By S. Jalihal
I always wondered what the Nicobar Islands would be like. While preparing for my trip there, I packed my snorkeling gear, excited at the prospect of exploring the glassy blue waters surrounding the island. I hoped to swim above coral reefs and have unique encounters with a variety of fish of different shapes, colours and sizes. However, soon after my arrival, I was disappointed to see sign-boards on beaches that declared ‘Swimming not allowed’ – I later learnt the reason for this was the sudden increase in the depth of the waters near Great Nicobar’s beaches, and the abundance of crocodiles here. This itself is the perfect example of how enigmatic the island is: wildly unpredictable, brimming with diverse life-forms and supporting the many habitats that nurture them. After spending a few days here, I tucked my snorkeling gear deep into my backpack and began looking at the island through a fresh lens – stripped off of the usual expectations that short-term travelers tend to have when they visit coastal spaces.
If the island were a play, it would have three main acts – the forest, the shore, and the underwater. Scenes change as the day progresses, and different creatures take charge of the play. While some stand out in their extravagant costumes, others camouflage themselves in the surroundings, quietly playing out their respective roles. Yet others take centre stage, creating loud but harmonious sounds. Stage lighting duties are shared by the sun, moon, stars and the clouds, all collaborating to create a unique backdrop for each performance. And, of course, the frequent and unpredictable showers the island receives can be relied upon to enhance any dramatic scene with noisy patter.
Hermit crabs are decapod crustaceans, with a soft abdomen unlike other crustaceans. They are well known for their behaviour of occupying a discarded seashell to protect their soft abdomens. Photo: Gobind Sagar Bhardwaj.
On most days, the sun rises around five a.m. On shore the waves are calm, slowly creating haphazard patterns on wet sand. Against the backdrop of a rosy-hued sky and in contrast with the azure water, thrifty hermit crabs busy themselves with finishing the night’s work. Supporting actors of the intertidal ecosystem, they are seen exchanging the borrowed, patterned shells they have outgrown. Usually standing in a file of ‘size order’, larger crabs pass on their shells to the smaller ones. Few groups of crabs, more chaotic than the ones that queue up, create a tiny traffic jam on the beach. At this time, these soft-bodied crustaceans feel the most vulnerable as they scurry to find fitting, new shells for protection. Scientists call this hierarchical shell exchange a ‘vacancy chain’. Similar sized crabs often combat for a single shell, and their existing shells create clunking sounds when they hit each other. If alert enough, one can also see ghost crabs that casually camouflage with the sand, disappearing at the slightest movement, and reappearing to make the sand look like it is moving on its own. Both the crabs are predominantly active at night, only to retire by sunrise.
Within a few minutes, Nicobar long-tailed macaques, the second largest mammals on Great Nicobar (after the wild pig), get active. Living in groups of different sizes, these primates are found on the coast, in the forest and near urban settlements. They feed on a varied diet of pandanus, coconuts, rhino beetles and fruits such as jaiphal and papaya. When a morsel is too thorny or muddy, they perform an interesting ‘leaf wrapping’ behaviour. They look for the nearest bush and haphazardly cover and rub the food with the bush or with a single plucked leaf as if wiping it before consumption. These superstars are particular about grooming. They even seem to floss their teeth with slender casuarina twigs or similar material after feasting!
Later in the day, White-nest Swiftlets, Racket-tailed Drongos, Crimson Sunbirds and water birds such as the Water Cock and the Pond Heron are seen carrying out different tasks. While some are better individual workers, others chatter in groups, like a synchronous choir in the play. Some are seen around Campbell Bay, the main human-inhabited part of the island. Others are spotted in coastal forests such as the one in Galathea Bay or the Great Nicobar Biosphere Reserve. Among the birds living in coastal forests, the undisputed show stopper is the endemic Nicobar Megapode (‘megapode’ translates to ‘big feet’).
These brown birds somewhat resemble chickens. They build mounds like ingenious architects, carefully picking a tree that will support their elaborate constructions. Unlike other birds, megapodes do not incubate their eggs to regulate their temperature (around 330C). Incubation relies instead upon the decomposition of dried leaves and twigs that form the mound. Mother megapodes regularly check the temperature of the mound using thermometer-like feet, ensuring that their offspring are doing fine. The chicks are able to hunt, walk and fly on the day they emerge from their pinkish eggs!
The Nicobar Pigeon is another endemic species in Nicobar. Genetic analysis reveal they are the closest living relatives of the dodo, thus, looked upon as icons of morphological evolution. Sometimes, they appear in other plays with different backdrops too, as these pigeons are island hoppers. In fact, one of them is also known to have appeared all the way across the southern Indian Ocean on the shores of Australia! They have colourful iridescent feathers that shine brightly in the sunlight. This is a costume shared by the sunbeam snake, which is otherwise purplish-black. Light creates a rainbow effect on the snake’s skin. The beautiful reticulate python, known for the perfectly geometrical patterns that cover its body, also occupies the same forest.
The Nicobar long-tailed macaque and Nicobar treeshrew are endemic to the Nicobar Islands. Photo: Gobind Sagar Bhardwaj.
The latter is a primarily arboreal mammal. It is omnivorous, and spends most of its time foraging. Both mammals are now facing habitat loss in addition to other existing threats on account of the denotification of the Galathea Bay Wildlife Sanctuary. Photo: Ravi Shankar P.
The former inhabits mangroves, coastal forests, as well as inland forests. Photo: Saurav Harikumar.
