The Frog’s Prints

 

February 2004: Working with frogs brings a strange but intense awareness about the present and distant past. Frogs created the first true footprints on earth at least 190 million years ago by the side of some freshwater swamp. This colonisation of the land is an epoch in the history of evolution. From the time I first got interested in frog research, the image created by my mind's eye of the first frogs tentatively crawling out of the primordial soup on to dry land has haunted me.

But in spite of the revolution that frogs brought into evolution, they have not always enjoyed pride of place either in folklore (the ‘ugly' frog waiting to be transformed into a handsome prince!) or in science. Even Linnaeus, father of the modern system of naming species, had the following (and surprising!)comment on frogs - “ … most amphibia are abhorrent because of their cold body, pale colour, cartilaginous skeleton, filthy skin, fierce aspect, calculating eye, offensive smell, harsh voice and squalid habitation; and so their Creator has not exerted his powers (to make) many of them…". (from Systema Naturae - 1758). Frogs thus unfortunately had a bad start in biological sciences at the very time when species names were being developed and finalised.

Fortunately, in spite of such unfavourable treatment, fascination for the study of frogs has increased. Frog study includes basic sciences like taxonomy and advanced fields like evolutionary biology and molecular phylogeny. Frog data is increasingly used as clinching evidence in questions relating to land mass movement. Frogs are an exceptionally sensitive indicator of land mass movement since they never cross stretches of oceans. The relative progress of these disciplines varies vastly from country to country. The United States and some European countries are miles ahead in most of these fields whereas many other countries including India are only slowly waking up to the realisation that the study of frogs opens up a veritable scientific treasure chest.

I took my first tentative steps in frog study through photographing frogs, which led to observation and astonishing findings about different species and how they lived. Since I worked as a plant taxonomist, formal funding for such studies was not available, as our scientific bureaucracy maintained that a plant taxonomist has no business dabbling in frogs. But my fascination for the subject only grew and the support of family and friends helped overcome these obstacles. Particular mention must be made of my many tribal friends who proved to be astute observers with an astonishing knowledge bank and their own brand of natural history.

In the beginning, I chose to study the Western Ghats of Kerala, mainly because it was closest to where I stay and easily reachable on my motorcycle! The monsoon months were always times of hectic activity. In Kerala, people save, to tide over the monsoon months. I too saved up, but with the objective of financing my field trips! When my own resources were too meagre, friends pitched in and I owe them a debt of gratitude.

 

The monsoon is the time when frogs go mad with activity. A typical day of frog-hunting fieldwork starts at seven in the evening, when darkness descends over the forest. The combined effect of monsoon and darkness casts a reproductive spell on the frogs. Typically, most activity is in the amphitheater of some water body or the other. The air resounds with diverse calls, but it is not easy to spot the caller. A diligent search with flashlights, combined with a gift for locating sounds, is required. And it is all too easy to mistake the author of the sounds. After a prolonged search, I once found, to my intense embarrassment, that the frog I was tracking was actually a bush cricket!

One evening, at the height of the monsoon, I was waiting at the foothills of the Agasthyamala hill range for night to fall. With me was Anil Zachariah, a veterinary surgeon with a passionate interest in natural history, and my good friend Vijayan, a tribal from Kanis in Kerala who accompanied me on most of my trips and was at home in any habitat, in any weather and at any time, day or night. On many occasions, we have watched breathlessly as Vijayan effortlessly climbed trees in almost total darkness, guided only by the call of a tree frog!

With the sun slowly disappearing over the forest horizon and darkness taking over, the frogs started calling. Among the assortment of calls, there was one that seemed rather curious… trick… tic… trick. Anil immediately pronounced that this could be a new frog. I have tremendous respect for Anil's frog-call identifying skills, but because of my earlier experience with the bush cricket, I remained sceptical. Anil was supremely confident however, and a few minutes of careful search revealed the frog! This turned out to be the smallest frog recorded from the Western Ghats and a new species of bush frog - Philautus.

