Woo-hoo! HerpNation actually asked me to write a blog piece for them, and here's the result:

HERPING IN THE TROPICS – ECSTASY OR NIGHTMARE?

Discuss!

I enjoyed it, Hans!
Great mix of photos and text. It was a very nice intro, and I am curious to see where it goes.
That was cool that you got Alex in on the 'conversation' as well.

Looking forward to more
--Berkeley

Loved it!

Great piece Hans and very interesting discussion regarding species/specimen distribution in the tropics. One question I've posed here before but don't recall the reponse is, "Are there burrowing animals which create underground networks of tunnels such as rodents to in the temperate regions?".

Thanks Hans. Very interesting. Sometimes when you think you are in Snakeville, all your dreams come crashing down. I know the feeling. Keep us updated. I particularly like the vipers.

David and Suzanne

Interesting article. I have read that it is similar in the Amazon-basically it's hot as hell all the time, so the snakes have no use for basking out in the open.

Very interesting read, Hans! I am having the same experience in the subtropics, without the benefit of hot weather all year round.. I have also found flipping to be futile, though I still can't resist the urge somehow. =S

Good article. Wonderful writing. I hope your frustrations pay off and you start finding more snakes, and more species.

Hi Hans,

Very nice, I couldn't have put it all better, let alone that your style of writing is simply fantastic. I'm telling you, after 11 years in Singapore (for those who don't know, is a small island of the coast of Malaysia), a few hours flight from Kuching, I have yet to flip something with a herp under it. No kidding, I haven't found any proper animals under cover, let alone one brahimny blind snake (which is pretty pointless, I could go to Hawaii for that), ants and spiders.

Note that there is one general exception to the Fundamental Herping Theory of the Tropics. Mangroves tend to be rich in mangrove-bound species like the what-you-might-call-it bokadam-dogface. Probably this is the result of fewer niches in mangroves (more like temeprate regions in that sense) as opposed to lowland rainforests, and obviously diet. These snakes feed largely on fish and mudskippers which are abundant in mangrove areas. Again, there are still species, even in mangroves, that remain rare, or should I say common?

Hi all,

thank you for your kind words, everyone! I always get real nervous when a text of mine is published that, as opposed to my usual comedy fluff pieces, is actually supposed to be of some scientific value (not that there are many of those texts, thank lawdy...)


And the reason for that is the same as for why there are no snakes basking in the open: it's just too darn-tootin' hot. Who wants to sit under some badly ventilated rock all day at these temps? (By the way, AFAIK, larger snakes do bask after meals, even down here. The usual temperature in the shade does not seem to be sufficiently digestion-driving)


Don't get me started on those. There are even places where you can watch Cerberus rynchops while enjoying a twelve-course Chinese seafood extravaganza. But I have yet to catch one of the little ^%$#@!!s. No fair!

Uhh.....beats the hell out of me. ANYONE? But I wouldn't think so, because for that, I would imagine, you'd need a great number of specimens to upkeep the burrows. And that brings us to back to Square One.


I asked him for advice before I started. Without him, there wouldn't have been an article in the first place. His quotes carry the piece!

By the way: I had (crab) dinner with Neil Das last week, and he let me in on another piece to the puzzle: Dearth Of Arthropods. According to one theory, the leaf litter in the South-East Asian rainforest is the thinnest of them all, thinner than in tropical Africa, and much thinner than in the Amazon. This may lead to a paucity of arthropods, which again leads to fewer specimens of arthropod-eating species. So few, indeed, that in some areas of Borneo, a two-year survey may come up with one single specimen for an entire herp species. But never fret, - worthier heads have ached over the problem: the question why the fabled biodiversity in such places stays mainly invisible is cause for many international debates, papers and drunken brawls in life science departments, and the answer is still very far from appearing any clearer.

I also learned another term from Neil: "structural complexity". That's the godawful mess a rainforest is, and will henceforth replace in my more learned treatises the expression "too damn many hidey-holes".

Gotta go, clear my head by cruising in the krait swamps for a few hours. Maybe I'll finally manage to catch one of those dogfaces...

