Some pictures from the Cres-Lošinj archipelago

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Re: Some pictures from the Cres-Lošinj archipelago

Postby Ilian Velikov » Sun May 21, 2017 1:40 pm

Mario Schweiger wrote:Ilian Velikov wrote:

- In the long term are snakes in places with high road mortality capable of learning to avoid roads?

my opinion: for sure not. how it would work? other snakes (or any herps) will watch another specimen being over rolled and think. " I never will go onto a road, its really dangerous.


Mario, I meant in a really long term. People have been building roads for some time now and they'll continue building them. Yes, I know - more cars now then ever and all that but I'm sure horse carts used to run over snakes too. Snakes will continue to co-exist with people in that environment (I don't believe road traffic would be the cause of world snake extinction any time soon). How did snakes learn to avoid people and other major predators and don't care much if cows for example are near by? Did snakes watch people kill other snakes? I don't know...Not sure what the mechanism is but it's a fact that animals sometimes can adopt to a new/changing environment faster than we think. My question was if snakes have the mental capacity to learn to avoid if not roads at least approaching cars.
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Re: Some pictures from the Cres-Lošinj archipelago

Postby Michal Szkudlarek » Sun May 21, 2017 1:49 pm

Ilian Velikov wrote:
Mario Schweiger wrote:Ilian Velikov wrote:

- In the long term are snakes in places with high road mortality capable of learning to avoid roads?

my opinion: for sure not. how it would work? other snakes (or any herps) will watch another specimen being over rolled and think. " I never will go onto a road, its really dangerous.


Mario, I meant in a really long term. People have been building roads for some time now and they'll continue building them. Yes, I know - more cars now then ever and all that but I'm sure horse carts used to run over snakes too. Snakes will continue to co-exist with people in that environment (I don't believe road traffic would be the cause of world snake extinction any time soon). How did snakes learn to avoid people and other major predators and don't care much if cows for example are near by? Did snakes watch people kill other snakes? I don't know...Not sure what the mechanism is but it's a fact that animals sometimes can adopt to a new/changing environment faster than we think. My question was if snakes have the mental capacity to learn to avoid if not roads at least approaching cars.

snakes naturally run away from anything big approaching, especially if it makes noise, not necessarily cars, i tihnk
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Re: Some pictures from the Cres-Lošinj archipelago

Postby Ruggero Morimando » Sun May 21, 2017 1:55 pm

Michal Szkudlarek wrote:
Ilian Velikov wrote:
Mario Schweiger wrote:Ilian Velikov wrote:

- In the long term are snakes in places with high road mortality capable of learning to avoid roads?

my opinion: for sure not. how it would work? other snakes (or any herps) will watch another specimen being over rolled and think. " I never will go onto a road, its really dangerous.


Mario, I meant in a really long term. People have been building roads for some time now and they'll continue building them. Yes, I know - more cars now then ever and all that but I'm sure horse carts used to run over snakes too. Snakes will continue to co-exist with people in that environment (I don't believe road traffic would be the cause of world snake extinction any time soon). How did snakes learn to avoid people and other major predators and don't care much if cows for example are near by? Did snakes watch people kill other snakes? I don't know...Not sure what the mechanism is but it's a fact that animals sometimes can adopt to a new/changing environment faster than we think. My question was if snakes have the mental capacity to learn to avoid if not roads at least approaching cars.

snakes naturally run away from anything big approaching, especially if it makes noise, not necessarily cars, i tihnk


Sorry Michal, but you think wrong, probably by lack of direct experience.
Many snakes rest quiet when something big approaches them. In Europe especially Zamenis longissimus and Zamenis situla. And this happens on the roads as well as "in the woods". But also a big Malpolon stays often motionless on a trafficked road, watching the cars which move around it with its elevated head... ;) And unfortunately it rests very often in this position for enough time to be killed.
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Re: Some pictures from the Cres-Lošinj archipelago

Postby Michal Szkudlarek » Sun May 21, 2017 1:58 pm

Ruggero Morimando wrote:Sorry Michal, but you think wrong, probably by lack of direct experience.
Many snakes rest quiet when something approach them. In Europe especially Zamenis longissima and Zamenis situla. And this happens on the roads as well as "in the woods". But also a big Malpolon stays often motionless on a trafficked road, watching the cars which move around it with its elevated head... ;) And unfortunately it rests very often in this position for enough time to be killed.

you are right, im not snake expert :oops:
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Re: Some pictures from the Cres-Lošinj archipelago

Postby Ilian Velikov » Sun May 21, 2017 2:12 pm

Ruggero Morimando wrote:I could make you a list of the causes that in 40 years caused the decline and/or the total destruction of snakes around my house, where I live since 1972, but I can reassure you that at number 1 I will put roadkills.