The Western Ghats ranges from the state of Maharashtra in the north to Tamil Nadu in the south, spanning a length of 1,600 km. The mountains have a range of vegetation from tropical evergreen to degraded forest patches along the fringes. Frog habitats in the Western Ghats are extremely varied, with different species making themselves at home in water, near water, in stagnant streams, flowing streams, under the ground and on treetops. My fieldwork in the Western Ghats revealed about 100 new species of frogs, lengthening the inventory of frogs in the Western Ghats from 106 to probably over 200! This included a new genus of canopy frogs, usually found at heights of about 20 m.

 

Such a doubling of species is unusual. The first and most natural question is - are they actually new species or are they merely colour variations or other morphological variations of the same species? The answer to this could become quite complex and involves the established principles of taxonomy. The characteristic of each species known to science is described using a standard protocol. In addition, one specimen of the species is also held in a museum of repute somewhere in the world. This specimen is called the ‘type'. Hence if there is a suspected new species, it needs to be compared against existing types and original descriptions of species. In proposing new species from the Western Ghats, I have used this internationally accepted methodology.

Incidentally, when I visited some museums, particularly the British Museum of Natural History, London and Museum of Zoological Survey of India, Kolkata and Chennai, I found specimens of at least 30 per cent of what I proposed as being new species. But these had been identified differently, probably according to the information available at the time of study.

Another important question that needs to be addressed is why did so many new species come up in the relatively short time of a decade? The answer is beyond me, but I would guess that the rich haul of new species came up only because they were looked for intensively. From my experience, I am reasonably certain that a casual examination of these habitats will not reveal all its riches. It calls for determined searches in areas of high probability. The saying that ‘the eye does not see what the mind does not know' is perfectly applicable in natural history fieldwork.

In addition to these new species, the Western Ghats also yielded one new family and four new genera. I have published my paper describing one family Nasikabatrachidae and one genus Minervarya and the rest await publication.

Aside from revealing new species and genera, the study also looked at the reproductive modes of frogs, including behaviour relating to egg laying and how the metamorphosis takes place. World literature on frogs lists 29 reproductive modes, but the study of the Western Ghats has added two more reproductive modes to this list.

The old school of taxonomy was a static science while the incorporation of other information like behaviour characteristics has made modern taxonomy more dynamic. When more information about currently accepted species is considered, even the placement of a frog in a specific genus or species becomes challenged. The results from the Western Ghats have provided information that raises issues of taxonomic rearrangement, which will take some time to be resolved satisfactorily.

 

Research in India

Frog study in India has gone through more or less distinct phases. During the colonial period there was an interesting symbiosis between the natural history approach and the professional approach. Individuals who worked predominantly from a natural history angle (R.H. Beddome, T.C. Jerdon, H.S. Ferguson and others), collected specimens, which were deposited in the British Museum of Natural History, London. Professionals working from their museum desks (such as George Albert Boulenger and Albert C.D.G. Gunther) described these species without ever having set eyes on a single living specimen, let alone the species in its habitat. When taxonomic decisions were taken through such processes, it is no surprise that the modern taxonomist armed with a much wider range of information on a specimen, places it in a completely different taxonomic slot.

The momentum generated by these early pioneers could not be sustained and frog study became sporadic and confined to less thorough and sustained initiatives. Against this background of largely desultory work, some individuals have made major contributions in post-Independence India. C.R. Narayan Rao, Zoology teacher in the University of Mysore, Dr. R.S. Pillai, retired Deputy Director of the Zoological Survey of India, Dr. S.K. Dutta, Professor of Zoology and herpetologist from Utkal University and Dr. Indraneil Das, Professor of Zoology and herpetologist, University of Malaysia, Sarawak, have contributed significantly to the field, including through the description of several new species.

