"The night is dark and full of terrors."

That was what Melisandre said, and it is true, especially if you are a tiny little lizard living in a dark, dense, rain forest. The terrors of the night come in many forms - giant centipedes with strong jaws and potent venom, giant geckos weighing ten times your body weight and capable of crunching your skull with a single bite, heat-seeking pit vipers that climb slowly up a branch, cat snakes with sharp night vision and the ability to track you down from smell alone even in pitch dark, owlets waiting for the slightest movement to pounce on you from above.

A large (~ 25-30 cm long) centipede in Long Island making a meal of an unfortunate bent-toed gecko. These centipedes are voracious predators.  This species is known to cause severe bites and reaches a maximum length of 33 cm (that's 7 cm longer than the Guinness Record holding species from South America)

When giant centipedes such as the one shown above can make short work of you, you have to be alert even while sleeping. Bay Island forest lizards almost always sleep facing the main stem of the plant - may be they can spot approaching danger better in this position.

 When you are a small (7-8 g) agamid lizard in a rain forest, pretty much anything larger than you is danger. Bay Island forest lizards have excellent day light vision. Their typical hunting strategy is to sit on a tree trunk or twig all day long, watching the forest floor for any sign of movement of an insect. The moment they spot one, the lizard sprints at the insect and grabs it. I once saw a Bay Island forest lizard jump from a tree trunk to catch a little wasp that was sitting on a leaf of a neighbouring plant, which he did in mid jump. Their alertness and visual capabilities allow them to escape predators during the day. Once, in Long Island (a small Island close to Middle Andaman, not New York), I came across one of these little guys running from a green bronzeback (Dendrelaphis andamanensis). Both parties ran across the road, probably without noticing me, but as soon as the snake saw me, it abandoned the chase. We have no idea how good their vision is at night, but many terrestrial animals with excellent day light vision do not have good night vision, and this seems to be the case with Bay Island forest lizards too. As soon as night falls, these lizards climb up to their favourite nighttime perch, a delicate branch or leaf, and settle in.

A long, thin Andaman cat snake, capable of climbing up the thinnest branches. Cat snakes have large eyes giving them good night vision, but it is the forked tongue that smells down stationary prey. Slight vibrations from its movement may be the only clue about approaching danger for the lizards.

Andaman scops-owl, a potential nocturnal predator

 In our recently published study, we explored this behaviour in two sympatric species, the Bay Island forest lizard and the short-tailed forest lizard, in the Andaman Islands. These two species take sympatry to extremes: one can often see both species sitting side-by-side on the same tree trunk. When it was time to sleep, both species seemed to prefer similar looking perches: a horizontal leaf or delicate branch, making us wonder why! We also thought that since the two species are very similar, there might be some sort of niche partitioning, perhaps sleeping microhabitat. We found that the larger the lizard, the higher its sleeping perch tended to be. The larger of the two species, Bay Island forest lizard (Coryphophylax subcristatus), tended to sleep on higher and outward branches of plants. Other than that, surprisingly, the two species did not seem to differ in their choice of sleeping sites and there seemed to be little evidence for these two species competing for sleeping perches. Even more surprising was that most of the lizards (74% C. subcristatus and 90.98% C. brevicaudus) slept with their head pointed towards the main body of the plant, and almost always on a delicate, unstable, horizontal perches. This was in sharp contrast to their diurnal behaviour: most of the time, one would find these lizards perched vertically on a tree trunk. Could this selection of sleeping perch and position be because they are better able to detect a snake or a centipede approaching from the same plant? 

However, this opens up another question: do these exposed perches make them easy targets for nocturnal raptors? We do not have any clear answers for this question. One possibility is that owlets and owls, which use primarily visual and auditory clues, may have a harder time detecting sleeping lizards as long as the lizards do not move. This would mean that most predation at night comes from predators such as snakes, centipedes, shrews, etc that can detect a sleeping lizard based on smell alone. If this is indeed the case, sleeping on exposed, unstable, branches or leaves, away from other vegetation is a good choice.

This behaviour of sleeping on thin, isolated branches and leaves is not restricted to Bay Island forest lizards. Elsewhere, I have seen other diurnal agamids such as long-tailed agamas (Bronchocela sp.), Oriental garden lizards (Calotes versicolor), blue-throated lizards (Ptyctolaemus gularis) doing the same. In most cases, they sleep with their head oriented towards the plant and tail hanging out from the distal end of the branch or leaf. On the other side of the world, there are studies on Anolis lizards exhibiting near identical behaviour, perhaps a case of convergent evolution of behavioural strategies as a response to similar selection pressures.

