Research Article : Hiby, L., Lovell, P., Patil, N., Kumar, N. S., Gopalaswamy, A. M., & Karanth, K. U. (2009). A tiger cannot change its stripes: using a three-dimensional model to match images of living tigers and tiger skins. Biology letters, 5(3), 383-386. DOI: https://doi.org/10.1098/rsbl.2009.0028

Key Takeaways: 

  • Illegal poaching and trafficking of wild animals and their products have been a serious problem in conservation for decades. 
  • A team of scientists developed a three-dimensional model to identify the individual tigers more confidently in a time efficient manner, and identified close to 300 individual tigers from Bandipur and Nagarhole tiger reserves. 
  • Using this software, tiger skins of even individuals killed years ago, can be traced back to its origin. This has immense conservation and management implications. 

 

The illicit trade in wildlife and animal products has remained a serious concern in the field of conservation for decades, posing a direct threat to the survival of endangered species. Among these, charismatic species like tigers face an even greater threat due to persistent poaching for their valuable skin and body parts. While India has  strict anti-poaching laws, these regulations work best when poachers are apprehended. This raises important questions about unsolved cases of tiger poaching, where law enforcement is unable to catch the criminals, and the source of the tiger skin remains unknown. It is crucial to get this information for developing effective conservation and management strategies for tigers. 

In response to these serious challenges in tiger conservation, in 2009, Dr. Ullas Karanth and Dr. Lex Hiby, and their team, created a software capable of identifying individual tigers based on their distinctive stripe patterns. What sets this model apart is its ability to analyze skin images, even in cases where the animal was killed years ago, and match it with prior images or camera trap photos of the same tiger. This information is invaluable for management and conservation. Knowing the origin of a particular tiger skin can pinpoint areas requiring intensified conservation and security efforts and illuminate the intricate supply chain responsible for trafficking these skins.

Since the 1990s, Dr. Ullas Karanth and his team have consistently monitored tigers in the Bandipur and Nagarahole National parks and tiger reserves using camera traps. Over the years, their studies have led to the identification of nearly 300 individual tigers based on their unique stripe patterns. This work was primarily conducted through manual comparisons, involving visual assessments of each new image against an extensive database. However, this method is only practical for regions with relatively small tiger populations. In areas with larger numbers of individuals, manually comparing images with the database becomes a time-consuming and arduous task, taking hours, if not days, to complete.

To address this challenge, the researchers devised a three-dimensional surface model for tigers. This model enables a camera trap image of a living tiger to be matched with an image of its skin laid out on a flat surface. By utilizing camera trap images from Bandipur and Nagarahole, this research demonstrates a substantial time and effort-saving approach for individual tiger identification. It also highlights its potential for use by wildlife crime and forensic personnel in their critical efforts to combat poaching and wildlife trafficking. Moreover, the authors even propose creating a central database for all camera trap images. Through this method, the  skin of an individual tiger in the database can be matched within a few minutes, to precisely determine when and where that particular individual was last recorded alive. 

 

Key Words: Tiger stripes, illegal trade, individual identification, conservation

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