How do snakes act in the subtropics? (2 year old post)

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Ruxs
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How do snakes act in the subtropics? (2 year old post)

Post by Ruxs »

This question has been jeopardising my hunt for the Snakes of South-Thailand for quite a bit of time. Here in the deep south peninsular the rainy season is long and boring and in some areas of Forest, e.g Khao Sok national park/Surat Thani, the Snake activity stops completely in times of rain. But in places like Yala province when the rainy season lasts about 7 months of the year, are the snakes affected?
In the hot parts of the USA the rain brings out the snakes, but here it seems to do the opposite - is it pointless to Roadcruise after rain? This is my plea to the educated minds of FHF to please answer this question as best as possible.

Note: It isn't quite aseasonal here as there is a noticeable dry season.

Anyway, here is a teaser for a post I hope to make once we get wifi in my home :) Quality seems a bit downed though...
Image
Cylindrophis ruffus (Red-Tailed Pipe Snake)
Thanks in advance.
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Hans Breuer (twoton)
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Re: How do snakes act in the subtropics?

Post by Hans Breuer (twoton) »

I can only speak for Borneo, where the seasons are quite different from Thailand, but rainy season or not, I road cruise every chance I get - I almost always find something. If you can, do it....even DURING the rain which is the time to find the coolest frogs!
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Keeper
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Re: How do snakes act in the subtropics?

Post by Keeper »

I don't know about Thailand, but at the rainforest at southern Tibet and southern Yunnan, snakes do got affect by rain, and they are not really active during the rain season. Did you try forage at night? Try the night right after the rain.
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Re: How do snakes act in the subtropics?

Post by DavidG »

Sorta like Hans, I can only speak for Singapore... I do not have a driving license, so cannot really confirm anything about roadcruising! What I do know is that certain roads are occasionally pretty 'good' for roadkill. This goes to show that snakes of course do cross the roads here, possibly even staying on the during the night? Hopefully I can add some ideas about snakes crossing the road here in the tropics.

Tropics and snake migration across roads:

The thing about the hot tropics - roads tend to be crossing points for herps, but no so much places to stay warm during the night! In fact, most snakes here shelter from the midday heat, and are active at night. This may suggest that the night temperatures are suitable for the activity many of the local snake species. Of course, it may be related to other things as well. E.g. frogs/lizards/geckos often stay exposed at night - frogs breed and eat, so do geckos, lizards/agamids sleep on foliage. This means that food is readily available to nocturnal snakes. Effectively, a road is not so much a place for the snake to stay warm - I believe that the temperatures are fine for the snakes!

What is also important is that not only a roads easily warmed by the sun, the black tarmac may occasionally be too hot too handle. Yes, you can find fried reed snakes. Many of the smaller snake species such as calamaria and blind snakes, are unable to loose heat at a sufficient rate from their small bodies (relative to the rate at which heat is transferred to their bodies) - they overheat, and literally bake. The hot road may be a barrier for many species to cross during the day. Snakes will cross the road at night. One may argue that rain helps to cool down the road sufficiently as well, which thus removes the barrier to a snake's cross-road migration. Furthermore, the smaller species of snakes (for which a hot road could act as a sufficient barrier to migration during the day) are also terrestrial or burrowing species. Rain tends to drive many of these species from out under ground to the surface (otherwise they drown). Hypothetically speaking, the combination cooling roads and saturated soils, could potentially help these small snakes move across the road (although this idea is of course a little far-fetched :D ).

Rain is an important factor in the tropics. It stimulates immensely, the breeding activity of many frogs in temporary puddles (e.g. on the forest floor or in tree holes). In addition, it brings out megatons of flying ants and termites, which may trigger increased feeding activity by other species, thus 'activating' many snakes. Why rain in some places results in increased or decreased snake activity - I don't believe that there is one absolute trend! I guess it is related not only to whether rain stimulates activity of a snake's diet, but also, it probably depends on the snake species. Maybe in some subtropical places on earth, snakes have 'evolved' to take shelter from rain (and live during warm periods), and in other subtropical areas the other way around?
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Re: How do snakes act in the subtropics?

Post by Hans Breuer (twoton) »

David,

I really love your elaborate answers - I always learn a lot!

Maybe I'll soon get closer to the answer why the snake crossed the road around these parts, as I'm embarking on the first scientific survey of my life: Neil Das has encouraged me to use my roadcruising to collect even more data than I usually do, and and to write a paper about my findings after a year of collecting. To facilitate this, he's provided me with oodles of papers about roadcruising, but almost all of those concentrate on North America's temperate zones and therefore contain the (there) very important factor of basking, something snakes don't need down here, as you rightly said. I'll be collecting data on literally everything I see - the number of hunters, unusual numbers of termites, ants, bats etc., slash & burn cycles, fruiting seasons, moon phases, down to the intoxication degree of passing drunken drivers (that should be easy, they're usually sauced up to the gills).

