Into the Misty Mountains of Borneo

Into the misty mountains of Borneo

My name is Phil Lewis I am a Zoologist from Liverpool England and I have been travelling and living in Australia for over 2 years. On my travels in Kakadu National Park in the Northern Territory late December 2010 I met a like minded naturalist who is now a friend and colleague Nathan Litjens. Nathan told me about an opportunity to spend some time in Borneo, staying with a friend of his and we agreed we should seize the opportunity if and when it came. So in April 2012 he called me telling me he was there and that it was pretty incredible for wildlife particularly herpetofauna. I began making plans to get out there myself and soon after I was jetting over there to meet up with him to spend 2 weeks photographing frogs and reptiles as well as other wildlife we came across. Here is an account of what we found over a 10 day period.

It was the 30th April when I arrived and after a confusing start, him being at one airport terminal and me being at the other he finally picked me up and we headed for his friends apartment Rowan Brown. After a couple of visits to a motorbike garage we got Rowan’s motorbike in good working order.

The giant river frog eats anything it can fit into its mouth!

That night we headed off up the Crocker mountain range with him driving and me on the back. First we stopped at a lowland creek surrounded by partially disturbed lowland rain forest. After seeing several frogs escaping from us we came across the giant river frog Limnonectes leporinus. It was a large frog, this individual was around 120mm although males of this species are known to grow to 175mm. This frog can be found in both primary and disturbed forests in large to medium sized clear or turbid streams. Interestingly males have no vocal sacs and therefore have no advertisement call. It is found right throughout Borneo. Adults grow large enough to feed on crabs and other frogs.

The abundant Kuhl’s creek frog

We carried on up the mountain range for while and stopped at a locality where several frog species were calling. We made our way down a steep and narrow slippery path through old secondary growth forest and stopped to listen to the various species calling near the stream. One species was giving off a loud honking sound and we tried our best to locate it by turning off our lights for a a minute or 2 then trying to pinpoint it once it started again.
Unfortunately we never found out what frog it was even though we were right over where it was calling, once we were too close it just ceased calling altogether. Back over by the stream we came across Kuhl’s creek frog (Limnonectes kuhlii). I soon found out that these frogs were very common and we would come across dozens every night. They live in both primary and old growth secondary forests from sea level to 1600 metres. They prefer small to medium sized clear streams never venturing no more than a few metres away from them. Although very common, when living in areas with a high density of giant river frogs they tend to be rare due to being preyed upon by the latter species. Known from all parts of Borneo it also occurs through most of South East Asia.

The spiny slender toad!

Immediately above the stream around head height on the bank were a pair of spiny slender toads Ansonia spinulifer as well as a couple more lone individuals near by. These are one of the strangest toads I had ever seen, first of all they are great climbers being found around waist or chest height perched on plants or shrubs always along fast flowing streams which is unusual for most species of toad. Secondly every wart on the toads body ends with particularly pointy spine, it also has a very slender body. They are found in all parts of Borneo in hilly lowland forest below 700 metres.

The file eared tree frog

Heading further up the mountain on the motorbike we spotted a huge tree frog on the road so we turned around and I cupped it in my hands. A few seconds later we saw a different species of tree frog also in the road so I managed to get that too. We stopped to photograph them both and what a treat the first one was. It was a file eared tree frog Polypedates otilophus one of the most spectacular tree frogs I had ever seen! It was huge and bright yellow with a saw-edged bony ridge running over its ear drum.

When I smelt my hand there was a distinctive musty stench rather like the smell of a frog or a lizard which has been dead for several days. I wasn’t expecting this from such a beautiful looking frog but this is a great survival technique, after all what animal wants to eat spoiled food? A monitor lizard maybe but not much else. This frog can be found in both primary and disturbed forests and also in plantations. Adults feed on large insects, particularly large tree crickets. Then Nathan opened the bag he had put the second frog in while we had been taking photographs and the second frog leaped out and bounded across the road none stop until it leaped over the road barrier and down a fairly steep sloping embankment, certainly too steep for us to go after it but fine for the frog. We were sure it was the golden tree frog Polypedates leucomystax.

