Why aren't all snakes venomous?

[Craig krup]

And don't say, "because they aren't". That's like replying to the question, "Why did you nail your **** to a tree?", by saying, "Because I wanted to".

You'd think being venomous would be an advantage - you can kill prey more easily, and you can defend yourself. Basic evolutionary theory tells you that if something is a straightforward win then the gene for it should spread like wildfire in the gene pool. Being able to digest lactose was a straightforward win in Northern Europe, so people who had the gene for it had more kids, were bigger and healthier and so northern Europeans are almost all lactose tolerant. Venom is produced by a modified salivary gland. The biological costs are pretty low. You'd think, therefore, all snakes would be venomous, unless there's a powerful selective pressure in the opposite direction.

Here's my suggestion. Snakes are distinctive in their coloration. Snakes have lived in close proximity to humans for thousands of years. So being venomous is dangerous because humans who worry about themselves and (especially) their kids will kill you. So the reason that cobras stand up, the reason rattlesnakes rattle and the reason many snakes will give a massive hiss if you get close, is so that you can go your way and they can go theirs. So when people say that some non-venomous snakes have the same coloration as the venomous in order to get the benefit without the cost that's 180 degrees wrong. It's the venomous snake that's trying to look non-venomous, so that you - the farmer 2,000BC - leave this useful rat eater alone, rather than giving it a thorough whacking with a whippy stick. Snakes - they probably won't start it, but they may well finish it.

A.Z. Oologist

[i wish ]

[puukao]

why aren't all snakes non-venomous?

why aren't all animals venomous?

why can't all animals fly?

......on the origin of species...... good read

[Murgatroyd]

One might as well ask why all snakes aren't constrictors... it's an equally effective method of dispatching prey... Or why some lay eggs and some give birth to live young... They took a different route through the fractals of evolution.

[kannot]

Why didnt snakes grow bigger brains and make guns, depends on their prey, if you want to get REALLY stupid you could say "god" ( refuse to use capital letter) made them that way.

Edited November 24, 2015 by kannot

[Crossy]

Not specifically Thailand related, moving it to Pets Health The Pub.

[vogie]

Is it me that's really stupid or is the poster really clever?

[chrisinth]

"Snakes have lived in close proximity to humans for thousands of years"

I think that is one flaw in your argument, the wrong way round........................

[CaptHaddock]

Producing venom is not getting something for nothing. The biological cost is sufficient that some venomous species make efforts to conserve venom. For instance, it is more dangerous to be bitten by an immature fer de lance than an adult because the adults conserve venom by injecting less of it. Some previously venomous species of snakes have lost the ability to produce venom as their prey species have changed. The very fact that venoms are not universal implies that there is indeed a biological cost involved. In biology everything has a cost. It's just harder to observe such costs.

Lactose tolerance also incurs costs. For example, lactose tolerance is associated with higher incidence of celiac disease. Lactose tolerance developed with the agricultural revolution as the reduction of meat in the diet meant that farmers had to get vitamin D from a new source, milk.

[CharlieH]

They might not all be venemous, but should all be treated as such for safety sake.

Unless you actually know the difference.

[kannot]

They might not all be venemous, but should all be treated as such for safety sake.

Unless you actually know the difference.

The victim hasnt moved for 24 hours and is kind of stiff..............Im not sure.Ill give it another day, its only the Wife anyway!

[Craig krup]

Producing venom is not getting something for nothing. The biological cost is sufficient that some venomous species make efforts to conserve venom. For instance, it is more dangerous to be bitten by an immature fer de lance than an adult because the adults conserve venom by injecting less of it. Some previously venomous species of snakes have lost the ability to produce venom as their prey species have changed. The very fact that venoms are not universal implies that there is indeed a biological cost involved. In biology everything has a cost. It's just harder to observe such costs.

Lactose tolerance also incurs costs. For example, lactose tolerance is associated with higher incidence of celiac disease. Lactose tolerance developed with the agricultural revolution as the reduction of meat in the diet meant that farmers had to get vitamin D from a new source, milk.