PS: I've found fried reed snakes here before, too.

PPS: No driving license...too young or personal choice (you don't really need a car in Singapore, even if you could afford one :-))? Your knowledge of natural history makes me believe you can't be that young (of course, there's always the odd wunderkind)
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Ruxs
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Re: How do snakes act in the subtropics?

Post by Ruxs »

Keeper wrote:I don't know about Thailand, but at the rainforest at southern Tibet and southern Yunnan, snakes do got affect by rain, and they are not really active during the rain season. Did you try forage at night? Try the night right after the rain.
Thanks. I always thought the rain brought out snakes, but I never find them after rain, it's always when we have had a dry patch.
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Re: How do snakes act in the subtropics?

Post by krisbell »

Hi Rupert,

I really have no idea how to answer your question but a few considerations:

I'm sure I saw a simulation someone had made on this site regarding virtual cruising where you could put in your hypothetical speed, how many snakes would cross a road and how fast you wanted to cruise at and the results are extremely interesting in terms of how much stochasticity there is in the subsequent results. If you replay the simulation over and over again with a set number of snakes crossing the road, you will find that results vary widely from no snakes found to almost every snake found (and everything in between). I can keep clicking on this simulation over and over again so that I have effectively done 50 nights road cruising in a few minutes. Now I know you are an experienced herper but this variation is massive and would be very difficult to pick up in the field where there are also so many other variables such as moon phase, season, temps, elevated road traffic (weekend?), recent passing of a predator etc etc and all this is assuming you herp the exact same patch in the exact same way for the exact same length of time. What I am basically saying is that without systematic data of the type that perhaps Hans is collecting now it is very difficult to get an accurate idea of just how much rain does detract from road cruising. It is perfectly possible you get a poor roll of the dice herp wise on a number of nights where it happens to be raining (for whatever reason - unlucky, wrong habitat, tired eyes etc) and from then on you have the idea that road cruising in the rain is no good. So future cruises you tend to go out in the dry and attribute a good night to the dry conditions and anytime you find yourself in the rain and find a snake you attribute it to a lucky and unusual find when in actual fact there is no significant difference in success. I'm not suggesting there is no truth in what you are saying and I would certainly think heavy rain would alter the species you see but I would just urge caution given how random road cruising results can be even in perfect habitat with a good pair of eyes. I road cruised a stretch of road in Australia the same time as another bunch of guys and I found 5 brown tree snakes, a black headed python and a curl snake, and they found a mulga. Same road, same technique, same time but totally different results.

A different point regarding road cruising in rain is that I dont believe roads are much of an attraction for most snakes. They are flat, hard, unnatural, noisy, smelly and open and as such I believe most snakes avoid them where possible. I have mentioned it in previous posts but I can count on the fingers of one hand how many snakes I have encountered on a road that were orientated along the road rather than across it, or how many snakes looked like they were resting or hunting or otherwise 'using' the road (very subjective I know but I still feel you get a 'feel' for these things). So assuming that snakes do dislike crossing roads you need to provide a reason for them to do so. In the case of rain we know this brings out amphibians that are a primary source of food for many snakes. If I was a viper and desperately wanted to eat and one night it rained sufficiently that a small stream or puddle formed within my reach and a few frogs turned up then I would have very little reason to want to move. If on the other hand it had been super dry and I was getting hungry, I would have no choice but to move in search of a better spot - hence increasing the likelihood of being roadcruised in the dry. This system can work in the opposite way in flat places where persistant heavy rainfall floods places where snakes are inhabiting and forces them onto small patches of higher ground which often turn out to be roads. This has worked well for me in Florida and Australia where heavy rains have basically flooded surrounding areas and turned the roads into a living mass of snakes. Different places, different conditions, different results.

After all the above - I personally prefer to road cruise in the dry, though I know experienced herpers from SE Asia that prefer it to be wet.
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Re: How do snakes act in the subtropics?

Post by dery »

In the debated subtropics in the Southeastern US, roadcruising is both a goldmine and a no-no depending on the locale. For example, in northern AL, no-no/in the St. Andy's Bay Region it is a goldmine. In South Florida's Neotropics, no-no. Sorry I can't help with foreign subtropic regions much. Though I'm guessing locale matters there too.
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Re: How do snakes act in the subtropics?

