| Wading ankle-deep through a stream & then scrambling forward on all fours, I looked up to see one of the world’s most silent predators, inches from my nose, on a tree trunk. Cryptically camouflaged, the brown scorpion (Mesobuthus tamulus) was trapped in the light of my miner’s
head-lamp, but when I switched it off a second or two after photographing it, the arachnid vanished, swallowed by its nocturnal world.
It was 11.15 p.m. on June 11, 2003. Earlier, a Brainfever Bird’s uncharacteristic nocturnal grackle seemed to be reminding us that we
were two hours late. All through an exceptionally long and dry summer, Animish, Shashank, Paritosh and I had waited to take a night
walk in Borivli’s Sanjay Gandhi National Park (SGNP) on the day the monsoons broke in Mumbai.
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A faint drizzle tinged the night with a touch of the ethereal and a thousand-frog orchestra broke out in alto, tenor and bass. Around us, as we
walked along the foot of the Kanheri caves, fireflies flashed signals to potential mates, looking like stars in the firmament. An Indian Nightjar
flitted away into the darkness. Everything was damp. And living. The expression ‘bursting with life’ does no justice to reality. The forest was
literally alive with flying, chewing, crawling, biting, writhing life-forms. And as the old ditty goes: “Everything old was new again!”
Nocturnal and diurnal creatures are differently adapted to exploit opportunities and to overcome threats to their survival. But the stimuli
that trigger their behaviour are the same. Water (rain, in this case), has probably been the most important impetus for plants and animals
from the dawn of life for both worlds – the bright as day and the dark as night.
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Humans (most of us anyway) are diurnal creatures who little understand just how routinely a setting sun switches on ‘the other’ equally intriguing and active world. Over generations, nocturnal organisms evolved ways to counterbalance the absence of light. The dark, in fact, became a weapon of offence… or defence. Some developed acute hearing; snakes developed nerves in their lower jaw to detect the slightest vibration – like the soft footfall of a cockroach. Others accumulated thermal-imaging systems that armies would lust for. Like rock stars on a marquee, a select few – such as a 50 mm. centipede I saw – use bioluminescent secretions to draw attention to or away from themselves. Long, sensitive bristles became the standard, to help tell friend from foe. All creatures had one thing in common – they turned disadvantage (darkness) to advantage.
Amphibian love songs dominated the nightlife of Borivli, the reverberating tak tak of the common tree frog (Polypedates maculatus) and the awang awang of its cousin, the Indian burrowing frog Sphaerotheca breviceps were distinctive. The dainty male P. maculatus we saw hanging precariously from a twig over a small pool, was relatively silent, waiting for the chance to grab a willing female and weave a foamy egg pouch from where their progeny, tadpoles, could fall towards their destiny in the watery world below. The squelchy mulch over which we walked was fast becoming a veritable soup of decaying vegetation, uneaten animal parts, excreta, soil and water.
Burrowing frogs had secured vantage points around breeding pools to woo passing females. Some males bellowed their availability; others were in advanced stages of matrimonial embrace.
We moved on. Almost every large boulder sported a Brook’s house gecko Hemidactylus brookii. A gorgeous juvenile spotted gecko (Hemidactylus maculatus) clung to a cement culvert. With almond-coloured bands on a creamish background, this reptile might grow to a whopping 25 cm., eating insects, spiders, scorpions and other geckos with equal facility!
My light picked up a freshwater crab Paratelphusa (Barytelphusa) sp. All summer long, it had dug itself deep into the soil to escape desiccation. Just 12 hours of rain and, together with thousands of compatriots, it had emerged to forage, fight and produce millions of young crabs that would virtually engulf the forest floor in the months ahead.
“Stop!” whispered Shashank. It was a Travancore wolf snake (Lycodon travancoricus), the less common of the two species of wolf snakes found in SGNP. The black and yellowish-white snake was as good an example of Batesian mimicry as you could hope to find – where an innocuous animal resembles a highly dangerous species – in this case, the common krait Bungarus caeruleus.
Kill or be killed. Hunt or be hunted. Eat or be eaten. Contrary to what most people imagine, the natural world is not a blissful, calm and peaceful place. It is a bloody battlefield. Camera in tow, I gorged my curiosity on the sight before me – a wolf spider (Family Lycosidae) with extraordinarily reflective eyes. The tapetum, a layer of reflective cells amplified light that hit the retina causing it to glitter under my head-lamp, even at a distance of 15 m.! Wolf spiders time the arrival of their spiderlings with the monsoon when food is abundant. As I cast my gaze about, I saw the forest floor glittering with countless eyes – wolf spider mothers carrying 70 to 90 spiderlings each on their backs! Before their mother’s maternal affections are replaced by her normal predatory instincts, the young would dismount and go their separate ways!
We spotted a pair of fungoid frogs (Rana malabarica), rust-coloured with a sprinkling of white on their black flanks and legs. Exquisite! How many wolf spiders had they eaten? And did they know about the impending rain before it arrived, or only when the water touched them?
“This is a lesson on food chains!” I joked as we almost stumbled upon yet another nocturnal reptile, the bamboo pit viper (Trimeresurus gramineus). This one has a penchant for warm-blooded animals, but geckos and frogs are also acceptable. It perches on exposed roots or low-lying branches waiting for its thermo-receptors to kick in and detect heat from unwary rodents. It spends its days in burrows on
earthen banks rather than on trees.
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By the time we reached the northern side of the caves, just two kilometres away, six hours had passed. The sun had already started to lighten the edges of the forest. We were bone weary, wet and very happy. For every creature we saw, we knew that a thousand had escaped us. Not five kilometres from where we stood, the city was coming to life. I would be able to catch a few hours of sleep before rushing to the Sanctuary office to pen down my experiences of the night.
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