The following post is to answer some great questions a man at Facebook sent me about some things he has observed about snakes crossing the roads around Buriram, Thailand. I have also given this subject a bit of thought and I have some ideas I’ll list below his post here.
Hi Vern, maybe you are able to give some info on this?
In the area of Phra Khon Chai / Phaisan Province of Buriram two time in a period of two weeks (that might not matter) there have been snakes passing the road, when i was on a motorbike. In Phaisan, village road, daytime, had to break not to hit the animal. Small, around 40 cm long, brownish-green with pattern. Between Ban Gaem and Phra Khon Chai, Main 24 Highway very busy, almost hit the snake, which turned away quickly and made it, but moved on the next moment. Shiny plain black, small, 50 cm at the most. I am far from being an expert on snakes or knowing much about animal behaviour, but as far my information goes, snakes are highly sensitive for smell, sound and vibrations, yet not seeing well.
The vibrations of course because they move on the ground.
The question is, why do they even come close to roads? The poison exhaust, the loud roaring sounds and the vibrations of the vehicles, that should be similar to an earthquake disaster for a snake, should keep them very much away from it.
Is it, they do get used to it and try to handle crossings ?
Am I wrong and their senses aren´t affected as much, as i think?
Are the snakes attracted by something (food etc) on the other side, which makes them take the courage to face the danger? Or do they loose their way due to confused senses, when they come to close to that threats (heavy exhaust, awful sound and ground vibration) and therefore act in panic more then anything they could do on purpose or instinct ?
All great questions Bernhard! I have often thought about this same thing as I see a snake shoot across the road without a chance in the world of making it across without being run over by a vehicle. I’ve run over one snake myself that darted out right in front of my motorbike before I could react. It was the Ahaetulla prasina – beautiful snake!
So why do snakes cross the road?
I do think they become accustomed to the vibrations of cars passing if they live close to a road. If they don’t live near one, and then suddenly find themselves near one, I don’t think they understand what the vibrations might mean, so they just go across like they are crossing some rock. I think snakes’ sense of vibration isn’t as strong as people think it is. I have MANY times walked right up to a snake on the ground before it felt me. But once they see me, they go quickly.
Conceivably a snake could feel cars on the road as they’re coming toward it. If anywhere but on the very side of the road, the snake wouldn’t have enough time to get out of the way in most cases. The road is much too slippery for them to grip well and if they twist faster, they don’t go anywhere, as they just slip around in one spot.
Snakes have great eyesight – unless in shed. The king cobra is said to be able to see someone 100 meters away.
The snakes can surely smell the exhaust of vehicles, but they don’t know what it means. I have found snakes in swimming pools with a strong chlorine smell. I’ve found snakes inside my motorbike which smells of oil, plastic, and gasoline. Again, I think they just smell these things often and they probably are not affected that much by them. Their drive to eat and cool off is stronger than the need to avoid harsh smells.
Keep in mind, all of this is is guessing on my part. I think that’s all we can do is guess.
Snakes are very mobile. Some of them. The green snake you saw might be the Chrysopelea ornata, the Golden Tree Snake. They are quite active during the day and I’ve seen many crossing the roads.
The dark snake is anyone’s guess, but maybe the monocled cobra.
King cobras move around a 10-20 km area of space typically. I think that was the range. Someone correct me if you have a good source. Much of the time an active king is tracking the scent of a snake it smells. If a tasty rat snake crossed the road in a spot, the king may also cross it.
I don’t know that snakes ever really lose their way. I think they don’t care where they’re going or end up, as long as the habitat is suitable and food is close by. I think once they find a nice little home that is safe, has food, and is the right humidity and temperature, they’ll stay in that area and not feel any need to go exploring. Unless looking for a mate. The sex drive in snakes is strong and if a male smells a female in estrous across the road, it will cross the road without a thought.
Anyway, those are just my guesses. Anyone can feel free to chime in on this discussion!