A Journey through Wallacea

A journey through Wallacea

Wallacea, just the name makes this sound like an unusual place. But it truly is a remarkable region for so many reasons. Named after the English naturalist Alfred Russell Wallace, who developed the same theory of evolution as Charles Darwin, and by all accounts was a younger, far more thorough and brave man who lived in the wilds of Asia and studied its plants and animals with feverish enthusiasm. He missed out on publishing his theory on time due to a number of reasons, but as Darwin beat him so narrowly, Wallace missed out on all of the credit. Wallace today is hardly remembered. What Wallace did notice was that Australian/New Guinean wildlife and forests stopped abruptly as far east as Lombok, roughly in the middle of Indonesia, and Asian wildlife suddenly took over at Bali, the next island to the west, only a short distance away. The line between the two is known as Wallace’s Line and it neatly divides the two regions – Wallacea is the name for the area immediately around this line. Bali is where this journey begins.

A odd creature in the trees of Wallacea

Wallacea is rich in things that take to the air that normally wouldn't. This is the 'flying lizard'

The Flying Lizard looks like an ordinary dragon

Wallacea truly is an amazing place. The tall trees and forests that exist over much of the area are home to a variety of unusual animals. Particularly interesting is the way many of the sea and tree dwellers get around and escape danger. All of the vertebrate groups have members that get about by air. Other than the obvious birds that take to the air there are many others. Fish, such as the abundant Flying Fish can be seen at sea, while there are gliding Squirrels in the forests that leap from tree to tree with a thin layer of skin between the front and back legs that allows them to glide for considerable distances. Oddly enough, frogs too have a similar technique. Several species of “Flying Frog” have massive parachute-like hands and feet that allow them to execute a controlled glide to safety if a snake or other predator pursues them in the tree tops. Speaking of which, there are even a couple of species of Paradise Tree Snake that glide as well! Ribs that can be expanded in mid-air make the snake almost flat as it glides from the trees to the ground or a distant branch as it uses a typical snake motion throughout the flight

But most commonly seen of all of the gliding animals in Wallacea is the ever present Flying Lizard Draco volans. This is the most common lizard of the daylight hours around Wallacea on the palm trees and in the Frangipannis. Looking much like an ordinary small dragon or iguana they clamber about the branches doing pushups to impress rivals and attract mates. Males have a large yellow “flag” on their chin which can be twitched to signal to other flying lizards. But when danger threatens or when a new tree is to be colonised they will leap off and expand their ribs much like a round disc. This forms kind of a wing which allows them to make a controlled, accurate descent to another tree- and safety.

The chin "flag" is kept folded away most of the time

The chin “flag” is kept folded away most of the time

But when their tree is under threat of invasion by a neighbor out it comes


It was these lizards that were of particular interest to me in Bali. They are not hard to find throughout Wallacea- look carefully in the branches of the trees for these smallish lizards silhouetted against the sky. When the sun is shining they are frequently seen in territorial disputes with neighbors, the males standing tall and revealing their bright yellow chin “flag.”

The lizard showing the now expanded rib extensions it uses to glide

Oh, and they bite!

While finding them in Wallacea is no hard task, actually catching one of these alert little creatures is not simple at all. When spotted, they usually make a dash for higher branches, or quietly slip behind an object. Sometimes they will be so involved in a fight that they come to the ground, where in the grass they are fairly helpless.

But you have to be lucky. I saw one fairly high in a tree and coaxed it down a little with a very long broom. Much to my surprise, it then leapt into the air, expanded its ribs and floated to the ground like a steady leaf. Once on the grass, I picked him up and he made a determined effort to fasten his jaws around my fingers. After some photographs he went back into his tree.

What lurks in the seas of Wallacea?

Walking the beaches of Wallacea, this time Sanur in Bali has also been eye opening. I managed to spot a small head break the surface among some sea grass, so I walked over and much to my delight there was a Little File Snake. I picked him up gently but having no camera with me I was a little disappointed to have to release him, as it was the first I had caught after years of having a careful eye out for them. No problem, as the next day I found three in less than a hundred metres of the beach on low tide. Taking one ashore for pictures was fun, as I had an instant audience. About twenty people wandered over for a look, including a very distressed hotel manager. He was concerned that there was someone showing his guests that there were snakes in the water near his hotel. He asked with a look of genuine fear in his eyes “Is that thing dangerous?” I explained that no it was not, apparently satisfied he walked away. Minutes later some of the guests walked past and informed me that the same manager was having a panic attack back in the hotel! File snakes are represented by three species, the Javan of western Wallacea (Acrochordus javanicus), the Arafura (A. arafurae) and the Little (A. granulatum). The first two are freshwater species, the Javan being found in Western Indonesia and the Arafura being found in northern Australia and southern New Guinea with the Little being mostly found in the shallow coastal seas of Australia and Asia, west of Wallacea all the way to India. All of them have baggy skin which, when they swim forms a keel under their belly. This loose skin gave them the nickname “Elephant’s trunk snakes.” Being totally covered in raspy, conical scales means that they never voluntarily come ashore as their scales are designed for grip, not for effortless sliding over the ground. These remarkable gripping scales are like the surface of a file, hence the name and are used to grip fish they grab and coil around like a python. Each one is tipped with a hair-like structure, apparently used for sensing the motion of nearby fish.

File Snakes are clumsy and helpless on land

But sleek and graceful in the water

One day while walking the beach on a falling tide I decided to look in a little more detail for Sea Kraits. These are well known to locals in Wallacea, but although I had seen loads of File Snakes by this stage I had not seen a single Krait. Apparently they are more common outside the fringing reef behind the surf breakers. Locals did say, however that these reptiles come ashore at night and hide among the rocks. While in the water I noticed a banded tail hanging out of a floating pontoon. Knowing what it was immediately, I carefully held it and lifted it from the water My first Sea Krait! I released it as I had no camera with me, I had left it ashore. I looked under the pontoon, and coiled up among the floats were another five or so! I decided to return at sunset in the hope that there might be more. So, I did and found some that were easier to reach. Carefully taking one ashore for pictures I then returned it to the pontoon to sleep. That’s the thing with Sea Kraits, unlike the closely allied True Sea Snakes, they come ashore whereas true sea snakes stay out at sea, giving birth to live young. Sea Kraits lay eggs on land and return to land every night to sleep. Waiters at one of the beachfront restaurants say that these snakes sometimes come up out of the sea and cross the floor of the Al-fresco dining section among the feet of terrified diners and vanish into the garden.

Sea Kraits, unlike true Sea Snakes come ashore at night…

… and sleep among the rocks.

Don’t try this at home

There are rumours that Sea Kraits and Sea Snakes cannot bite people because their mouths are too small and/or their fangs are in the back of their mouths. Both of these ideas are crap. They are capable of delivering a nasty bite but bites are extremely rare as they are very placid, even when provoked. I handled the two I caught with no problems other than a little hiss. The one I photographed climbed up my arms and I held it like a pet python.

 

 

 

Unfortunately, after taking a bus trip through Lombok, then Sumbawa and on to Flores, I came down with a serious case of Dengue Fever and spent seven days lying down, five of them in hospital. My visa ran out and I had to leave to Malaysia. So, the journey continues in Borneo. Check out the pages and videos related to this fascinating island.

Wallacea will have to wait until my return…

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