Post by jonathan »

krisbell wrote:I'm sure I saw a simulation someone had made on this site regarding virtual cruising where you could put in your hypothetical speed, how many snakes would cross a road and how fast you wanted to cruise at and the results are extremely interesting in terms of how much stochasticity there is in the subsequent results. If you replay the simulation over and over again with a set number of snakes crossing the road, you will find that results vary widely from no snakes found to almost every snake found (and everything in between). I can keep clicking on this simulation over and over again so that I have effectively done 50 nights road cruising in a few minutes. Now I know you are an experienced herper but this variation is massive and would be very difficult to pick up in the field where there are also so many other variables such as moon phase, season, temps, elevated road traffic (weekend?), recent passing of a predator etc etc and all this is assuming you herp the exact same patch in the exact same way for the exact same length of time. What I am basically saying is that without systematic data of the type that perhaps Hans is collecting now it is very difficult to get an accurate idea of just how much rain does detract from road cruising. It is perfectly possible you get a poor roll of the dice herp wise on a number of nights where it happens to be raining (for whatever reason - unlucky, wrong habitat, tired eyes etc) and from then on you have the idea that road cruising in the rain is no good. So future cruises you tend to go out in the dry and attribute a good night to the dry conditions and anytime you find yourself in the rain and find a snake you attribute it to a lucky and unusual find when in actual fact there is no significant difference in success. I'm not suggesting there is no truth in what you are saying and I would certainly think heavy rain would alter the species you see but I would just urge caution given how random road cruising results can be even in perfect habitat with a good pair of eyes. I road cruised a stretch of road in Australia the same time as another bunch of guys and I found 5 brown tree snakes, a black headed python and a curl snake, and they found a mulga. Same road, same technique, same time but totally different results.
This is just fantastic advice, and goes for a lot of the "conclusions" we make about life in general. Human beings love to find patterns...and will claim patterns based on the flimsiest evidence. Sometimes your pattern turns out to be right...but without systematic observation over a long period of time, it can be hard to be sure.


krisbell wrote:A different point regarding road cruising in rain is that I dont believe roads are much of an attraction for most snakes. They are flat, hard, unnatural, noisy, smelly and open and as such I believe most snakes avoid them where possible...
For what it's worth, sidewinders in SoCal seem to use roads to thermoregulate. I would find them in various non-moving positions with their bodies spread out as wide as possible, pressed up against the road's surface. Sometimes I would even find the same 'winder in the same spot an hour later. I've heard other reports of them using train tracks the same way, so they appear to use unnatural surfaces in at least some instances.
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Re: How do snakes act in the subtropics?

Post by Kelly Mc »

Flat, hard, and grainy may not be as unnatural as it sounds.

A temperature impetus could surpass the smell of industrial residue in the open air and after many habituated generations.

Road temperature such a magnetic physical pull it has even surpassed generations of being squashed, so far. But evolution continues.
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Re: How do snakes act in the subtropics?

Post by withalligators »

I was in Khao Sok for about 2 weeks in March, and I saw more snakes there, especially when it was raining, than anywhere else in Tland. Do the hike to the bridge at night and then poke around the river.

Cheers,
Alex
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Re: How do snakes act in the subtropics?

Post by jonathan »

A study by the Bangladesh Python Project in Lawachara National Park found DOR peaks in April (early hot season), July/August (middle of rainy season), and October (just after rainy season). The July/August peak was arguably the most productive, and certainly the longest.

http://www.academia.edu/2501753/Monsoon ... Bangladesh



We were there in early rainy season, and generally didn't find much on the roads. One or two snakes were found on the roads during rain, and a couple were found on the roads not during the rain.
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Re: How do snakes act in the subtropics? (2 year old post)

Post by Ruxs »

For anyone who hasn't noticed, I made this post 2 years ago before I started fanatically herping South-East Asia so my knowledge on the matter has improved quite significantly since then. However, it's still an interesting topic and people are bringing up good points on the matter.

From a year of herping in thailand, I found that nightly herp activity really peaked around the start of the rainy season in May/June, but started to peter out ever so slightly from July onwards. In June, I would rarely drive for long in the evening without finding something, whereas before there were often nights when the roads were bare. However, my knowledge was growing throughout the year so the influx of finds towards the latter parts of my time could just be down to experience. That said, I do know for sure that I have never really had any luck road cruising when it was actually raining - dry nights after daytime rain though, always a good thing. I used to be far more superstitious about this kinda thing, but after countless trips at different times of the year I can tell you that nothing is certain and if you put the effort in you can almost, almost always find something. Bear in mind that I speak specifically of the southern thai peninsular and malaysia/tropical indonesia, if you head to Hua Hin at the very north of the peninsular, everything is completely different.
withalligators wrote:I was in Khao Sok for about 2 weeks in March, and I saw more snakes there, especially when it was raining, than anywhere else in Tland. Do the hike to the bridge at night and then poke around the river.