That's the thing - I can't believe the biological cost is that high. I mean, in terms of calories what's actually involved compared to (say) moving? You'd think venom was a "forced move". Once you've hit the speciation "fork" and lost your legs you'd think anything with venom would out-compete, and you'd think (if saliva can become progressively more manky and dangerous) that there would be multiple routes to being venomous.

[Craig krup]

why aren't all snakes non-venomous?

why aren't all animals venomous?

why can't all animals fly?

......on the origin of species...... good read

But the point is that 1) there's a route from saliva to venom that some took, so you'd think others could selectively evolve their way to it, and 2) given that the snakes are competing for the same rats you'd (again) think the venom gang would displace all others.

Leaving aside the question of speciation - why some lizards ditched their legs because they were enough of a nuisance in tunnels to make it a net gain - why (that move made) wouldn't a species develop venom or be out-competed by those that did?

[kannot]

why aren't all snakes non-venomous?

why aren't all animals venomous?

why can't all animals fly?

......on the origin of species...... good read

But the point is that 1) there's a route from saliva to venom that some took, so you'd think others could selectively evolve their way to it, and 2) given that the snakes are competing for the same rats you'd (again) think the venom gang would displace all others.

Leaving aside the question of speciation - why some lizards ditched their legs because they were enough of a nuisance in tunnels to make it a net gain - why (that move made) wouldn't a species develop venom or be out-competed by those that did?

ah but its a process and maybe in 20 million years there will be no venomous snakes

[csabo]

Why didnt snakes grow bigger brains and make guns, depends on their prey, if you want to get REALLY stupid you could say "god" ( refuse to use capital letter) made them that way.

Exactly "god of the gaps". If a question cannot immediately fully explained by the feeble minded then "god did it".

[slipperylobster]

My horse was asking that very same question...

Edited November 25, 2015 by slipperylobster

[gandalf12]

It depends on the way they kill their prey. A constrictor crushes its prey so it doesnt need venom but a viper doesnt have that capability so venom is its kiiling method

[Liquorice]

why aren't all snakes non-venomous?

why aren't all animals venomous?

why can't all animals fly?

......on the origin of species...... good read

But the point is that 1) there's a route from saliva to venom that some took, so you'd think others could selectively evolve their way to it, and 2) given that the snakes are competing for the same rats you'd (again) think the venom gang would displace all others.

Leaving aside the question of speciation - why some lizards ditched their legs because they were enough of a nuisance in tunnels to make it a net gain - why (that move made) wouldn't a species develop venom or be out-competed by those that did?

ah but its a process and maybe in 20 million years there will be no venomous snakes

The wife's venom is worse than any snake, and she's only been evolving for 44 years

[jacksam]

This OP might make it to the finals of the most stupid 2015. Mind you stiff opposition. First of all does the same apply to the sea dwellers. They have not lived close to humans. Ask Steve about mantra rays. Take a bite on a puffa fish.

As for snakes. The little brown small head Aussie snake won't give you much time to scoot to hospital. Snakes been around before mankind was a thought in a pair of jocks

[does]

He's probably talking to himself.

Is it me that's really stupid or is the poster really clever?

[Foxy52]

Evolution

[MILT]

why aren't all snakes non-venomous?

why aren't all animals venomous?

why can't all animals fly?

......on the origin of species...... good read

https://www.youtube.com/results?search_query=pink+floyd+animals+pigs

[expatbrit]

Each life form on earth has evolved and adapted to its own needs and environment.

Why not ask why Polar Bears are big, fierce and have white fur whilst the Hippopotamus, who is also big and fierce has no fur ?

Why do humans have differing racial characteristics ?

Why do big fish eat little fish ?

[thailanddogerator]

Because it's hard to get antivenin online ?

[Stevemercer]

Many snakes are small and fast and have lost their ability to produce venom simply because they don't need it to immobilise their prey (e.g. eating small lizards and frogs) and don't need it to stop predators (because they live in long grass or other habitat where they are hard for to catch). Over thousands of generations they have simply lost their ability to make venom because snakes born without venom can survive and breed equally well as snakes with venom. Over time the snakes without venom become a dominant new species.