We continued to climb the mountain winding up the road on the motorbike. At approximately 800 metres we stopped at a flooded drain to check out a population of litter frogs. This species was the slender painted litter frog Leptolalax pictus. Apparently this frog is never found at low elevations usually only seen between 500 – 1540 metres. Further up the mountain still we stopped at another drain which had a big retaining wall on one side of it shaped like giant steps. We heard a fair bit of frog activity coming from there so we stopped to check it out.

Only found in Western Sabah, Rhacophorus anguilirostrus is a frog of high altitude forests.

After 5-10 minutes Nathan located a masked tree frog Rhacophorus anguilirostris which repeatedly leapt into the rainwater drain every time we tried to position it on a leaf for photographs but after some time and a lot of patience we finally got it to keep still. This frog is known only from the mountains of western Sabah.

The glow worm – actually a beetle larva this time

We eventually reached the summit at 1300 metres being right up in the cloud forest. Unlike the hot and sticky lowlands it was cold and foggy at this elevation and felt especially cold when we were driving on the motorbike. We got off the bike and began to explore a near by stream. We seen a pretty large glow worm and got some night photo’s of it. We began to climb the lush cloud forest stream. We were on the look out for particular frog called the montane horned frog Megophrys kobayshii and after 20 minutes Nathan spotted large eye shine several metres up on a steep bank.

Montane horned frogs are very spectacular

To my delight it was a montane horned frog just sitting amongst the leaf litter. I was ecstatic! I was really looking forward to seeing one of these as I have always been familiar with the similar lowland species of horned frog. This thing was huge about the size of your hand. The fleshy projections above the eye make excellent camouflage helping it to blend in with the leaf litter. They even have ridges running down their back which look like detailed veins in leaves; truly a master of camouflage. They are only known from high elevations from 1230 – 1675 metres.

Look at that glare!

So far only known from the mountainous parts of western Sabah from Mount Kinabalu through the Crocker range. It was the find of the night! Huge anurans like this one have always been a favourite of mine. After several photographs I reluctantly placed it back in the leaf litter, I could have spent all night looking at it. Nath then brought my attention to a montane litter frog Leptobrachium montanum. These frogs look so strange they really are all head!


The montane litter frog

The head is huge around one third to half its body length enabling it to tackle large prey. This highland form is found in submontane and montane forests above 900 metres.Lastly as we got out of the stream and back onto the road we spotted a Whiteheads torrent frog Meristogenys whiteheadi sitting in some vegetation on the road side. This medium to large species of frog we would see many times over during the trip; there are plenty of them about. They have very long hind legs capable of powerful jumps.

Torrent frog. These are always found near running water.

On the second night we jumped back on the motorbike and headed back up into the mountains. At around 800 meteres we stopped to observe lots of frog calls. Unfortunately most of it was coming from too high up in the canopy or high up on steep banks. Particularly frustrating was hearing the green bush frog Philautus bunitus; a frog I particularly wanted to see that was far too high up. Nathan had managed to track one down and photograph it before I got to Borneo and I was hoping we would see another, and although we heard many of them calling at different locations it was not to be.

The golden legged bush frog has a beautiful call

We stopped a little further on and went for a walk up a rainforest steam after crossing a rather hazardous and slippery wooden platform and found a golden legged bush frog Philautus aurantium. This species is so far known only from western Sabah in primary or selectively logged forests from 750 – 1040 metres above sea level. Males can be found calling from the leaves of trees and shrubs from 0.5 – 3 metres. We got back on the motorbike and proceeded to our final destination Tambunan. This part of the mountain range was amazing. We parked the bike next to a nice jungle lodge run by a friend and crossed a bridge to begin exploring the forest. Straight away I was blown away by the size of some of these primary trees some of them were 3 -5 metres in diameter!

