Tiger Genomics in Captivity

Understanding genomics is lynchpin to tiger conservation. With wild tiger populations in danger worldwide, consolidating methods to understand tiger genetic movement, variance between populations, and specificity of genes is imperative.

Without genomic data, conservation strategies from reintroduction to specific subspecies preservation are far less effective. Gaps in data, funding, and regulatory environments, however, have complicated efforts to effectively maintain and utilize conservation methods across the board.

Outside of India, there are conservation efforts being implemented in multiple countries, however, the research remains limited. Authors from the U.S. and the U.K. stand behind India in terms of publications released, with a focus on captive populations and illegal trade. Most of the research done on captive tigers between 2010 and 2022 were done in the U.S. In terms of research done on genetics, most research centered on species and individual identification specifically (Maharjan et al. 2024). Research such as this paves the way for understanding genetic variation, variability, the impacts of inbreeding and founding events, demographic history, and signatures of local adaptation. Understanding this information would be crucial to know what the genetic consequences of inbreeding are, and to how this research could be improved.  

Beginning from American tiger showcasing in the early 1800s, over 10,000 tigers exist in the United States today. Legal for private ownership in 30 states, tigers are distributed across zoos, sanctuaries, and private hands alike. Conservation efforts have led to some federal and state regulations have aimed to balance the welfare of tigers: The Endangered Species Act and other wildlife protection laws are key examples. Some challenges that tiger face outside of captivity include habitat loss, poaching, and human-wildlife conflict. The key subspecies held largely reflect those still existent in the wild: the Amur, Bengal, Indochinese, Malayan, South China, and Sumatran tigers. Recently, captive tigers have become pop-cultural phenomenon, especially from shows like Tiger King and greater societal exposure. The existence of such populations represents several important conservational opportunities. Unfortunately, much of their current utilization is far from altruistic.

From 2011-2024, a total of 362 tigers were rescued through Tigers in America. The tigers were mainly found in failed sanctuaries, roadside zoos, with breeders, or private owners and have been sent to proper sanctuaries all throughout the U.S. These rescues account for a very small number of the number of captive tigers estimated to be in the U.S. Despite the efforts of organizations like Tigers in America, many tigers still remain in inadequate or improper conditions. The ongoing challenge of addressing the welfare of captive tigers underscores the importance of continued advocacy, education, and support for initiatives aimed at protecting this species.

With an unclear picture of the ownership, locations, and treatment of American tigers, equally unclear are the factors influencing their breeding, genetic movement, and the like. Without clearer regulations and a more concerted view on treatment and research, the opportunities American tiger populations represent for conservation risk fading away.

The importance of strong genetic tools for tiger conservation is essential to the end of current American tiger treatment. An emphasis on the global benefits America's tiger population could have, if utilized in a focused and humane manner, is critical to improving regulations and attitudes. Some examples include using advanced genetic tools for conservationists to assess and manage the genetic diversity to prevent inbreeding and maintain long-term population viability. Genetic research can also help with fighting wildlife trafficking, by identifying places of origins. By focusing efforts on genetic research, we can further improve regulations and management practices to improve the long-term survival of tigers not only in the United States but also all around the world.

Tigers in America, a nonprofit organization founded in 2011, is a leading advocate in the rescue and relocating of captive tigers in the United States. They are committed to helping provide sanctuary and rehabilitation for mistreated tigers in captivity. Since 2017, Tigers in America has become a pioneer in captive tiger genetic research. By leading initiatives focused on using genetic tools and analyses for conservation purposes. They aim to inform the challenges facing captive tiger populations like genetic diversity, health management, and fighting illegal tiger trade. Genetic research can help lead the way to positive changes in tiger conservation.

Armstrong et al., published in 2024, was the largest genomic study that looked at the private captive tiger population labeled ‘Generic,’ in the United States. This comprehensive genetic analysis of the tiger population revealed that the genetic diversity in the ‘generic’ tiger population was very similar to wild tiger subspecies. Many genetic components of ‘generic’ tiger populations saw parts from all six extant wild tiger subspecies. The study found that the generic population contained less deleterious recessive homozygous variation. Although there were some instances of inbreeding, the genetic health of the ‘generic’ tiger population saw very few deleterious mutations. This study can be used as a reference to incorporate genetics by displaying a more modern way to accurately enable individual identification with minimal data. The findings in the study, relating to the genetic diversity and history of ‘generic’ tiger population, can work as a resource to support tiger conservation!

1. Armstrong, E. E., Mooney, J. A., Solari, K. A., Kim, B. Y., Barsh, G. S., Grant, V. B., Greenbaum, G., Kaelin, C. B., Panchenko, K., Pickrell, J. K., Rosenberg, N., Ryder, O. A., Yokoyama, T., Ramakrishnan, U., Petrov, D. A., & Hadly, E. A. (2023). Unraveling the Genomic Diversity and Admixture History of Captive Tigers in the United States. https://doi.org/10.1101/2023.06.19.545608
2. Episode 6: The trouble with america’s captive tigers. Podcasts. (2020, December 1). https://www.nationalgeographic.com/podcasts/overheard/article/episode-6-trouble-america-captive-tigers-overheard
3. Henry , L. (2020a, March 31). 5 things tiger king doesn’t explain about Captive Tigers | stories | WWF. https://www.worldwildlife.org/stories/5-things-tiger-king-doesn-t-explain-about-captive-tigers  
4. Liu, Y.-C., Sun, X., Driscoll, C., Miquelle, D. G., Xu, X., Martelli, P., Uphyrkina, O., Smith, J. L. D., O’Brien, S. J., & Luo, S.-J. (2018). Genome-wide evolutionary analysis of natural history and adaptation in the world’s Tigers. Current Biology, 28(23). https://doi.org/10.1016/j.cub.2018.09.019 
5. Maharjan, A., Maraseni, T., Allen, B.L. et al. A systematic literature review: Trends and current state of research on Bengal tiger (Panthera tigris tigris), 2010–2022. Biodivers Conserv (2024). https://doi.org/10.1007/s10531-024-02856-3
6. Tigers across the world. NCBS News. (2015, January 22). https://news.ncbs.res.in/research/tigers-across-world