 

C.R.N. Rao is sadly no more with us and his contributions have been more misunderstood than appreciated. I strongly suspect that his failure to deposit the type specimens in recognised museums could have led to their disappearance from local colleges for various reasons.  Brief and incomplete descriptions of new species combined with the absence of specimens led to many of Rao's findings being discredited by other researchers. This was an indirect challenge to Indian science, a challenge to which there were no objective responses.

Vindicating C.R.N. Rao

One of my greatest personal triumphs has been the vindication of C.R.N. Rao's findings. I decided to retrace Rao's collection routes in Karnataka (Bhagmandla, Kempholey, Kottigehar, Saklespur, Wattakole, etc.). To plan the expedition that would retrace and hopefully relive Rao's expedition, I first contacted K. Jayaram, a meticulous wildlife photographer and my companion on numerous field trips. We also decided to consult T.N.A. Perumal, veteran of Indian wildlife photography. The three of us were equally keen on this expedition and we invited R. Dev, another wildlife photo-enthusiast and Vijayan, my regular expedition companion to come along.

Armed with Rao's original descriptions and searching only for those species, we set out on an 11-day expedition. Each day in the field yielded at least one species that we were looking for and with each species the excitement of the expedition increased. We located Bufo ‘brevirostris', Micrixalus kottigeharensis, Nyctibatrachus ‘kempholeyensis', Nyctibatrachus sanctipalustris, Philautus charius, Ramanella mormorata, Rana ‘intermedius'. But there was still one missing, a species that I was particularly looking for - Rana ‘gracilis montanus'. I find it difficult to explain my fascination for this species. Perhaps it is due to the fact that this is a large species, or maybe this was a field challenge for identification. Or it could also have been because Rao was particularly criticised for his description of this frog. Whatever my motivation, Rana ‘gracilis montanus' remained elusive. I had seen one living specimen of Rana gracilis in Sri Lanka in 1999 along with Kelum Manamendra-Arachi, a leading Sri Lankan amphibian expert.

 

Almost like a movie script, things started happening on the last day of the expedition. I had resigned myself to closing the expedition without locating my quarry. My disappointment must have been quite visible, but K. Jayaram was not one to give up so easily. He suggested that we give it one more try and we all agreed. In belting rain we reached a stream in full flow. Leaving nothing to chance, we searched under leaves and logs and in the crevices of wet rocks, our frog's favourite resting spot. And suddenly everything happened in a flash. From somewhere, a large frog propelled itself into the stream. Vijayan and I launched ourselves simultaneously into the stream after the frog. Regaining our balance, we searched furiously along the water's edge, since this frog has the habit of moving along a stream's edges. Vijayan soon held aloft a large frog. I had no doubt at all that it was Rana ‘gracilis', though I had to wait for systematic identification. The entire expedition team erupted in uninhibited joy and promptly started photographing the large, bright coloured frog. Even a Bollywood actress would not have been subjected to so many flashlights in so short a time!

I was delighted. The expedition had located nine out of ‘Rao's 18 species' and to top it all, Rana gracilis montanus also revealed itself on the last day of the expedition. C.R.N. Rao stood vindicated. I am now in the process of working towards systematically documenting these findings according to taxonomic protocols.

Frogs are primordial custodians of land by virtue of being the first to step on land. Life on land, and land itself, has evolved through millennia into a bewildering variety of life forms. But millions of years of creation is now being continuously threatened by human activity, and decisions taken in a few minutes can wipe out creatures and ecosystems that took millennia to evolve.

Frogs are often forgotten on platforms where conservation is discussed. But this first denizen of the land is a very sensitive indicator of what is happening to the environment. Frog study and documentation of details is thus a key aspect of biodiversity documentation. Once gathered, baseline information can serve as a benchmark against which regular data for monitoring the health of the forests can be judged. One might even say ‘if frog populations are healthy, then the forests they inhabit are also likely to be healthy'. The monsoon chorus of frogs in the forest is a reaffirmation of the health of that forest and signals a vital victory for conservation.

by S.D. Biju, Sanctuary Asia, Vol XXIV No. 1, February 2004