My experience after having some of the same frustrations in Thailand is that the tropics just have such ideal habitat everywhere, it's too difficult to narrow down exactly where a creature will be. In a dry climate you can search for the moist spots, in a cool climate you can search for the warm spots. But when everything is is warm and moist, a snake could be anywhere, and it's quite difficult to narrow down where they actually are. On top of that, the "anywhere" can include deep within water vegetation, in the treetops, or other spots that might be unlikely under different conditions.

I wasn't able to herp Bangkok constantly, but in getting out once or twice a week I often would have been overjoyed with 10-snake months. I had several 1 or 2 snake months during the drier season, though in prime conditions I also had two 7-snake days (counting blind snakes, of course - not counting brahminy blinds I could brag about 4-snake days at most).





While Bangkok was tough, it definitely wasn't at the extreme that Kuching and Singapore appear to be in that respect. I rarely got out of the city and didn't have transportation, but just looking in local parks and empty lots, this is what I found under cover via flipping:

Within Bangkok:

3 White-headed Blind Snakes - under logs and a rock
20+ Brahminy Blind Snakes - under everything
3 Red-tailed Pipe Snakes - under AC and a log
1 Sunbeam Snake - under AC
1 yellow-spotted keelback - under AC
1 Copperhead Racer - under concrete
3 Banded Kukri Snakes - under logs
1 Striped Kukri Snake - under log
TMTC geckos (spinytail house geckos, Sri Lankan house geckos, and stump-toed geckos)
TMTC skinks (bowring's supple skinks, short-limbed supple skinks, and common sun skinks)
TMTC microhylids (Asian painted frogs, ornate narrowmouth frogs, and inornate froglets)
TMTC Asian grass frogs
TMTC common Indian toads



Outside Bangkok I've flipped those same frogs and lizards, as well as:

3 Yellow-bellied Water Snakes - under rocks in or near water
2 Collared Reed Snakes - under logs
7-8 Siamese leaf-toed geckos
1 Cardamon slender-toed gecko
5-6 speckled forest skinks
1 long-tailed sun skink
TMTC sapgreen stream frogs



So is Bangkok just far enough north that it's not subject to the "super-tropic" effect that makes it so hard to find stuff under cover in Singapore, Malaysia, and Indonesia?

I think the fact that the dense rain forest is blocking out most of the sunlight is largely responsible for the low density of snakes.

Go to areas on the edge of the rain forest and you will likely find more snakes.

Or, chop a tree down and see the snakes that were basking in the sun near the top of the canopy.

Interesting that you found a lot of snakes under cover. I have only ever found two under cover, but in those places there were no other available hiding spots. Even though I'm in the southern subtropics, the karst terrain and forest creates innumerable amounts of hiding spots.. They also seem to be very particular about the weather. We have clear dry and rainy seasons and a short winter. I know that there is actually quite a high snake density here. VERY frustrating..

Also, what time of day have you found the most snakes (anyone feel free to chime in)?

In Kolkata, which I believe is more your zone, I flipped two snakes in three half-days of searching - a wolf snake (rock) and a checkered keelback (ac). Maybe it's an urban thing - easier to find because there's less available habitat? Though the stuff I flipped outside of Bangkok wasn't urban.

The weather is definitely a massive difference. I didn't see a single snake in Bangkok between mid-December and the final day of February (our cool dry season), and two trips outside Bangkok during that time, with my best effort herping, I only found 3 yellow-bellied water snakes and a brahminy blind, all under rocks.





For some reason I found a lot of snakes right around noon. That includes both flipped snakes and active snakes. I think that might have been just sampling error - I kept seeming to be in the best spots at about that time. But the best time for me was probably around dusk and into the early night. And even though I expected stuff to be active during that time, I still kept flipping, and 6 of my flipped snakes were flipped at night (the 3 yellow-bellied water snakes, a red-tailed pipe snake, a sunbeam snake, and a brahminy blind).

