The flying dragons of the hill forests of South India don’t proclaim their presence with fanfare. Instead, they stay hidden from predators, virtually indistinguishable from the lichen-speckled tree-trunk homes. To be airworthy, they are as diminutive as articulated action figures. Instead of beating wings that can power flight, a colourful flap of skin stretched over an elongated rib cage acts like a sailcloth. In scientific parlance, it’s called patagium, meaning ‘gold edging of a woman’s tunic’. As hand gliders leap off a hilltop, the lizards dive off a tree to glide to another. When they land, the ‘sail’ settles against their bodies, allowing them to scurry up and down tree trunks.
Special audience
Besides these fantastic flying appendages, the males of the species possess a long foldable lemon-yellow ‘beard’. They flash these dewlaps by extending and retracting them rapidly in silent communication with others of their kind. At quiet periods, they tuck these dewlaps against their throats.
Many lizard species bob their heads and perform push-ups to threaten their rivals. In dark dense forests, these messages can go unnoticed. These dewlap-flags evolved between 30 and 50 million years ago to catch the attention of the nodding dragons’ audience. The lizards seek sunny spots where the light makes their translucent fans more conspicuous. Since they flash their long throat flaps at the slightest provocation and glide from tree to tree in pursuit of rivals or mates, they hog researchers’ attention.
Although females are larger than males, their dewlaps are tiny nubs. Do females communicate by flourishing their throat flags? Masters’ student Avantika Sharma from Nainital wanted to know. She enquired with experts, read everything written about the species and found surprisingly little. She’d have to find the answers herself.
Hectic schedule
Some researchers stay awake all night to observe nocturnal species, and others conceal themselves in hides before dawn. The schedule of flying lizards makes the job of studying them easier. The dragons wake up at 8 a.m. and, as the sun glinting through the canopy warms them up, they zip through their business until noon. They take a midday break and resume feasting on ants after 3 p.m. Long before sunset, they retire. It also helps that the dragons thrive in arecanut and coconut plantations along the Western Ghats, where they are much more visible.
While the dragons kept convenient hours, catching them proved to be more of a trial. Sharma needed a pole that could extend to the higher reaches of palm trees and remain stiff while slipping a noose around the lizards’ necks. PVC pipes didn’t work. As one unsuccessful day followed another, Sharma came close to giving up. Then she tried a 30-ft pole used for picking fruits and caught more than 40 lizards.
With a non-permanent marker pen, Sharma marked each with a number. Every day for four months, she watched and video recorded them, one at a time, in 20-minute spells.
While males were busy courting females and chasing other males, the females were quieter. That changed one day when she spotted two females on the same tree. They demonstrated to each other by dewlap flagging and finally one sent the other gliding off her tree. “That one observation increased my confidence,” says Sharma. “I felt I’d find something interesting about the females of this species.”
Sharma discovered dragons of both sexes send subtle messages from tree to tree by flashing their dewlaps in various ways: fully extending and folding them, performing the same action slowly, rapidly flicking them, and holding them stretched out. Males bob their heads as they approach females, which respond by fluttering their yellow flaps and flicking their tails. They use their entire bodies to telegraph their intent. When the males are at a distance, the females extend their wings fully and arch their backs. They weren’t as passive as other researchers made them out to be. “I was surprised that female ecology and behaviour were neglected and misunderstood,” says Sharma.
What do these signals mean? Answering that would require the researcher to get that fruit-picking pole out again and spend many more months observing the lizards.
These flying dragonssend subtle messages from tree to tree by flashing their dewlaps in various ways: fully extending and folding them, performing the same action slowly, rapidly flicking them, and holding them stretched out
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