What a find! The long exposure gives the illusion of green smoke from the animal moving after the flash was fired.

We found a huge female fire fly crawling about in the leaf litter, it looked so strange with its big plated armour and its greenish yellow glow coming from its rear. It looks more like a larvae than an adult. The males are able to fly glowing in the forest. I tried to get some night photographs of it but it wouldn’t keep still. In the same area we heard the strangest frog call coming from the leaf litter but were unable to locate it. Several minutes later a sticky frog appeared on the path. It was a Kalophrynusof sorts but we were unable to identify it to species level as it simply just did not fit the descriptions of the species in that genus mentioned in the field guide we had.

Tequila sunrise frog

Nathan had earlier gave it the name of “tequila sunrise frog” which was appropriate given the bright red colouration. We have since found out it is an unidentified species. It was truly one of the most amazing coloured frogs either of us had ever seen, as well as the red colouration they have small little spines with white tips along the flanks. This genus of frogs produce a glue like mucus when seized by a predator such as a snake and is so sticky it is capable of gluing the snakes mouth shut!

The lowland litter frog in the rare standing pose

Further into the forest we spotted a juvenile lowland litter frog (Leptobrachium abbotti) which is similar to the montane litter frog it has a broad head and bulging eyes. This was the only one I was ever able to get a photograph of sitting up, every other one during the trip would crouch down as per the picture and try to pretend it wasn’t there rather than try to jump away whenever I approached- they rely solely on camouflage as defense. Right after that I noticed a juvenile Bornean horned frog and the fleshy projections coming from above its eyes were even sharper than in the adults.


Who ever thought crabs would live in trees or bamboo?

Nathan then spotted another sticky frog which was even brighter red than the previous one, bigger too. Shortly after Nathan called me over to take a look inside a bamboo internode which was flooded with water and had an arboreal crab living in it! It seamed like the least likely place in which to find a crab as it stood nearly 2 meters high. The night went on like this one thing after the next, more littler frogs, more sticky frogs and every so often a species I had never seen before would appear such as the saffron bellied frog Chaperina fusca which actually reminded me of a poison dart from from South America with its small size and bright colours particularly underneath.

Saffron bellied frog

Short nosed tree frog

The next new species for me was a short nosed tree frog Rhacophorus gauni sitting chest height on a leaf. Nathan pointed out a pile of boulders on the edge of the stream were he had seen a cobra disappear into the week before. We stayed closer to the stream for a while lighting up the vegetation with our head lamps and came across several green spotted rock frogs Staurois tuberilinguis on the leaves above the stream. The stream came to an area where you had to climb up it to go further and there was a small waterfall at the start of the climb, incredibly there was a long-fingered slender toad Ansonia longidigita perched on the thinnest twig directly above the noisy waterfall calling! I took my boots off and stepped into the fairly deep pool below to get a good shot which I had to do fast as the spray and the splashing was going all over my camera. After putting my boots back on we climbed up the waterfall and reached a small dam, there were a few frogs about mostly Meristogenys whiteheadi perched 0.5 meters off the ground on leaves.

Long fingered slender toad

Green spotted rock frog

The dwarf slender toad

Heading back down stream we stopped to look at more green spotted rock frogs when I noticed a small toad, on closer inspection it was one I hadn’t seen before – a dwarf slender toad Ansonia minuta. It was tiny measuring approximately 20mm and this is fully grown for this species! We stopped to photograph it but unfortunately after me only taking one shot it escaped and we couldn’t find it amongst the leaf litter. Fortunately Nathan spotted another one further down stream and we got some good shots. We then headed back into the forest and it wasn’t long before something new turned up. Nathan spotted eye shine from high up on a bamboo cane approximately 6 meters high, at first he thought it was a big gecko but it was a big tree frog. He maneuvered the bamboo lowering it so I could reach it but then the frog leaped and disappeared into the under growth. I thought we had lost it for sure until I seen it sitting spread out on the ground so I reached down and grabbed it.