Yep, i believe it all has to do with the concept of specialist and generalist species. Typically its the generalist species that occur in more disturbed areas, produce many off-spring, and thrive in higher densities due to effectively less competition with other species in their relatively uniform habitats. They are not your typical extreme of r-strategist species. Many species that tolerate urban areas, scrubland and young secondary forest in SE Asia, are simply generalist in terms of their diet, but can exist anywhere from primary forest to urban areas (good example is a reticulated python). Why is this the case? Tropical islands like Singapore and Borneo and Indonesian islands (and so on) are effectively not very diverse in habitat types (a generalisation but still quiet appropriate), at least if we exlude high altitudal regions. In the past, most of these areas would have been covered in: Tropical (lowland) rainforest, coastal forest, and mangrove. Correct me if I am wrong, but in many areas scrubland is not a very natural habitat type - it is the result of overgrown farmland and past deforestation (i.e. all by people). Now, certain species like the reticulated python already feed on a diverse number of animals - squirrels, rats, monkeys etc. Hence, these scrublands provide excellent habitat for certain grasses, insects, and various mammals that feed on them like some species of rats. However, not all species can tolerate these habitats. Effectively, the animals are introduced to a habitat in which they can thrive with little or no competition. This attracts other species with a generalist diet, such as the reticulated python. Are these going to be more abundant in these disturbed habitats then in primary forest? I believe they are - there is simply less competition with other species for the same kinds of prey, as well as less predation by large animals (e.g. birds of prey) that may not all be able to tolerate disturbed habitats. Does this mean that in the middle of a scrubland you are going to find bucket loads of retics? I believe not - it is TOO hot as Hans commented; another limiting factor. They need hiding places (the snakes). These hiding places are 'cool-down' places, not pieces of cover in the tropical sun, but rather small forested patches. This ideally suggests that snakes may be more abundant near the forest edge as another member commented. What is the problem with this? At least here in Singapore there are very few relatively appropriate (mature) forests surrounded by scrubland that is not bordering a large road. Past-overcultivated areas with scrubland and young secondary forest are not good either - 'all' snakes have been killed here by locals! What this leaves us with - herping in the forest.

Does this always work? Well, the thing is that there are many hiding places yet there arent any hiding places. What I mean by this extremely non-confusing quote is that most cover exists as leaf-litter rather than nice pieces of wood, large easily-turned-over logs, and rocks. Now, most terrestrial species in Singapore have adapted to the way of life in rainforests (after all, as said before, this used to be THE dominant habitat type on the island). Most are fossorial - they live in the leaf-litter or underground. How many of us go herping with a rake and a spade? Exactly... I'd like to suggest that slight variations in habitat due to geographgical location may, in response, result in a slight variation in ecological niche of a species. Potentially, many landscapes in Thailand offer slightly different alternatives then just endless leaf-litter. For example, with the parks that were mentioned i assume relatively disturbed habitat aswell with little natural cover. Clearly, to feel secure, any snakes will hide under any available cover in these cases. But, also, I'm not sure, but maybe the rainforest in Thailand offers a slightly different geographical landscape that gives way for a slightly different niche, yet for snakes that we consider to be of the same species.

DavidG, uh, like, wow. Thanks for those insights! Looks like you'll have to write the follow-up blog post


They don't need sunlight all the time, only for basking. And you'll find plenty of basking spots in the rain forest. There's lots of terrestrial skinks there, too.


True, but I think that's just because you'll always find more of everything in interface areas.


Jonathan, AFAIK, Bangkok has distinctive seasons. There are no seasons here. True, it rains more than usual in the "rainy season", and it's about three to four degrees cooler on average (read: 29C instead of 33C), but apart from that, it's the same all year round.


Alex Krohn once publicly wondered why in a climate approaching 100% humidity, you'll still find most of the animals close to bodies of water. Well, as that field guide to the reptiles of Singapore says, "if it's wet, look in dry spots, if it's dry, look in wet spots." So there IS hope.

this entry makes me want to skip borneo and go to taiwan instead

You would miss out on over 30% of the world's phasmids, though. And the edible fruit of Durio zibethinus!

This topic makes me feel a lot better about myself. I've spent roughly 11 months in SE Asia over the years and didn't find that many snakes. My only exception was in Baluran NP where I found 11 Lesser Sunda White-lipped Pit Vipers on a 2k walk on the road. Thanks,




Curtis

On the other hand, if you live here long enough, they'll come to you. I just found a juvie Coleognathus flavolineatus under my dining table this morning. And no, it hadn't fallen out of my snake bags or anything

Pix to follow

Very interesting thread, I haven't the mental energy to contribute much to it right now, although as usual I find my inner skeptic jumping up and down

One thing I will say is that I wouldn't call the herping in Singapore "tough" - I caught 7 species of snake in my own backyard whilst living there and enjoyed many days where I saw several or more snakes. As has been commented, in the mangroves the snake density is very high (at least the snakes are very conspicuous) - on one particularly successful night I saw over 30 individual snakes of 5 species (never did get to see Cantoria violacea though).

