How SLIMS Works
Since wild snow leopards are very rarely seen, it is almost impossible to count them directly. Luckily for biologists, however, they leave ample evidence – indicating their presence – in the form of pugmarks, scrapes, feces, and scent-sprays as they travel about their home ranges. George Schaller, Rodney Jackson, Gary Ahlborn and others showed that snow leopards exhibited a special predilection for traveling along well-defined ridgelines, along the base of cliffs, in narrow valleys or drainages, or across high passes and cols connecting different watersheds.
The first step in undertaking a SLIMS survey is to consult the literature or contact experts to determine which areas are known or suspected to harbor snow leopard. Next is to run a sign transect in the field after identifying suitable survey areas. Transects involve walking along suspected snow leopard travel routes and counting the type and number of sign seen. (for a discussion of transects in greater detail, see “Snow Leopard Sign and Marking Patterns”.) Transects may vary in length from a few hundred yards to a mile or more. Local people should also be interviewed to determine where snow leopards have been seen and how often. Information should be gathered on the main threats to the species (such as poaching, depletion of the prey base, and retributive killing by herders as a result of heavy livestock depredation).
The best times to conduct sign transect surveys are in late spring or early summer, and again in the fall, before the onset of the winter’s snowfall.