugmark On Android Phone Application .” 2432–2436.
  • Sharma, S., Jhala, Y., & Sawarkar, V. B. (2003). Gender discrimination of tigers by using their pugmarks. Wildlife Society Bulletin, 31(1), 258–264. https://doi.org/10.2307/3784382
  • Singh, L. A. K. (1999). Guidelines for estimating wild tiger populations using the Pugmark Technique. WWF Tiger Conservation Programme, India, December, 1–40.
  • Talwar, R., & Usmani, A. (2005). Reading pugmark. WWF-India, 1–56.

Authored By:

    

Akhila Prabhakar

       B.Sc. (Forensic Science)

Jain (Deemed-to-be University)