Throughout the day and night, the act of the forests is quite the musical. The angry and calming tunes of the waves are not the only sounds one hears. Strong winds create a choir of pandanus leaves that sound like natural wind chimes or wooden sticks striking against each other, resembling a continuous, polite ‘dandiya’. A large flock of Glossy Starlings fly by, chattering away in their groups, ready to perch on the tallest tree they can find. Winds make the trees whisper to one another – perhaps about the rainfall patterns that they play a role in defining. The macaques make a variety of sounds from morning to early evening. They make sharp-chirpy sounds or raise alarm calls to alert group members of potential threats. The alpha male uses a krackow call to integrate scattered troop members just before they move to a roosting spot and call it a day. The young ones, unaffected by the alpha’s command, continue their antics and resist their mothers’ tugs (a slight argument ensuing, perhaps) just so they can play a little longer. These macaque moms are often seen relying on their older daughters and sisters to babysit their infants while they forage for food. Amidst the chaos of the macaques, bird calls are heard. Some even resemble a crying child at a distance. Despite spending a good amount of time in the dense thickets, it is difficult to spot all the birds singing in their unique voices. A coarse cackling sound is followed by a gurgling one – like bubbles popping rapidly. Some bird calls even resemble a flowing stream. These melodious tunes are followed by a sharp whistle, accompanied by the singing of the cuckoo and the muffled buzzing of a wasp.
No play is complete without some adrenaline-pumping action. The Nicobar treeshrew, that looks much like a squirrel, is the star attraction in the forest scene. Performing stunning aerial stunts, these gifted gymnasts thrive in the dense rainforests as well as littoral patches on the islands of Little and Great Nicobar. They are often seen resting comfortably around branches below vine-covered canopies or sub-canopies with their tails curled towards their bodies. At other times, adults and adolescents are seen squabbling on branches – either in pairs or in groups of four or five. Another interesting crustacean is the giant coconut crab, also known as the robber crab (Sanctuary Vol. XII No. 1, February 1992). Terrestrial creatures, they possess a very well-developed sense of smell. Being scavengers, they eat virtually anything left unattended – thus the title ‘robbers’ or ‘thieves’. The coconut crab is also called so because of their nocturnal habit of using their pincers to dig into coconuts.
The trees in the forests on the island have claimed their own spaces, but also share them with woody and soft green climbers that look like they are hugging them. These climbers form interesting shapes – checkered designs and helical structures that resemble DNA. Some trees have stilt roots and form natural swings in the forests, often occupied by a pair of amorous birds. The trees are tall, and the forest floor appears like a racetrack on which trees compete to see which grows the tallest. The thickness of the rainforest leaves little space for light penetration to the ground, leaving the forest floor dark and dim. Together with moistness, this encourages the growth of different varieties of mushroom – some white, others black, red or brown. Wherever shafts of light negotiate their way through the thick canopy, an ethereal glow illuminates the leaves and branches. At night, biofluorescent mushrooms and bioluminescent fireflies resemble sparkling diamonds as they light up the forest wonderland!
A brain coral is juxtaposed against a colourful sunset on the Nicobar shore. The forest, the shore, and the underwater are the three main “play acts” for Great Nicobar, with various creatures taking centre stage during different times of the day. Photo: Gobind Sagar Bhardwaj.
Back on shore, the sea is as active during the day as it is at night. When the waves hit the shore, at several places on the beach, corals are deposited instead of shells. They are statements of beauty unto themselves, characterised by the Golden Ratio and the Fibonacci sequence patterns they carry (some branching, others laminar and columnar), making a nature artist yearn to sit on the sweltering sand and sketch them. Adding to the beauty, acorn barnacles form curtain-like geometric patterns on rocks and moist trunks. The quiet horizon suddenly comes to life when a pod of dolphins passes by, cheerfully playing with one another, or competing with the waves by leaping higher every time. Making a much-awaited special appearance in the play are flying fish, the enigmatic stars of the open sea that grab all attention by staying true to their name. Then there are the saltwater crocodiles, which, like stately patriarchs of a period film, silently guard the estuaries and freshwater streams of the island.
Back on the shore as night begins to fall, stars begin their magic. Not marred by light pollution, the stars in the island sky are clearly visible, glittering unhidden by clouds that carry rain. Sometimes the sky bears a tinge of pink too, with the appearance of the Milky Way. Bioluminescent zooplankton are visible in the water when waves touch the sand. The imagery is that of stars having fallen into the ocean – quite elusively, letting spectators catch a mere glimpse. Nights are usually when mother leatherbacks or olive ridley turtles emerge, ready to lay their eggs in the fine sand. The same night also sees tiny turtle hatchlings emerge from other nests… all bite-sized temptations for water monitor lizards, wild pigs and dogs that lie in wait.
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Acorn barnacle is the common name for a number of stalkless species of barnacles.They belong to the same order Crustacea as crabs and lobsters, but are sessile (nonmobile) as adults, growing their shells directly on the substrate. Photo: Saurav Harikumar.
The Great Nicobar Biosphere Reserve and the recently de-notified Galathea Wildlife Sanctuary together extend over land and all the way into the coastal waters. The rich seas surround the dense forests of the island, giving rise to distinct ecosystems that house several endemic species. Every square centimetre of the island hosts a variety of organisms – so dense, that each tries to claim its own space. All lifeforms play their own special roles, each more interesting and critical as the other.
Yet, because of limited research, we have thus far discovered all too little about the living wonders of these magical isles. We know a mere handful of the actors, directors, and sound and light managers of the spectacle. The dynamism and enigma of this unique island has a strange coherence to it, making the Great Nicobar production a thrilling, yet calming one, exclusive to this island.
And this show must go on!
S. Jalihal graduated with a degree in Environmental Studies and Public Policy from FLAME University, Pune. She is interested in studying different ecosystems around India and currently works at the Centre for Knowledge Alternatives, FLAME University. In her free time, she likes to paint the biodiversity she sees around her.