I'd say you have to switch the places of some causes in your chart. From what you described I'd say those growing in numbers wild boars have a much much bigger impact on your local snake population than road traffic and you'd have to come up with some really solid proof to convince me otherwise. Wild boars would maybe indeed eat a snake and most definitely snake eggs, but above all they destroy snake habitat on a large scale. And there's your number 1 reason for snake decline. If the snakes don't have a network of good places to rest, hunt, hibernate, breed and all of this in close proximity you can be sure there will be no snakes in this area. They would rather die out or move to more suitable places, which by the way could be the case in your area. Why do you think the reason you see less snakes is because all of them died? On the other hand a few snakes killed on the road wouldn't have such an impact on the overall population. Is your area changed so much since you live there? Except for the bigger number of cars are there many new roads built?

Ruggero Morimando wrote:And, please... you cannot compare "road kills" with a sort of "natural predation"...

I meant as in the frequency and number of dead snakes. I can assure you that if you have a lake with a road next to it annually much bigger number of snakes die in the lake or surrounding area from natural predation than on the road next to it.

Ruggero Morimando wrote:And a natural predation as the one by Circaetus gallicus has certainly more selectivity than roadkills, in which every snake that crosses a road or bask over it is killed without distinctions

That's simply not true! Not every snake that crosses the road is inevitably killed. A lot of them cross roads many times and get to survive. As I said it's down to chance.

I'm not saying road traffic can't be an issue especially on small islands, but I think there's many other threats to snake survival on which we should concentrate first if we want to preserve them. And anyway you stated your opinion on what the problem is but I also asked what the solution could be. What do you think? I don't think many of us would be willing to switch back to riding horses or go on field trips in nature by long distance running on foot...? And having said that how many of us even hardcore herp lovers would drive along a road in a considerable speed with other cars behind you for example and break suddenly risking car crash and killing themselves, maybe their family and the passengers in the car behind them to save a baby snake on the road?
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Re: Some pictures from the Cres-Lošinj archipelago

Postby Michal Szkudlarek » Sun May 21, 2017 2:18 pm

"Not every snake that crosses the road is inevitably killed. A lot of them cross roads many times and get to survive. "
it is otherwise regarding toads, toads cannot jump high so if they manage to cross a road they have problem with curbs
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Re: Some pictures from the Cres-Lošinj archipelago

Postby Ruggero Morimando » Sun May 21, 2017 2:31 pm

Ilian Velikov wrote:
Ruggero Morimando wrote:I could make you a list of the causes that in 40 years caused the decline and/or the total destruction of snakes around my house, where I live since 1972, but I can reassure you that at number 1 I will put roadkills.


I'd say you have to switch the places of some causes in your chart. From what you described I'd say those growing in numbers wild boars have a much much bigger impact on your local snake population than road traffic and you'd have to come up with some really solid proof to convince me otherwise. Wild boars would maybe indeed eat a snake and most definitely snake eggs, but above all they destroy snake habitat on a large scale. And there's your number 1 reason for snake decline. If the snakes don't have a network of good places to rest, hunt, hibernate, breed and all of this in close proximity you can be sure there will be no snakes in this area. They would rather die out or move to more suitable places, which by the way could be the case in your area. Why do you think the reason you see less snakes is because all of them died? On the other hand a few snakes killed on the road wouldn't have such an impact on the overall population. Is your area changed so much since you live there? Except for the bigger number of cars are there many new roads built?

Ruggero Morimando wrote:And, please... you cannot compare "road kills" with a sort of "natural predation"...

I meant as in the frequency and number of dead snakes. I can assure you that if you have a lake with a road next to it annually much bigger number of snakes die in the lake or surrounding area from natural predation than on the road next to it.