Girl on top: a female Coryphophylax in the Nicobar Islands decided to sleep with her hind-quarters on a male's head.

So, have we answered all questions? Do we really know why they do the things they do? Nope, we haven't even scratched the surface yet.

Flaming red tail

 

A juvenile Dussumier's litter skink I photographed in 2009.

 

"Arana" (Malayalam for skink) was one of the very first reptiles I identified around my house. In most other parts of peninsular India,  a common skink would most probably  be a Brahminy skink (Eutropis carinata), a much larger and less colourful species. But for me as a kid, the vernacular name Arana always referred to a small skink with bright orange-red tail.

Scientifically called Sphenomorphus dussumieri (Dussumier's litter skink), they were common around my house, giving me ample opportunities to observe them. They are alert, but curious little creatures. They would often come to investigate if some one was doing something in the yard, like  watering the plants. My brother once even managed to feed them cooked rice!

The days have been somewhat hot and dry. I have been seeing one of these small skinks living among the flower pots in our tiny garden. Today morning, I decided to try to get some photos of that one. As I was photographing, I noticed that it was sucking the sap out of a broken branch of a small Elephant's ear plant (Colocasia sp.). It kept on sucking for about half a minute before getting out of the hot sun. I've seen them drinking water eagerly from leaves after I water the plants in the evening during summer months, but this is the first time that I saw one drinking the sap from a plant.

Dussumier's litter skink after drinking sap from the plant. I couldn't capture it in the act, as by the time I got the camera, it was done drinking.

Travel Diaries: Munnar, January 2016

Munnar is a place close to my heart, having spent a year there as a 10 year old. That was a long time ago, and things have changed much, both in my life and for the place. I have visited the area every few years, and each time witnessed the ‘development’ of human greed slowly defacing the landscape. Still, the place has a charm and that’s why we decided to meet our friend there and go birding.

 

Kerala laughing thrush at Eravikulam National Park. These birds were near the information center
and showed no fear of people.

 

When we visited the place last year, we stayed at a homestay in ‘2^nd mile’ (places in the hills are often named like this) called “Estate Residency”. We liked this place because it was relatively cheap (by hill station standards), was away from the town, and most importantly offered birding and herping opportunities within their own cardamom plantation as well as the stretch of road going towards Adimali.

Here are some photos from the trip.

Morning view from our just outside our homestay.

Silk Cotton tree in the light of the setting sun. This tree close to Karadippara was in full bloom.

Although it looks like the canopy of a rain forest, these are mostly cardamom plantations. Cardamom being a shade loving plant, requires a dense canopy and rainforest tree species are allowed to grow in these plantations.

In a cardamom plantation. This plantation is owned by the same person who runs the homestay
and this is a fairly good area for birding. We saw more than fifty species in the plantation itself.

A scimitar babbler  in cardamom plantation, trying to hide from us.

Waterfall near Njamakkaadu junction

Shola forests and grasslands of Eravikulam National Park.

Eravikulam National Park, at least within the tourism zone at Rajamala, is characterized by steep
rocky slopes, shola forests, and grasslands. At lower elevations outside the park boundaries, the
land is covered in tea, coffee, and Eucalyptus plantations as well as human settlements.

A Black Eagle soaring above the shola grasslands of Eravikulam National Park.

The star of Eravikulam National Park, a Nilgiri Tahr quenching thirst. This is one of the few
places on earth where this highly endangered mountain goats can be seen at close quarters.

Eravikulam National Park gets thousands of visitors every day during the holiday season.
Still, the park managers seem to have done a good job of reducing the disturbances by tourists.
There were watchers everywhere keeping a close eye on the activities of visitors, in particular
making sure that they walk only on the road.

A Malabar Giant Squirrel nibbling on a fruit.

Nilgiri Blue Flycatcher. This particular individual was one of the most camera happy birds that I have seen.

A baby Elliot's Forest Lizard. We saw a few of these guys in vegetation along the side of
roads passing through cardamom plantations in Munnar.

One more morning of mist before leaving Munnar.