By Sharanya Dutta
Nishma Dahal, 29-year-old PhD scholar in Dr Uma Ramakrishnan’s lab in NCBS, Bangalore, recently discovered a new species of pika (a cute little mouse-like bunny that is all of 80-150 gms). She is interested in studying the evolutionary history of pikas to understand the origin and the history of one the Himalayas. Having travelled extensively in the Himalayas in 2010 to study the effect of climate change on pikas, Dahal’s discovery was a happy by-product of her research. We spoke to her about her journey over the very difficult Himalayan terrain and the process of verifying that she had, indeed, found a new species.
What was the purpose of your research on pika?
We were interested in studying the impacts of climate change on the Himalayan biota. Back then when NCBS got this funding from DBT in the year 2010, American pika research was making news. Few lower elevation populations were reported to have gone extinct and that was corroborated to increased temperature in those regions.
There have been studies in North America,where pikas are becoming extinct because they can’t adapt to the temperature changes due to global warming. There is extremely little data about pikas in the Himalayas. I was studying how biodiversity is impacted by climate change, and pikas seemed like the right species. They exist in high altitude, or temperate regions that are very cold. Pikas don’t even hibernate so they make for ideal control groups to study — if the habitat is so restricted, it’s easier to map how their habits change with the temperature — they either move up to higher altitudes, try and adapt to the changed climate, or become extinct.
How was this new species discovered?
I was sent to sample pikas in East Sikkim in my first field trip. I traveled across the Himalayas — in the eastern region I went to Sikkim and Arunachal, in Nepal I went to Langtang and Annapurna, and in the western regions, in higher altitudes, I went to Spiti and Ladakh. There’s no baseline data for this species, so one has to start with very basic questions. They’re really tiny so it’s very hard to actually catch one while wandering in the mountains, so I decided to collect their faecal pellets, and brought them back to the lab. Since they’re exclusively herbivores, there is no other vertebrate DNA in their faecal matter. Also, pika pellets are specific and very easy to identify in the field. No other small mammals have poop that looks similar to that of pikas. We used vertebrate primers and compared them to other samples. Once we did the analysis, I realised that it was not at all similar to pikas that were known, especially the Ochotona thibetana sikimaria, which it was earlier mistaken for. So I had to collaborate with the Zoological Museum of Moscow (the curator of whom co-authored my paper), the Chinese Academy of Sciences, and Stanford University, to get more specific data on these possible sister species. China was especially important because of the 28 species of pika that exist globally, China has 26 of them.
What does it mean when a species is discovered? Is the process tedious?
It takes a lot of time to verify that it is indeed a new species. This is especially true for the pika, which is a species with cryptic lineage, that is, where it’s morphologically similar to one species, but genetically dissimilar. So from the name of the better known species, we removed the thibetana and this new species is now Ochotona sikimaria.
What was it like to do research in the Himalayas?
I’m from Sikkim, so it really helped that I spoke the local language. I usually took local field assistants because it made the most sense both financially and otherwise. You get to stay in their homes, and they feed you, so it’s great. In Nepal, a student doing his Masters there travelled with me. In Sikkim, my cousin travelled with me before I realised it was safe to travel with strangers. They’re extremely helpful, and shy in terms of photographing me and things like that. It was also really funny, because they didn’t remember my name, because it isn’t common in the area — so I became ‘the girl who studies mouse’. In terms of the local climate, it was the hardest in Sikkim. There were no roads in the elevations we had to go to, to sample the pika. The climb was from 2,000 metres to a 4,800-metre elevation and when we reached, it started snowing. We couldn’t stay in the tent and finally we had to take shelter under a rock. I used to travel for about a month at a time, and most places didn’t have very sanitary facilities, but the people were great so it worked out.