My personal feeling is that "structural complexity" is the reason it's "hard" to find snakes in the tropics (some parts of the tropics anyway - we're really referring to rainforested regions rather than the tropics, and subtropical/temperate rainforests are probably even harder to find snakes in than tropical ones...probably because the numbers are genuinely lower). I don't think it has a lot to do with actual snake densities; no doubt densities vary for a huge number of reasons, but our perception of density (ie. what we're actually seeing) and actual density are probably two very different things (in all regions, not just the tropics).

edit: just saw the comment on the rat snake Hans - very cool.

I really wish I was able to do that kind of field herping when I was in Bangkok. There were about half-a-dozen species that I never saw because I never got a chance to get into the mangroves and mudflats. No clue where to go, no way to get there, and no idea what to do once I got there. If I had known then what I know now, I would have made a bigger effort to make at least one trip into them.

Thanks as always, Mr. Jackson! You're right, I should have titled the piece "Herping in the Rainforest etc.". The mangroves here, too, are quite nice for snakes, although we've so far only found three species in them (Banded Krait, Retic, Mangrove Cat Snake). There are trails into the mangroves, but I'm terrified of Estuarine Crocodiles, and since I know next o nothing about them, we usually stay away from those trails and roadcruise the swamps instead.


This is just one of the many reasons why people in this region hate Singapore

Hi everyone,

Sorry, I may not have been very clear, and actually did not discuss one thing.

Unfortunately, after living in Singapore for the majority of my life, the last few years have been disastrous for local nature reserve. The growth in visitors is incomprehendable, people enter with dogs, people swim in streams and let kids play in streams, and people enter with bikes.... I can't overemphasize what this has meant to my personal herping experience, or rather, the disintegration of it.

Thanks for sharing that....that must have been a major catastrophy, especially on such a small area.

It also throws a very different light on the myth of the efficient, squeaky-clean, law-obeying city state....

Since we're talking about herping tropical estuaries, does anyone here have a picture of Bitia hydroides?

Hi DavidG,

That definitely sounds sad - maybe I'm not so anxious to return to Singapore anymore. So much development has occurred there too (it's never-ending isn't it?), the very backyard from which I pulled 7 species of snake has been filled in and made a parking lot. Certainly a depressing situation

Wow. Thanks for the praise Hans! That's a mighty big compliment and I'm honored

This is a fun discussion, but there are so many facts at work here -- intraspecific competition, interspecific competition, niche availability, prey availability, thermal availability, evolutionary history and more that I'm glancing over -- I would guess it's nigh impossible to narrow this shortage down to just one.

While I would contend that forest mosaics (especially further north than Borneo) within the tropics have had a more complicated succession history than DavidG has given them credit for (think tropical savannahs, grasslands and gallery forests), I Think TNWJackson has hit the nail on the head here. Frankly we really don't have anything to base our density numbers on (to my knowledge). It's hard to claim that in primary forests snakes are at lower densities simply because we don't find them frequently -- there are a myriad of confounding variables that could be at work there. While we may have better ideas in the temperate regions, I doubt we'd even get a good idea of snake density if we had a line of people looking in every nook and cranny of 1 square mile of rainforest. In short, it's hard to say what's a rare species and what's just an uncommon species.

But to think that a man like Indraneil Das, who literally wrote the book on SE Asian and Indian reptiles, is still pondering this question makes me take more thought of the arthropod density issue.

But this makes me think --- is this really just true for snakes? There's a whole ton of Acanthosaura and Gonocephalus species out there that I've never come across; there's birds that live in "lowland forest" that people only see once in a blue moon. Is it just snakes or are all taxa in the tropics generally more specious but less frequently seen?

Ah, I would love to be around the water cooler discussing this at the World Congress of Herpetology this summer. I do believe this is one of the fundamental questions of tropical biology that has yet to be answered.