Many non-venomous and non-constricting snakes in Thailand are very quick and aggressive when cornered (e.g. racers and rat snakes). They can strike and bite you 10 times in a few seconds. Whether its venomous or not, you just want to get away while it escapes.

[fakename]

Well, I think its an interesting question, and interesting discussion. Much better than "where can I get the cheapest beer sing!

[Craig krup]

This OP might make it to the finals of the most stupid 2015. Mind you stiff opposition. First of all does the same apply to the sea dwellers. They have not lived close to humans. Ask Steve about mantra rays. Take a bite on a puffa fish.

As for snakes. The little brown small head Aussie snake won't give you much time to scoot to hospital. Snakes been around before mankind was a thought in a pair of jocks

Let's compare my psychometric test scores and educational qualifications with yours for money

[Craig krup]

Each life form on earth has evolved and adapted to its own needs and environment.

Why not ask why Polar Bears are big, fierce and have white fur whilst the Hippopotamus, who is also big and fierce has no fur ?

Why do humans have differing racial characteristics ?

Why do big fish eat little fish ?

I think you're missing the point. There's a genus - snakes. Some have characteristic "x" and some don't. Basic evolutionary theory tells you that if something's a straightforward win it should spread. If it doesn't spread that's because i) it can't, or ii) there's a countervailing pressure in the opposite direction. So given that - you'd think - there isn't much of a price in being venomous, and there are obviously multiple routes to becoming venomous, and given that it seems to be useful, they should all pretty much be venomous. That tells you that in fact there has to be - despite appearances to the contrary - a pressure in the opposite direction. Being venomous has to have a cost attached to it. Someone suggested that it's a straightforward biological/calorific cost, but I find it hard to believe that that's true. My suggestion is that maybe being a threat to humans gets you killed, which is why "stand up and be seen, rattle and hiss" spread. It might also be why biologists are mistaken when they say "Non-venomous evolved to look like the venomous to avoid being messed with". Maybe, in fact, the venomous evolved to look like the non-venomous to avoid being killed.

[aronp1]

Why didnt snakes grow bigger brains and make guns, depends on their prey, if you want to get REALLY stupid you could say "god" ( refuse to use capital letter) made them that way.

Or you could call him by his real name and say "Constantine the Great"

made them that way.

[expatbrit]

Each life form on earth has evolved and adapted to its own needs and environment.

Why not ask why Polar Bears are big, fierce and have white fur whilst the Hippopotamus, who is also big and fierce has no fur ?

Why do humans have differing racial characteristics ?

Why do big fish eat little fish ?

I think you're missing the point. There's a genus - snakes. Some have characteristic "x" and some don't. Basic evolutionary theory tells you that if something's a straightforward win it should spread. If it doesn't spread that's because i) it can't, or ii) there's a countervailing pressure in the opposite direction. So given that - you'd think - there isn't much of a price in being venomous, and there are obviously multiple routes to becoming venomous, and given that it seems to be useful, they should all pretty much be venomous. That tells you that in fact there has to be - despite appearances to the contrary - a pressure in the opposite direction. Being venomous has to have a cost attached to it. Someone suggested that it's a straightforward biological/calorific cost, but I find it hard to believe that that's true. My suggestion is that maybe being a threat to humans gets you killed, which is why "stand up and be seen, rattle and hiss" spread. It might also be why biologists are mistaken when they say "Non-venomous evolved to look like the venomous to avoid being messed with". Maybe, in fact, the venomous evolved to look like the non-venomous to avoid being killed.

The "genus" contains some eighteen families "sub species) each family is further divided !

Some venomous, some are constrictors ect

There are even "snakes" which are blind ( typhlopida ?)

Perhaps you can tell us what evolutionary advantage a blind snake has?

[Stevemercer]

A blind snake lives underground and doesn't need eyes to breed and multiply. Eons ago these snakes moved underground and gradually lost eyesight because eyes did not confer any evolutionary advantage (e.g, it make no difference to successful breeding). The use it or lose it principle will always apply over enough generations.