Whether you’re on a casual stroll on a trail along a gushing mountain river, or on an arduous climb up into the high elevations of the trans-Himalaya, you might well see a flash of fur, a glimpse of a tiny creature scampering about on the ground. Many of us mistake them for some sort of rodent. Few of us realise that these scurrying little mountain companions –weighing only 60 to 400g, are actually lagomorphs, a group consisting of hares and rabbits. They are known as pika.
Though different species are found across North America and Central Asia, the Himalayas are home to a diverse variety of pikas too. But they are all too often neglected in the landscape of other majestic species such as snow leopards and wolves. Yet, these rather tiny “mouse-hares” have a unique story to tell us, and Nishma Dahal is one of the few researchers listening. To understand the distribution of the various species of Pikas across the Himalaya, she spent many months in Arunachal Pradesh (mainly Tawang), Sikkim, Nepal (Lantang and Annapurna Conservation Area), Himachal Pradesh (Spiti Valley) and Ladakh, between 2010-2015.
Many people think of pikas as one species. But there are supposedly seven species of pika found across the five Himalayan states of India. All of them are high altitude specialists, with some species even spotted around 6000m. This is staggering, considering even the most specialist mountain species like Snow Leopards struggle to survive over 5,500m! Some pikas make burrows and others live in talus' or natural rock openings.
Pikas are built for cold and hypoxic, or low-oxygen, high-altitude environments. Their thick fur coat means that they aren’t suited to hot temperatures. With climate change, especially global warming, manifesting itself more prominently in the high-altitude mountains, the pika might be unable to adapt and survive the temperature rise. The extinction of low-elevation populations in North America is a clear indicator of their vulnerability to global warming.
Pika populations can be used as an indicator of the health of their high-altitude cold environment, the source of some of the most important life-giving rivers on the Indian plains – like the Ganges. Therefore, safeguarding the pika habitat means safeguarding the mountain environment that ensures water flow in the rivers of the lower plains.
Though perhaps not as charismatic as some of the other larger species in this habitat, pikas offer a wealth of ecosystem services. They serve as food for a number of predators such as the Red Fox, birds of prey (eagles and hawks) and weasels. They are also ecosystem engineers – their foraging and burrowing help promote the diversity and distribution of various plant species and nutrients.
The chilling freeze of the high Himalayan winter, where temperatures can plunge down to 30 degrees below zero, weakens even the strongest and largest of animals. Many mammals such as bears choose to hibernate through the intense winter months. However, pikas are active even in the depth of the cold. They are known to collect and dry vegetation in the summer and stack them into hay piles in and around their burrow to feed on in the winter. The drying reduces the secondary metabolites present in the vegetation, making it edible. Secondary metabolites are compounds – either toxic or repulsive-smelling – that deter species from eating the plant. High-altitude plants in particular need these to ensure they don’t get damaged in the harsh environmental conditions they exist in.
To truly understand the species diversity and distribution of pikas, we have to get tissue samples for genetic analysis. One of the best ways to obtain fresh tissue samples is by capturing pikas in live baited traps such as the one pictured here. Often, traps are placed at entrances of potential pika burrows or openings in rock talus’ that pikas use as refuges. All varieties of bait, from peanut butter and ginger to apples, are used to lure these creatures into the trap.
Capturing pikas is a game won by patience. All pika species are diurnal – they are active during the day and sleep at night, like us (well, most of us). Traps are placed just before sunrise. Then, until a trap gets triggered and an individual is caught, the team has to sit and wait in anticipation. Upon trapping an individual, it is held and a snip of skin from its ear is taken and preserved for genetic testing in the National Centre for Biological Sciences (NCBS) laboratory in Bangalore.
Pikas thrive in some of the most beautiful yet hostile environments in the Himalaya. In the Himalayan high altitudes, the weather is extremely erratic. What is a clear blue sky now can be heavy with snow-laden clouds a moment later.
The perks of fieldwork are the surprises that are in store. Who would have thought, for instance, that when we set out traps for pikas we would capture a snowfinch species! Apparently, burrows made by pikas such as the Plateau Pika are also used as refuges by birds such as snowfinches and other small mammals such as voles, especially during snowstorms. Some theories suggest that these birds use pika burrows as foraging grounds for insects as well.
At this point, it is hard to say how many species there are or how they are distributed. Only recently did we learn that the Sikkim Pika, indistinguishable from the Moupin’s Pika in appearance, is a genetically distinct species. As for the Forrest's Pikas, which also live in Sikkim, we know even less.
All three species are said to be found in parts of Sikkim or Arunachal Pradesh and are thought to live around the tree line—the region on a mountain where the trees end and the shrubby habitats of higher altitudes begin. Truly, our knowledge about pikas is at a nascent stage. So remember, it is important to be on the lookout for these furry creatures during your Himalayan journeys, for each tiny piece of information we glean can be vital to understanding these unique species and their habitat.
It’s not just their thick fur coat that makes pikas so amazingly adapted to the cold. When mammals feel cold, they shiver, a muscle response that heats them up. Or, they put on weight in the autumn and hibernate through the winter. But pikas, which stay active throughout the year, are known to have non-shivering thermogenesis – they stay warm because of their high metabolic rate, which leads to constant feeding. Surely a recipe for obesity, one would think.
So how do they maintain their health whilst staying fed and warm? Well, there are two types of fats: White adipose tissue (WAT) used for energy storage and Brown adipose tissue (BAT) used for energy expenditure and thermogenesis. Pikas are known to convert WAT to BAT with increasing altitude, thus using their fat as a means to stay warm and be metabolically active. No wonder pikas aren’t diet conscious!
Some social pika species live and act in groups, where individuals have different roles. Though our knowledge is limited, we know that some pika species have a large vocal repertoire which they use for a variety of social interactions, such as to mark territories, for instance. Individuals living in groups, like the one pictured here, stay vigilant for predators and yelp a particular call to alert their peers upon spotting danger.
Some pika species live in and around high-altitude human-use landscapes, such as the Spiti Valley. Some of these areas are home to agro-pastoral communities that depend on the cultivation of crops such as pea and barley, apart from livestock herding, as their main source of income. Often, pikas forage on their cultivated crops or intensively graze the pastures which are meant for livestock, thus coming in conflict with human interests. In some areas across their range, communities are known to retaliate by poisoning them to reduce the damage.
Though it may seem ironic, the fate of some of the tallest and most majestic Himalayan mountains can be better understood by studying some of its tiniest mammal occupants, the pikas. So the next time you sight a mighty peak, remember that below the peak somewhere, tiny, furry pikas are living their busy lives, all the while ensuring the stability of this fragile and critical ecosystem.