Scientist Discovers First-Ever Venomous Frog the Hard Way
- Thread starter PatrickJS
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So wait... does mean there is a venom gland connected to these spines. There's an important distinction. there. Otherwise it's just a poisonous frog with a spine and aggressive butting tendencies. If teh spine is just coated incidentally with the mucus that coats the rest of the frog....FalloutJack said:
Possibly, you meant to quote the OP, but it's these weird little things that make me wonder about the whole thing.MonsterCrit said:
I wonder... I mean, given a frogs' natural prey of insects this seems like a purely defensive adaptation, right? But would this mean that unlike a regular frog which may secrete a poison, that this frog actually has a developed venom gland at the base of the spine like a snake fang? Or is it merely that the frog secretes poisonslike any regular frog, it's just that the spine creates an open wound combined with poisonous residue on its head impacting with the wounded surface?
I see the word 'inject', which to my mind conjures an image of an internal vessel filled with venom that is internally secreted upon impact as opposed to merely a secreted poison that just so happens to 'pool' about the spine waiting to seep into an open wound via impact force. But it's still kind of vague.
I see the word 'inject', which to my mind conjures an image of an internal vessel filled with venom that is internally secreted upon impact as opposed to merely a secreted poison that just so happens to 'pool' about the spine waiting to seep into an open wound via impact force. But it's still kind of vague.
An animal being venomous vs. poisonous actually has a big effect on it's behaviour.FalloutJack said:
Being poisonous actually doesn't help an individual animal at all. How cares if the thing that eats you ends up dying afterwards, you're still dead? It does protect a population of animals though as predators evolve to avoid them. So you get all the brightly coloured anti-camouflaged poisonous animals who advertise their species as their defense mechanism. As well as the animals that imitate them.
Whereas venomous animals are edible as long as the predator is careful. The venomous animal also has to develop the aggressive behaviour needed to administer the poison whether this is done for hunting or for defense.
Venom is active and poison is passive. I suppose it's analagous to the difference between ambush predators and chase predators. It might seems like an unnecessary distinction (who cares how they catch them, the point is that they eat other animals, right?) but it's actually a completely different survival tactic with different adaptations which assist it's usefulness.
In nature, poisonous beings have recognizable signs about them that animals and such realize and avoid. It's true! There could be a smell, a color, a marking - and that is why poisonous creatures remain alive.K12 said:
Are you disagreeing with my point that being poisonous doesn't help the individual organism (otherwise I have no idea why you would bother with this post) because I'm right if you think about it in terms of poison being an evolutionary adaptation that gets selected for. The behaviour of predators avoiding the recognizable signs of poisonous animals evolves in tandem (or after) poisonousness.FalloutJack said:
Poisonousness only has an effect if some animal eats/bites/licks you and then dies or gets sick and as a result makes "avoidance of animals that look like you" an evolutionary advantage (plus temporarily makes fewer predators around to eat your still living family). Animals aren't going to avoid eating a brightly coloured poisonous frog if that behaviour hasn't evolved. The bright colours evolve in tandem or after the poison so that the species is distinctive and also after the behaviour to avoid you species have evolved in potential local predators.
The reason I addressed your post because if being poisonous doesn't help out the individual, it doesn't do anything for the species either and thus has no point from an evolutionary standpoint. Because indeed...if the animals dumb enough to eat it do so anyway - thus killing the species even if it itself dies too - then that species wouldn't survive anyway. SO, because poison creation and use is certainly found in nature to prevent death or to take life, it must have ended up this way after successfully upping the survival of the species. This means that predators either recognize the poison before or during the attempt to eat, but do not manage to eat or kill the critter because of the poison. No creature on this Earth is poisonous out of spite. I know this because humans have no sting, and we're the only ones with real spite.K12 said:
This comment is wrong and the reason that it's wrong is actually quite an interesting aspect to evolutionary biology which I can't really do justice in a couple of paragraphs. The basic idea is that evolution does not select for genes that have an effect which benefits the organism, instead it selects for genes that have an effect which benefits that gene (including copies of the gene that might exist in the offspring or relatives of an organism). It isn't about an organism trying to pass on its genes, it's about genes manipulating the behaviour and characteristics of its organism(s) to make themselves more numerous.FalloutJack said:
It might well be the case that poisonousness was selected for because predators begin to eat the animal and then stopped but since poison is rarely this fast acting and the animal would be injured (perhaps even dying) I think this won't be the whole explanation (or even the biggest part of it). It's also worth being wary of the "the animal has X characteristic therefore X characteristic must have helped it survive" idea since it can lead you astray in some cases.
I suggest reading Dawkins "The Selfish Gene" if you'd like to know more about this, or if my explanation still doesn't make sense/ convince you.
Actually the Poison Dart Frog carries enough poison to kill 2,200 people. So I wouldn't say it has a mild dosage (when you consider it keeps the majority of its poison on its skin).FalloutJack said:
OT: This is somewhat cool and very interesting. This is the first animal I've heard of that uses a headbutt to inject venom into its target.
Looks like he got lucky, the other venomous frog has venom more potent than a pit viper. I would hate to be that scientist, imagine waiting five hours in pain not knowing whether the venom is lethal or not.
Especially because venom has no effect when ingested, unlike poison.FalloutJack said:
Are we? I can't see any conflict in what either of us has said... honestly, I can't even tell what point you're making here and I don't know if I want to try to work it out anymore.FalloutJack said:
I think this is going to be the last comment I post to you on this thread. I've made my point as best as I can (in short form anyway) and I don't see any value in making it again.
Ah, well the point against your point - whether you care to acknowledge it or not - is that the poisonous frog is way too toxic to be eaten, and the barb just imparted that succinctly. So, yeah. Sorry.K12 said:
You can pay me back by explaining to the nice people that I wasn't being a jerk, but generating discussion value, which I did.PatrickJS said:
Here Jack, this is a pretty solid article on the toxic nature of the poison dart frog and why they evolved that way.FalloutJack said:
http://www.bbc.com/earth/story/20150422-the-worlds-most-poisonous-animal
Also I need to amend my previous statement to say that 2,200 people is over the life time of the frog, at any give time it is 10-20 people (which is still pretty toxic). Birds and natural predators of frogs tend to learn very quickly to avoid the frogs when introduced to a new area, so it is a very effective defense.