Farewell Tsetsen, A Snow Leopard’s Legacy

Almost a decade after we first met Tsetsen, we are saying goodbye to this intrepid cat. His legacy will continue to shape our conservation efforts and the stories we tell about this iconic species.

Tsetsen (M11) first wandered in front of one of our camera traps – and into our long-term ecological study – in 2013. Since then, he was fitted with a GPS collar programmed to fall off within two years which allowed our researchers to track his movements across the Tost Tosonbumba Nature Reserve in Mongolia. And wander he did – about 176 miles in just a two-month period – climbing up and down more than 7000 meters in the western reaches of this protected area.

Photo courtesy of Lkhagvasumberel Tumursukh
Photo courtesy of Lkhagvasumberel Tumursukh

After closely examining our camera trap data for the 2022 survey year, we noticed that Tsetsen, who usually makes many appearances, was not observed in the area for the first time in nine years. Our researchers also found that Tsetsen’s large home range has been taken over by an unnamed male born in 2019 to Dagina. We have observed this before, where a younger counterpart either displaces an older male or moves to occupy a vacant home range. 

Tsetsen has always had a penchant for wandering, so one possible conclusion is that he has left Tost after being pushed out of his home range. Another possibility is that he has passed on. We estimate Tsetsen would be about 12 years old now (that’s getting up there in the tumultuous and unpredictable wild.) and the second-oldest male snow leopard ever monitored in Tost. Whether he has passed on or moved elsewhere, his legacy has helped guide our understanding of this majestic and elusive species.

Tsetsen was the 20th cat and 11th male to be part of our long-term ecological study. We often share more insights about female snow leopards – partly because we knew so little about their reproductive rate and success for so long. But the males in our study have contributed to our knowledge as well.

Tsetsen’s initial movements were very revealing, not just because of the length of his journeys or the immense elevations he traversed. His movements intrigued researchers because they so neatly overlapped with another male cat that inhabited his range. 

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When Tsetsen established his home range in the west of Tost, the area was vacant after the previous owner Ariun, who we had tracked since 2012, had passed not long before. Tstesen used his large area (5x the size of Manhattan) almost in lock-footstep with his predecessor, navigating the cliffs and crags in the same predictable and repetitive patterns. The first male we collared in the area, Shonhor, also used exactly the same range. This suggests that topography and other natural barriers likely play an outsized role in how snow leopards establish their home ranges.

Because we saw the young male many times in the 2022 survey throughout this area and did not see Tsetsen at all, it seems that this pattern may be repeated. While we have not tracked this young male’s movements yet – it will be interesting to see if he follows in Tsetsen’s (and Shonkhor and Ariun’s) “paw”-steps. This also establishes a cross-generational connection between male cats that is otherwise challenging to pin down, as it is difficult to track the lineages of male cats the way we do with females. So while we know that at least two females have overlapped with Tsetsen’s territory for many years, we cannot ascertain if he is the father of any of their cubs. This is an area where DNA analysis could provide valuable insights, and our team hopes to explore these scientific questions in the future. 

It’s never easy to say goodbye, but we are thankful that Tsetsen wandered into our lives almost a decade ago. The primary purpose of our long-term ecological study in Tost is to learn more about snow leopard ecology to better inform our conservation efforts. We know that, at times, the scientific lens can feel impersonal and detached. That is one reason we work with our team in Mongolia to invite Mongolian conservationists, our researchers and our supporters to name snow leopards that become part of our study. When we name a cat, it helps establish a deeper connection to an elusive species many of us will never see in the wild. Though he didn’t know it, Tsetsen contributed invaluable insights and data to snow leopard conservation. We hope the life of this incredible cat has inspired you as much as he inspired us.

You can honor Tsetsen’s legacy and help track the wanderings of cats for generations to come with a symbolic adoption. Both the purchaser and recipient will receive information about Tseten’s life, photos of his journeys and a printable photograph of his paw print on ink obtained when he was first collared and tracked in 2015.


  1. In my heart I wish Tsetsen has moved on, but if he has passed he has left quite a legacy. Thank you for this tribute and the wonderful work of all involved in protecting these wonderful animals.

  2. Thank you for honoring Tsetsen and writing this tribute to him. WE are forever thank fun to him and to SNL for bringing us a little closer to the amazing life of this wild snow leopard. May he be in peace wherever he is!

  3. SLT it is such a privilege to know details about the Snow Leopards especially SL Tsetsen. Your study has made such an icon real and the privilege is knowing he lived and thrived in his domain, thank you.

  4. Thank you for the update. Tsetsen will never know how much he helped the SNT scientists, but those of us interested in the plight of the snow leopard do and we can honor him, each in our own way.

  5. Tsetsen was a wonderful ambassador for his species. I had the honor of winning his photo and paw print at your annual gala many many years ago. I see him daily. And I marvel at the incredible lives that snow leopards lead. RIP Tsetsen. You made a difference!

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