-Alex

Almost all of the snakes I found were during the afternoon after a rain or just after nightfall. But I haven't found many. I may give up flipping, as I have found only two snakes in this way in several years. If only I wasn't so addicted..

Sorry for the delayed response, but this helps a lot. In my area the forests are mostly disturbed secondary subtropical broad-leaf rainforest with endless leaf litter. Accessible areas are semi-wild with a smattering of bamboo and banana plantations along small valleys (often with streams coming down the mountain) that are harvested annually or bi-anually. Fallen trees are mostly taken for firewood, it seems. Besides the endless leaf litter it is karst terrain, so there are about a billion hiding places.. I think the only course of action will be to road cruise at night if I want to find them in any numbers.

You can print that out and hang it on the wall, baby.

But cobras and king cobras are diurnal and I enjoy vitamin D.. I would love to find me some of the local vipers, though.

What species have you got on your wishlist at the moment?

King Cobra, Sumatran Cobra, Tree Snakes (Twin-barred, Royal, and Paradise), King Cobra, Short Python, King Cobra, Blue Coral Snake, King Cobra, Ptyas carinata, and in case I don't sound enough like a broken record, King Cobra. (Hey, repeating his greatest wish ad nauseam finally worked for Cato the Elder - he of "Ceterum censeo, Carthaginem esse delendam" - even if it cost him his entire social life )

I finally read your blog.
After 2 trips to costa rica, I find your writings exactly right on the money.

so the answer to you question is a nice mixture of ecstasy and part nightmare..
but mostly the former.

enjoyed your blog. thanks , it makes me know I am right on track.

Hi Alex,

Sorry, I did not really mean to claim that there is no habitat diversity at all - you are right, there is some variety as portrayed by your examples. However, when discussing strictly the region Southern Penninsular Malaysia, Singapore, (Northern) Borneo (Sorry, I am not aware of far south Indonesian Borneo), such diversity is not limited. Have there been changes in the past? Quiet certainly, but now the overly dominant habitat type is lowland rainforest. Savannah woodland is not a natural habitat type in this region. I believe that the only really distinct other habitat types (other than mangroves) are peat-swamp forest and riverine forest. Do these have a very signficant impact on snake species? Not really. Yes, there are a few species (e.g. painted mock viper) generally restricted to this habitat, but many species of snake that occur in lowland rainforest also occur peat-swamp forest and riverine forest and the other way around. In spite of this, when looking at other things like amphibians, we do tend to see them occupying some more specific niches, and in turn they are often restricted to one forest type. So, yes, habitat types and species may be differentiated and so on, but, particularly for snakes, whether lowland/riverine/peat-swamp, it doesn't really matter too much - many species occur in each habitat, but correctly, are occasionally more abundant in one than the other. What does make a very signficant difference is whether that forest has been logged before or not, and, if it was, how long ago it was disturbed. I know this is all hypothetical, I have not done any actual research/data collection to justify my claims. They are just my beliefs, but can hopefully shed some kind of light on the issue.

Thanks, David

It can be very frustrating - I learnt the long, sticky, hard way that flipping is a waste of time. i've found the best way to get results is to trick someone who hates snakes into coming along on a night drive. For some reason snakes are attracted to these type of ppl and will not miss an opportunity to scare the shit out of the ophidiophobes. It's worked for me on at least 3 occasions when I've had an ophidiophobe with me - the snakes were almost throwing themselves out of the jungle. However, they've since wised up to this technique, either that or I need to change my ophidiophobe. Snakes are far smarter than we give them credit for, and tropical species can smell a herper coming a mile off!

= remarry?

I've never had any luck flipping here in Malaysia. With regards to the diurnal snakes, then I've usually come across them during mid-morning period, and in places where I wasn't looking or expecting to find them (schools, houses, gardens, road crossers etc). When I go out to where their natural habitat is, I very rarely see them (very early mornings being the exception). Cobras seem to be most active just after noon - the hottest part of the day - they are often crossing open ground, maybe looking for shade?. At night time definitely after light rain is the best time to find the nocturnal species on the little back roads.

