Blue sheep strategy to survive Himalayan predators

Kathmandu, Sept. 28: You often come across fights between predators and prey, where each side fights for their survival. In the high Himalayan region especially in Manang’s Nar Phu valleys, a snow leopard and a naur (Himalayan blue sheep), meet by chance while searching for food to survive in the tough environment.

The snow leopard aims to capture the naur for a meal, but the naur is determined to avoid the risk of being caught. This dynamic persists as long as these predators and prey coexist in the wild.

Snow leopards (scientifically known as Panthera uncia) are unique and are categorised as an endangered species in Nepal. These remarkable big cats inhabit the mountainous regions of Nepal, especially in the Himalayas, and their presence underscores the ecological importance of this region.

Efforts to protect and conserve the snow leopard population in Nepal are essential to ensure the survival of this magnificent species and to maintain the biodiversity of Nepal's high-altitude ecosystems, experts said.

"To safeguard the snow leopard population, it is imperative that we protect the naur, as they constitute a primary source of food for these magnificent cats in the high Himalayan regions," Ashok Subedi, Conservation Officer of the National Trust for Nature Conservation, said.

Naur serves as a crucial dietary component for these wild cats and plays a significant role in their survival. The presence of naur in the snow leopard's natural habitat is vital for maintaining the delicate ecological balance of these high-altitude ecosystems, Subedi said.

"Naur is currently listed as a species of the least concern in Nepal, but it could face risks due to the scarcity of pasture land and overgrazing by local livestock," Thapa warned.

In a recent study conducted in Manang and Nar Phu valleys, researchers have discovered that the naur faces predation from two very different predators -- the snow leopard and the wolf. This research sheds light on the complex dynamics of these high-altitude ecosystems and the interplay between predator and prey.

A study conducted by wildlife ecologist Kamal Thapa and Prof. Santosh Rayamajhi called “Anti-predator strategies of blue sheep (naur) under varied predator compositions: a comparison of snow leopard-inhabited valleys with and without wolves in Nepal” shows how naur navigate two different predators, snow leopards and wolves, in those valleys. 

According to Thapa, “We thought that naurs, which are highly alert animals, would change how they protect themselves based on the dangers posed by snow leopards and wolves,”

In the Manang Valley, naurs face a double threat, with both snow leopards and wolves as potential hunters. Conversely, the Nar Phu Valley presents a different scenario, with the snow leopard reigning as the primary predator.

In the Manang Valley, where both snow leopards and wolves live together, naurs showed a much higher level of alertness (15%) compared to their counterparts in the Nar Phu Valley (9%). 

This increased vigilance in the presence of both predators supports the idea that naurs spend more time detecting and reacting to danger when dealing with multiple threats, lead researcher Thapa explained.

Despite the differences in vigilance, the study noted that naurs in both valleys spent a similar proportion of their time foraging. This suggests that while the level of vigilance may vary, the overall foraging behaviour remains consistent, he said.

“Seasonal factors also played a role in naurs' behaviour. During the spring, naurs displayed increased vigilance, possibly due to poorer forage quality and limited foraging areas. However, during the autumn season, naurs formed larger groups, potentially as a strategy to dilute threat and confuse predators,” Thapa said,

In the Nar Phu Valley, where only snow leopards are present, naurs were observed using open terrain more frequently. This behaviour is attributed to the solitary stalking nature of snow leopards, which prefer breaks in terrain as stalking cover.

As the climate crisis and changes in local resources continue to evolve, further research is needed to understand and conserve the naur population and the broader ecosystem in these regions.