Ruggero Morimando wrote:And a natural predation as the one by Circaetus gallicus has certainly more selectivity than roadkills, in which every snake that crosses a road or bask over it is killed without distinctions

That's simply not true! Not every snake that crosses the road is inevitably killed. A lot of them cross roads many times and get to survive. As I said it's down to chance.

I'm not saying road traffic can't be an issue especially on small islands, but I think there's many other threats to snake survival on which we should concentrate first if we want to preserve them. And anyway you stated your opinion on what the problem is but I also asked what the solution could be. What do you think? I don't think many of us would be willing to switch back to riding horses or go on field trips in nature by long distance running on foot...? And having said that how many of us even hardcore herp lovers would drive along a road in a considerable speed with other cars behind you for example and break suddenly risking car crash and killing themselves, maybe their family and the passengers in the car behind them to save a baby snake on the road?


You write: That's simply not true! Not every snake that crosses the road is inevitably killed. A lot of them cross roads many times and get to survive. As I said it's down to chance.

But you must read my assertions with some elasticity...
It's "not true" only if while the snake is on that road, on that road passes no car. Or passes a car and TOTALLY casually that car does not hit the snake, without any relationship to a possible "selection".
And as I've written a natural selection mechanism will need thousands of years to take place. Or would you think that with road traffic snakes will have enough time to be selected in a darwinian way by their speed or intelligence to avoid roads?

Your lake example could be right if the lake is big and wild, with only small and few roads around it, or many roads but with few traffic.
Could be wrong with a small lake, with few natural predators and many trafficked roads around it.

As regards my region, Oltrepo' Pavese, yes, I can write and say loud that the MAIN difference from 1970 to 2017 is an increased traffic on roads (I could say e.g. with absolutely no scientific meaning/claim, of a factor from 1 to 1000!) AND the increased presence of wild boards. And, surely, the opening of new roads with the tranformation of rural roads with no traffic to asphalted roads with heavy vehicular traffic.
Other factors are less important in my opinion and experience (which is not poor) and I could speak about them. But then we go totally off topic... :?
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Re: Some pictures from the Cres-Lošinj archipelago

Postby Ilian Velikov » Sun May 21, 2017 2:33 pm

Michal Szkudlarek wrote:it is otherwise regarding toads, toads cannot jump high so if they manage to cross a road they have problem with curbs

True, but not all roads have curbs, not all toads cross roads and from those that do not all die. In fact plenty of them survive, and the fact that the common toad is one of the widest spread European amphibians and still quite "common" is a proof that road traffic is not such a problem for them in the bigger picture.
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Re: Some pictures from the Cres-Lošinj archipelago

Postby Ruggero Morimando » Sun May 21, 2017 2:38 pm

Ilian Velikov wrote:
Michal Szkudlarek wrote:it is otherwise regarding toads, toads cannot jump high so if they manage to cross a road they have problem with curbs

True, but not all roads have curbs, not all toads cross roads and from those that do not all die. In fact plenty of them survive, and the fact that the common toad is one of the widest spread European amphibians and still quite "common" is a proof that road traffic is not such a problem for them in the bigger picture.



So, why are present in more culturally evoluted Countries people who make tunnels under roads for toads passage? Just in order to waste public or private money? :? ;)
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Re: Some pictures from the Cres-Lošinj archipelago

Postby Ilian Velikov » Sun May 21, 2017 2:44 pm

Ruggero Morimando wrote:And as I've written a natural selection mechanism will need thousands of years to take place. Or would you think that with road traffic snakes will have enough time to be selected in a darwinian way by their speed or intelligence to avoid roads?


It seems you misunderstood what I said, so I'm going to clarify it again. I only made the comparison between roadkill and natural predation in terms of the frequency and number of snakes killed, and the fact that both depend to a big extend on chance. Unlike the destruction of a habitat which inevitably kills anything that lived in it roadkill does have some flexibility and yes, selection - not all snakes die on the road, and a road (even with heavy traffic) going through a snake habitat doesn't inevitably mean demise for the local snake population. So in this regard you can look at it as one of those things that do kill snakes but not necessarily exterminate them, hence my comparison with natural predation.

And again, what's the solution?
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