LOL - she wasn't the ophidiophobe I was thinking of - she's a fairly willing victim. Although when she read your comment she did think it might be a good idea

Here is a fool-proof action plan for you to increase your chance of snake encounters. 1) identify a close family friend or colleague who is terrified of snakes ... it they find it difficult to even look at pics of snakes they are perfect (you will find these ppl on average usually spot a couple of snakes a week); 2) invite them out for makan-makan - you drive; 3) keep them chatting while you drive them home 'the scenic route'; 4) watch the snakes literally flashing at you from the side of the road!

You have to make sure this is someone you are quite close to, otherwise they will never speak to you again or will resist your efforts to comfort them and end up traumatised. Also - the more they trust you, the easier it is to trick them into coming out with you again.

1. Thanks for quoting me; I'm honoured (not that anyone noticed my quote lol)
2. I should have added "centum itinera et viam;" then my analysis would have been complete
3. F*%k Carthage ... let's get em

Fascinating topic. I have a few comments. First, one other factor that I think accounts for the difference in snake finds between tropical rain forest and the US or Europe is that in the latter areas there are defined seasons that regulate hibernation and mating. My experience in the latter regions is that the snakes appear from relatively concentrated hibernation sites, the vegetation is still depressed, and the snakes are about looking for mates. In tropical rain forests these conditions do not hold. Second, judging from the many posts on this forum (and partly from my own experience - though I made most of my finds road hunting) Costa Rica seems to be an exception from the rule. It would be interesting to get some people with experience from that country to join the discussion.
Finally, the tropics also includes savanna habitats and I have some experience herping in Kenya and Tanzania so I thought I would comment on that as it may be relevant. Many herpers and herpetologists have commented on the difficulty in finding snakes in these countries. One speculation has been that the large herbivores have something to do with this, which seems to be comfirmed in at least one recent study in Kenya. The population densities of the sand snake species Psammophis mossambica were found to be much lower in herbivore rich study areas than in areas with few large plant eaters. The link is the competition for plant food between large animals and the rodents that are the main prey of the snakes.

Nevertheless I have found it quite difficult and time consuming to find snakes also in herbivore scarce areas. I have also done some road hunting with scant results. However, I had the opportunity to try out another method during one year when I lived near the Kenyan coast. I started a network among the the local population in my area promising a small reward for each snake they could report to me so that I could find it in situ and take photographs. Once the people believed that this crazy mzungu would actually pay a shilling for this I got reports every day during the best months. In the 1970s a friend of mine who worked on various development projects in the highlands of southern Tanzania developed this method with very good results. His own attempts to find snakes were not very successful but once the locals and the project workers realized he was serious he was able to collect and observe several snakes most every day. My interpretation of the situation is that there are few reasons for snakes to be especially common in one restricted area at any one time , except in uniform grass/scrub habitat where water sources and rocks interrupts the ecological monotony.
There may also be a selection bias in comparing your finds in new areas with your finds in the US or Taiwan. In the US many people have particular localities which they know are good places to find snakes. Just as in the US if you travel to Kenya or Thailand and randomly look for snakes you can spend many days or weeks searching without finding much. I have lived in Kentucky for over 20 years and was a very enthusiastic field herper for the first years but gave up after a few years of finding garter snakes, black rat snakes, ring neck snakes and copperheads (I still enjoy finding these but would like to see some of the many other species that occur in the state). However, I know a couple of good spots on the Kenyan coast.

Tom Hakansson

Thank you very much for your fascinating input, Tom! I'll reply in detail a bit later!

That is a great article Hans!
Perhaps you will re-describe yourself as an explorer, instead of a herper, as I have.

I've heard of that technique working quite successfully. In more urbanized areas you could also try to get hooked up with the fire department or police or whoever is called to report venomous snakes to - when I saw the numbers for Bangkok, it was clear that public agencies get to report to hundreds of snake finds each year, and with mis-identification you would get to see not only a bunch of cobras, kraits, vipers, and pythons, but perfectly harmless stuff as well. They'd probably love to have someone with them who knows how to handle stuff.




I very strongly agree with that. In a lot of the habitat I looked at, it was "fine" for snakes everywhere...which makes finding the particular spot they'll be at any one time more difficult. When temps, humidity, and cover don't need to be particularly controlled for...