Thanks, guys! These wet walls are a common road- and trailside feature in mountainous areas here in Taiwan. It rains quite a bit here, and the mountains are steep, so these walls are put up (mostly from concrete) to stabilize the slopes, prevent landslides by erosion, and give all that water a controlled path to run. To achieve the latter, there are rows and rows of drainage pipes running from the back/inside of the wall to the front where the water runs down the wall into the road/trailside ditch. After heavy rains, these drainage pipes are very busy, but usually they just carry a trickle - just enough to keep the walls wet, but not too much, so the pipes and walls are always full of frogs which in turn attract snakes.
We're going back to this particular wet wall tonight and will walk its entire length. Can't wait to see what's on tonight

Kraits have become quite a common sight now; we spot them almost every night. Just over three weeks ago I met the first one in my life, and now I've already become so blasé about it that I only photograph the large ones in nice settings

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The day before yesterday we found a young one on the road with its guts hanging out, looking quite dead.....until we touched it with a long instrument. BAM! Instant resurrection and two very fast defense bites. I've been told that a lot of people here get bitten every year because they handle such "DOR" snakes. Another valuable lesson for my kids, to say the least!
monklet, what do you mean by "scalation" in this case?