Thursday, September 9, 2010

Unique adaptation of vine snakes

Adaptation, in its many forms, is the most common phenomenon, and is always survival oriented. Survival is of course, the most crucial game for any animal, a game where losing is not an option, but is often the result.

We humans have come so far is because of our little adaptations; all the ‘out of the box’ experiments. But are we the only ones doing that?

Nope!

Our way of life is very typical, and some animals have noticed that. These animals have now adapted well enough to get a prefix ‘House’ before their names! House sparrows, House crows, House spiders, House ants, House geckos, House rats, House this, House that. Isn’t it smart thinking as opposed to staying away from predators (us)?

Some of most obvious adaptations are witnessed in the urban setting. Monkeys (Langurs and Macaques) raiding kitchens; “stealing” food, Crows and bats catching insects by the street light posts after dark, Black kites living almost exclusively on offal, cockroaches in drainage pipes, spiders in your computer… There are just so many of them.

Pests! What about pests? They are super adaptive, aren’t they?

It is the change in environment that forces the inhabitants to adapt for a better life; after all, losing the game is not an option. The ease of adapting to something is equivalent to smart innovation in human language. But, not every human is smart and it is no different in other animals either. Let’s get to a fresh example of a brand new adaptation and evaluate the smartness!

June 16, 2010
“Whoa! Did you hear that?!?” I said to Akanksha with a big smile. A big smile because I could make a good guess of what was happening!

Anything exciting at midnight is usually fun!

“Something’s caught a frog!” said Akanksha, equally excited now. I was of course proud of her to guess that accurately.

I rushed out with a torch and WHOAAA! This thing was right outside my room! Of all the possible predators, this was leeeast expected. A Common vine snake!!!

“Camera! Camera! Get the camera….. quick”  Fortunately the snake can’t hear me yelling.

Ahaetulla nasuta feeding on Polypedates maculatus

“Wow, that was awesome!”

Croc Bank is an awesome place providing an ideal habitat for a lot of native species. Amidst the shoreline ecology, Croc Bank is a mini semi evergreen forest system with more than 135 native plant species.

It almost stays the same all year round

With over 60 species of birds, 30+ species of herps and some resident and occasional mammals, and tons of invertebrates, the faunal checklist is pretty impressive for a 7 and a half acres area.

So what is the big deal if you see a snake catching a frog?!? Well, the Common vine snake Ahaetulla nasuta is supposed to be a diurnal snake, and the guy we saw was hunting at midnight! Now, that is interesting.

Active herpers would know that Ahaetulla are best spotted at night when they are sleeping / resting in bushes and scrubs. I had never seen or heard of this species actively hunting at night, so I was pretty excited about it. This can’t be a coincidence, can it? 

When I get excited, I get curious too. 

June 18, 2010
A couple of days later, me and Akanksha were returning from Chennai. We had just entered from the Irula Cooperative gate on my motor bike, and saw a vine snake crossing the road.

“Vine snake! Watch out..!” exclaimed Akanksha.

This was at 22:00hrs! There is something more than coincidence here. I was sure.

I must ask someone, and who would be better than the reptile guru himself – Rom Whitaker!

“Hmm, interesting. Good if you share your observations with the ARRS gang as there are tons of  vine snakes there and seem to sleep deeply at night, but who knows?” Rom wrote back.

June 19, 2010
I decided to be on night duty! I might see more if I look for them. The next night, I was roaming around at night, all over the place. Came back after an hour and a half; hot and sweaty.

“Gotta go drink some water. Man, I feel dehydrated.”

I glanced at the planted fence on the South side of the canteen before entering the kitchen for a cold glass of water. Green, green, green, vine snake, green, green….

“I must be really dehydrated!” I was thinking while I was filling up water. Mind’s playing games.. or is it..?

I went back and could see a typical green color. “Oooh man, that IS a vine snake! Super!”

Camera, notepad, pen and I’m ready. Wait a minute.. Now I can see 2 vine snakes.. Damn, should have finished the glass of water. 
No wait... there ARE 2 snakes! Jackpot..! :)

2 vine snakes. Bad picture quality, good timing.

These 2 were typically exploring the area as they do while hunting, carefully scanning the fence and were checking out anything that moved in the wind. Time check: 22:50hrs.

I sat there taking notes for 2 and half hours till they decided to push off, both in opposite directions. This was getting more and more interesting now. So this is not just one snake. There are at least 3; the first one was around 28 inches long, and now these 2; around 40 inches and 34 inches in length.

Is it a trend across the species? Or is it a local adaptation of the resident population?

July 25, 2010
I was still herping out at nights, trying out my luck. I wished I could go out more regularly. Didn’t see anything in the driveway that night. I was on my way back when I just recalled a distinctive similarity in the hunting strategy of those vine snakes. They were all utilizing the artificial lights! Well, except the one I saw on the driveway, but the rest were.

“Oh yes, the first one caught a frog right under a bulb outside our room. Second one was in pitch dark in the driveway, but it was on its way to some place. Third and fourth were again in the fence that was lit up by the lights from canteen!” I said to myself.

“May be I should go back and look around the canteen area”

I was all smiles when I reached canteen. This time, on a low branch of a tree on the North side :)

A nice specimen, around 36 inches long, was scanning the area below it. Amazingly, it didn’t quite get bothered by my presence. I went back to my room to get the camera, notepad and a pen. I knew it was going to be a longish observation, so made myself some coffee. Time check: 23:10hrs.

I sat there taking notes for over an hour until I saw the body language change. It was – ‘Target locked’

I could see a Bark gecko climbing up a tree nearby. The moving gecko just froze 12 inches away from the snake. Then, there  was a looong wait. 17 full minutes.., before it started climbing up again.

I could see the snake getting ready to strike as the gecko went closer.

“8 inches..”

“6 inches..”

“5 inches…”

...and WHOOSH.. A lightning fast strike; bang on target!

Ahaetulla nasuta swallowing a Hemidactylus leschenaultii

Super awesome adaptation by these guys, eh?

But again, we do find several sleeping at night regularly. Like I said earlier, not all of us are smart! :)

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