Black eared tree frog

I was impressed it was a pretty huge black eared tree frog Polypedates macrotis about 80mm in length which would have meant that this particular individual was a female as the males only reach 45-57mm. After getting some good shots of it we let it go about its business. Leaving the forest we jumped back onto the motorbike and headed off for the 2 hr drive home. Along the way we stopped at a drain which had a series of retaining walls forming what looked like a huge steps.

We spotted an adult Bornean horned frog (Megophrys nasuta) about half way up the steps.

Gecko – Cyrtodactylus sp.

I got a few shots of it sitting naturally amongst the rocks. I then moved it so I could get in better for some close ups and it bounded off and disappeared, I was livid! I had been waiting to see an adult one of these and was not happy it had escaped after only getting a couple of photo’s, Nathan assured me saying:
Don’t worry they are certainly not rare we will see more of them.”

And so I tried to forget about it. Before we climbed out of the drain we found a gecko clinging to the mossy wall.

The second time we went to Tambunan was a real treat. We seen a lot of the same frogs and toads only different colour and size variations which was interesting enough but half way through the night we came across something we had been on the look out for since we had been searching this mountain range, it was a Pope’s pit viper Trimeresurus popeorum.

These snakes are really hard to spot because firstly, they are bright green like much of the surrounding foliage and secondly they keep extremely still even when approached. They like to sit about a foot or two above the ground wrapped around low lying vegetation waiting in ambush for a frog or a small rodent to come within striking range. They have heat sensing pits which allow it detect warm blooded prey in total darkness and are equipped with a very toxic venom which destroys muscle and tissue. They are found in northern India, south east Asia and parts of Indonesia. Me and Nathan were over the moon to have come across one and it took a while for me to actually get up and carry on through the forest I could have just stared at it for hours!

The gorgeous Pope’s pit viper

Limnonectes palavensis

Also that night we found yet another species of frog which we had not seen before it was a smooth guardian frog Limnonectes palavensis. Luckily Nathan had gone through the field guide we had on frogs before I got to Borneo and had familiarised himself with most of them so we were nearly always able to accurately tick them off by name as we came across them. The males of this species display very similar behaviour to that of another member of its genus Limnonectes finchi by sitting with the eggs after they have been laid by the female in moist leaf litter and then after hatching carrying the immature tadpoles on his back to small rain pools or to quiet isolated pools at the side of streams to complete their development.

An adult Bornean horned frog sitting up in the leaves

Later on we came across the frog I had been so desperately wanting to see again the Bornean horned frog. This time it never escaped after just a few seconds, but stayed still as we got plenty of good shots of it. This really made my night. I had seen these frogs in the odd zoo growing up and always wanted to see one in the wild so this was like a dream come true seeing a wild one up close. Just like the montane horned frog on the first night I was blown away by the size of this thing. It must have been around 120 mm with a huge head! The head is so wide on this species that its width equates to half of the total length of head and body combined.

Shrub dragon

Again I found it hard to pull myself away from it but eventually moved on as it was already well after 3am and we only had a few more hours of darkness.

It was a small forest dragon sleeping that caught our attention next, Nathan had found it sleeping on a branch it was a brown shrub dragon, the exact species still unknown.

Black spotted rock frog

On a different night me and Nathan began exploring a rainforest stream surounded by plantation and found several black spotted rock frogs Staurois natator perched on rocks and branches and even managed to photograph a mating pair. These truly are attractive looking frogs with their bright yellowish green or yellow undersides with an olive green upper surface with black spots. Amazingly the upper surface of the three inner toes and the webbing between them is turqoise blue.

We stumbled upon a water skink perched on a leaf above the stream sleeping. Usually in the day when you see these things you can’t get anywhere near them so this was a rare chance to get up close and get a couple of photographs.

