doi:10.1038/nindia.2014.168 Published online 11 December 2014

The smelly world of tiger pheromones

Veteran wildlife biologist Ratan Lal Brahmachary is a pioneer in tiger pheromone research. He discusses conservation and his recently published book ‘Neurobiology of Chemical Communication’ with Shubhobroto Ghosh.*

Ratan Lal Brahmachary

Q. What does your newly published book talk about?

A. This book is a compendium of research on pheromones and chemical communication. Specialists have contributed different chapters on pheromones and chemical communication in insects and vertebrates. My contribution is a summary of 50 years of research with colleagues on pheromones in tigers and other big cats. George Schaller and I started this research in 1964 while watching a herd of axis deer in the Kanha National Park.

Q. Tell us about your work on the tiger urine molecule.

A. My colleague, the late Jyotirmoy Dutta of Bose Institute, and I followed by our student and colleague Mousumi Poddar Sarkar made the first comprehensive approach towards this. The molecule 2 acetyl-1-pyrroline (2AP) is present in tiger urine (marking fluid) and is the very same molecule that imparts the beautiful aroma to fragrant varieties of rice like basmati.

Q. What are the trends in pheromone research in India?

A. Govindaraju Archunan of Bharathidasan University has done good work on cattle pheromones. C J Dominic in Benaras Hindu University and K M Alexander in Chennai did some good work on pheromones in rodents some years ago. In insect research, although India is rich in biodiversity and offers a vast scope of research, this branch of science is also becoming highly sophisticated requiring very expensive modern apparatus. This puts us at a disadvantage.

Q. What have been the landmarks in pheromone research across the world?

A. In late 19th century, the celebrated French naturalist Jean Henri Fabre initiated it in moths. He rightly conceived that certain smell molecules from the female moth attract the males. Unfortunately, he further speculated on unknown radiations from the female and thus lost the right trail. In the mammalian world, in 1964, George Schaller was toying with the idea of tigers leaving some messages in their scent marking. This science was then in its infancy. Only two mammalian pheromones (of musk deer and civet) were known. By about 1976, the study of mammalian pheromones came of age.

In 150 years of blood sport literature, the phenomenon of what now goes by the name of scent marking was conspicuous by its absence. Surprisingly stalwarts like James Inglis, Dunbar Brander and Jim Corbett seemed to have been absolutely oblivious of this important behaviour pattern which is now known to so many casual observers and tourists photographing or filming this phenomenon. Conservationist Valmik Thapar says he noticed it only after 1980.

In 1954, Colonel Locke in Malaya in his famous book ‘Tigers of Trengannu’ tersely but clearly described the fact and surmised what we know today to be correct. It was Schaller who first brought this to the notice of the scientists through his book, ‘The Deer and the Tiger’ (1967).  Eric Albone in Great Britain was the first person who tried to chemically analyse this material from tigers and lions, but he had no opportunity of observing these big cats in the wild.

Q. What about human pheromones?

A. Human pheromones constitute a terribly controversial subject. Tristram D. Wyatt of Oxford has discussed this subject in detail in ‘The Neurobiology of Chemical Communication.’ I feel that in the distant ancestry of the human species, pheromones played a role but by now only a vestige remains.

Q. How does research in biology compare to that in physical sciences, which you undertook in the early phase of your life?

A. Biology is as fascinating as probing the mysteries of the physical universe. The “inner universe” of an organism or of an ecosystem is as challenging as the “outer Universe" of the expanding cosmos.

Q. Do you think the contribution of stalwarts in biological sciences like Jagadish Chandra Bose and Gopal Chandra Bhattacharya has been properly acknowledged in India?

A. Perhaps they are not so clearly acknowledged although the present generation of scientists are following the same line through their studies and research. I would particularly mention scientists such as Raghavendra Gadagkar  at the Indian Institute of Science in Bangalore conducting research on wasps, late M K Chandrasekharan’s research on biological clocks in animals and plants, Raman Sukumar's on elephants and Rene Borges work on fig trees and insects. They are following the path laid out by Gopal Chandra Bhattacharya and Jagadish Chandra Bose.

Q. What are your views on science and conservation given that you are also a founder member of the Born Free Foundation?

A. I am primarily a researcher, secondarily or thirdly a conservation activist. The two are inseparably interrelated. How can I study tigers if the tiger becomes extinct before completing my studies? How can the conservationists take proper steps to conserve the tiger unless we find out some principles and data through research? All said and done, the appeal for conservation nonetheless is wider because even non-scientists love the world of animals and plants. Many people do not want to kill animals or cut down trees on religious grounds. Others are learning the basic principles of ecology and doing the same.

Q. What does the future of pheromone research in animals look like?

A. The Indian Institute of Science in Bangalore represents the hub for future research in this area. A lot of work can be done on pheromones and many ethological aspects of animals in India, Africa and Latin America, because biodiversity is very high in these areas. Almost every plant and animal offers some challenging problem or other and a lot of amazing facts await discovery.

*Shubhobroto Ghosh is a former journalist currently working with the World Wide Fund for Nature (WWF), New Delhi.