Cheers,
Alex
Yes, contrary to driving, walking in the forest while it's wet can be quite rewarding, although its more comfortable when its dry and I assure you there are better places to herp in that area than Khao Sok.
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Re: How do snakes act in the subtropics?

Post by krisbell »

Kelly Mc wrote: Road temperature such a magnetic physical pull it has even surpassed generations of being squashed, so far. But evolution continues.
I dont think you can directly attribute seeing snakes dead on the road as a magnetic physical pull, as per my point above regarding most snakes simply crossing roads to access resources. Equally you cannot assume that evolution would have any measurable impact on the number of DORs - to take it at extremes you will have to wait a while for snakes to evolve to fly over roads. Even at its most simple form in terms of road avoidance behaviour, you have to offset this with increased numbers of roads and increased numbers of cars resulting in more DORs even if snakes have genetically evolved to somehow avoid them, or stop/look/listen before crossing.
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Re: How do snakes act in the subtropics?

Post by Kelly Mc »

krisbell wrote:
Kelly Mc wrote: Road temperature such a magnetic physical pull it has even surpassed generations of being squashed, so far. But evolution continues.
I dont think you can directly attribute seeing snakes dead on the road as a magnetic physical pull, as per my point above regarding most snakes simply crossing roads to access resources. Equally you cannot assume that evolution would have any measurable impact on the number of DORs - to take it at extremes you will have to wait a while for snakes to evolve to fly over roads. Even at its most simple form in terms of road avoidance behaviour, you have to offset this with increased numbers of roads and increased numbers of cars resulting in more DORs even if snakes have genetically evolved to somehow avoid them, or stop/look/listen before crossing.
Amusing hyperbole to a comment made about poikilotherms thermoregulating.


No I dont assume - oh sorry it was - "directly attribute" any of what you said. All which would be ridiculous.

What I would muse curiously is that adaptations (sensate) that occur because of survival deficit would be a product of evolution like all the rest.

Equally, I surmise that rather than looking both ways before crossing - the snakes would actually learn to form a :thumb: with their bodies on the side of the road, and integrate their quest for resources with our own vehicular traveling patterns.
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Re: How do snakes act in the subtropics?

Post by krisbell »

Kelly Mc wrote:
krisbell wrote:
Kelly Mc wrote: Amusing hyperbole to a comment made about poikilotherms thermoregulating.
Sorry my bad - I misread as a super serious thought!
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Re: How do snakes act in the subtropics? (2 year old post)

Post by Kelly Mc »

Im sorry too I didnt mean to seem snarky.

No Krisbell - I go on and on and on (and on)with serious superthoughts :lol:

SST's... gotta remember that! :)
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Re: How do snakes act in the subtropics?

Post by Kelly Mc »

krisbell wrote:
Kelly Mc wrote: Road temperature such a magnetic physical pull it has even surpassed generations of being squashed, so far. But evolution continues.
I dont think you can directly attribute seeing snakes dead on the road as a magnetic physical pull, as per my point above regarding most snakes simply crossing roads to access resources. Equally you cannot assume that evolution would have any measurable impact on the number of DORs - to take it at extremes you will have to wait a while for snakes to evolve to fly over roads. Even at its most simple form in terms of road avoidance behaviour, you have to offset this with increased numbers of roads and increased numbers of cars resulting in more DORs even if snakes have genetically evolved to somehow avoid them, or stop/look/listen before crossing.
Krisbell I would like to apologize twice, since reading this again it was clear i was being defensive as the evolutionary implication in my post was a weak one - precisely because of the reasons you broke down in your post.

As I think of it I am sad. I think of jungles and deserts and delicate journeys thwarted suddenly in a huge suddenness of our dominion over each terra face.

What you said was absolutely true, and on second thought understand your epitome of charactarizations.

It has made me sad to think of. Cuz Yeah you're right. The impacts we have are so rapid and chaotic, my understanding of evolution is limited, but i know it continues and it makes me wonder if in effect we are even wounding time.

On a more playful note how about those geckos - such fantastic morphology of lichen, moss, bark and vine look alikes. Perhaps more likely in a silly theoretical future the guys skittling flatly around human habitation will phenotype door hinges, patchy plaster and picture frames. :lol:

This wasnt SST - but i wanted to connect with you about what you said.
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