In addition to working with snow leopards, I also lead the lynx research in Sweden. By the mid-1900’s, large carnivores had been almost exterminated across Europe, with only small populations surviving in remote mountainous areas. The lynx in Sweden was no exception; when the species was protected in 1927, it is estimated that fewer than 100 individuals remained. Today, they have recovered remarkably and are spread across much of the country, mainly in the more densely populated southern regions, with an estimated 1,300–1,500 lynx in Sweden today.
Eurasian lynx prey primarily on ungulates (hoofed animals). In the northern half of Sweden, they feed mainly on semi-domestic reindeer owned by the Sámi people, Scandinavia’s indigenous reindeer herders, which is the main source of human-wildlife conflict today. In the south, lynx feed mainly on roe deer, but also hunt fallow deer (similar in size to a white-tailed deer), red deer, wild boar, and occasionally moose calves. They will also take smaller prey such as hares, grouse, and pheasants, though these are less important for adults.
A young lynx from our study at a moose carcass
Eurasian lynx have a fixed mating season, similar to snow leopards. While the snow leopard mating season is relatively broad—with matings documented from mid-January to late March—the lynx mating season is more concentrated, running from the last days of February to late March. Both species have similar litter sizes, ranging from 1 to 4 cubs or kittens, with an average of 2. Snow leopard females give birth for the first time at age three or four, while lynx females do so at age two or three.
While there are many similarities in the two species’ reproductive biology, the most striking difference is how much time mothers invest in raising their young. Lynx give birth every year and kittens leave their mother at around 10–11 months of age, whereas snow leopards give birth only every other year and cubs stay with their mother for 20–22 months. This means that lynxes have more than twice the reproductive capacity of snow leopards, and their populations can grow and recover much faster.
Of all wild cats, snow leopards invest the most in raising their young—caring for their cubs longer than any other species. We do not know exactly why that is. Part of the explanation is likely that hunting on steep mountain slopes is physically demanding and requires young cats to develop strong muscles and bones over a longer period. There is also very little ‘easy’ prey available for young snow leopards, such as hares. Young lynx, by contrast, have a variety of smaller, more accessible prey to practice on (hares, grouse, and the like), which likely helps them survive those first critical months on their own.
The graph below shows the prey choices of young versus adult lynx, and it is clear that juveniles target much easier prey before building up to larger quarry. For young snow leopards, the only comparably easy prey would be domestic goats, though they are herded. But even though goats are easier to catch than an ibex, young snow leopards rarely pursue them, most likely because they are wary of approaching while a herder is present. Adult snow leopards are typically bolder and will sometimes slip in to check whether any straggler has wandered off unattended.
Beyond these differences, and the obvious contrast in tail length, the two species are actually quite similar. We also use similar methods to study them. Lynx are captured using box-traps fitted with cameras and alarms. When an animal approaches, the camera takes a photo and sends it to my phone. If the animal is actually caught, a separate alarm sends me a text message. This lets us cover a large area with traps and respond quickly when needed. If the photo shows a non-target animal, a local contact goes to the trap and releases it—most often it turns out to be a badger. If it is a lynx, we drive out to collar it. Once we have finished our work, we place the lynx back inside, administer a reversal drug, and let it recover safely within the box. After 10–15 minutes, we open the doors and it walks out on its own.
To investigate what these cats are eating, we visit clusters of GPS locations where the animal has spent time, a sign that it may have made a kill. This is the same approach we use for snow leopards. The difference with lynx is that we rely on trained dogs to find the prey remains, since lynx commonly cover their kills with vegetation, making them hard to spot otherwise. I have a 13-year-old dog who is mostly retired these days; her one remaining job is to search for lynx kills. During predation studies, she sits on the porch every morning waiting for ‘her’ student to come and pick her up.
Studying both species side by side has given me a real appreciation for the challenges predators face to survive in a changing world. The lynx story in Sweden is, in many ways, an encouraging one—a predator that was nearly wiped out has come back, and we now have the tools and knowledge to manage that recovery while addressing the conflicts it brings. The snow leopard’s slow reproductive rate means that populations damaged by habitat loss, illegal hunting or retaliatory killing will recover more gradually. That’s why long-term monitoring and working with local communities are so critical for snow leopard conservation. The methods we use, GPS collars, camera traps, and old-fashioned fieldwork, help build the kind of knowledge that conservation decisions need to be built on. Both cats deserve a future, and understanding them as deeply as possible is our best chance of securing one.
Sign up for our monthly E-News to receive all the latest snow leopard conservation updates.
Photos: Henrik Andrén, Per Ahlqvist, Daniel Mallwitz, Julia van de Mundt.
Acknowledgments: The Eurasian lynx study is hosted at the Grimsö Wildlife Research Station, part of the Swedish University of Agricultural Sciences. We are deeply grateful to the Grimsö staff, whose expertise has been instrumental to our snow leopard research in Tost.