Further up the stream I went to stand on a huge rounded pebble in the middle of the stream and noticed a few things moving on it they looked like either insect larvae or tadpoles. As I bent right down and shone my torch light on them it was indeed tadpoles attaching themselves to the rock with their strong sucking mouth parts in a real fast part of the stream and they were moving against the current it was amazing!

Torrent frog tadpole with untold suction!

Nathan had gone right ahead of me by this stage and so I hurried to catch up with him fearing I was missing out on something new. I turned a corner in the stream and I could see him ahead of me trying to call me over but not wanting to shout to loud so he had obviously found something. That something was the most amazing coloured bird I had ever seen in my life, it was a king fisher and the colours were incredible! It had a bright orange beak, yellow breast, metallic blue patches on its wings, orange around its eyes and metallic pink and blue on its head. It was sleeping 2 meters above the stream on a branch.

Asian bullfrog

Along the stream we saw dozens of other frogs and toads which we had already seen and photographed on different nights. We walked up the stream for at least 2 hours stumbling or jumping from dry spot to dry spot until we decided to make our way back down stream to the bike.

On the way out of the stream just by the road side sitting among the short grass was an Asian bullfrog, so called because of the call they make which is similar to the call of the The American bullfrog, its call sounding similar to that of cattle moaning as though in pain. These are very opportunistic amphibians colonising areas where humans have cleared the forest for settlement and as their were people’s properties opposite the stream we had been, it is no wonder they were about. Strangely they only inhabit such places, you never see them in closed forests.

Hose’s bush frog, look at the lovely green eyes

We headed up the mountain stopping at the same drain from the previous night. Climbing up the steep slope which ran along the step like structures we were on the look out for Hose’s bush frog Philautis hosii as we could hear them calling. Finally Nathan spotted one so I reached over to grab it but it jumped as I went to cup it and escaped into the under growth but we soon got a second chance and this one stayed still as I photographed it. Another species ticked off the list. Further up the steps was another species new to me, it was an Inger’s dwarf frog Ingerana baluensis and I had to get 2 quick shots of it before it disappeared amongst the rocks.

The little known Inger’s Dwarf Frog

On our way home we just let the bike roll down the mountain road keeping a keen eye out for wildlife. When we were near the rainforest stream we had searched earlier we spotted a very special frog in the middle of the road, it was a rock skipper Staurois laptopalmatusand it was very unusual to find one in the middle of the road as the literature says they are only ever seen on rocks in the middle or the side of streams or clinging to rock faces at the edges.

The unusual Rock Skipper

I picked it up off the road and we positioned it on a rock surrounded by cut grass and far enough away from any foliage in which it might like to escape into. As we got our cameras ready it jumped into the darkness, convinced it had headed towards the stream we searched for it pretty far from the rock we had put it on and there was no sign of it. I was gutted as I didn’t even get to have a real good look at it and now it was gone. Then when all hope was lost Nath spotted it just sitting on the other side of the rock we had originally put it on. It had only moved a couple of feet and we were looking for it 5 – 10 meters away! Happily, we took it into the flood drain positioning it on a rock in there so if it tried to escape it would be blocked by the steep walls on either side. After Nath got a few photos of it he went wondering along the meter wide drain which was built to simply direct flood water into the many streams. While I was still photographing it I heard him say…

“Phil, I’ve got a present for you!”

Sticky frogs, Kalophrynus pleurostigma

And in his hand was a sticky frog a Kalophrynus pleurostigma. I was in great spirits what a night it had been 6 species I had never seen before all in one night!


The Bornean white-lipped frog Hylarana raniceps found near a plantation on the mountain side

Juvenile Dring’s slender litter frog Leptolalax dringii

The mahogany frog is found around pools and slow streams in the forests

The tiny white spotted toad (Ansonia albomaculata) was found in the small side stream where we found the rock skipper.

There is never a shortage of crabs in the forest

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