(August 28, 2016 at 2:43 pm)Yoo Wrote: Hi everyone! This is my first thread on this site, and I'm starting small.
I just had a thought today, thinking about venomous animals.
Why is the venom of some animals, like certain kinds of spiders and scorpions, strong enough to kill even a human?
Surely they don't need venom that strong for their prey, which is not much bigger than mice I'd say, so that can't be the reason. I find it hard to believe that it's for self defence, because the venom doesn't kill or weaken the threatening predator fast enough for it not to be able to kill its prey.
Maybe these sorts of questions shouldn't be on here, because they're too specific, but I'm curious and maybe some of you find this interesting as well.
(English isn't my first language so don't kill me for getting words wrong 'n stuff)
Edit: The question has been answered, but the discussion is now about how an evolutionary arms race could have started.
Another question!
You know those flashy colored frogs? Poisonous animals often have very distinct colors, this has been interpreted as a warning to predators. There are even 'fake' ones, that aren't even poisonous, but do have the flashy colors to put off predators.
The first poisonous animals probably were poisonous out of self protection, like those frogs we see today. Now let's focus on the moment where those animals got flashy colors. I can't really think of how a poisonous animal would benefit from showing its poisonness to predators. Your first reaction might be: That way predators know it's poisonous, so they won't eat it.
I have a problem with that simple explanation, because: the first poisonous animal that showed its poisonness to predators was, obviously, the first one. The predators had no built-in mechanism for avoiding that particular 'warning sign', so they wouldn't refrain from eating it. You might say that the color might have just put the predators off, but simply being brightly colored doesn't usually put predators off. Then we would probably see a whole lot more brightly colored animals, like bright-green rabbits or something. And of course bright colors in animals are usually accompanied by some kind of venom. So why did the bright colors evolve?
I also don't get why being poisonous for self defence can you anywhere at all as an insect, because who cares if the predator dies or not AFTER eating you?
1. There are many plausible ways for a small animal to evolve venom strong enough to kill a human: One that comes to mind is the poisonous animal needs the venom to be strong enough to act very quickly on its normal target. The strength sufficient to kill a small animal in a few seconds might also happen to be enough to kill a much larger humans in hours or days.
2. if a predatory isn't adopted to recognize a flashy display as a sign of lethal poison, then obvious the flashy poisonous prey is even more screwed then a non-flashy, ordinary prey. But the predatory is also screwed. So predators are preferentially selected to avoid flashy prey. This selection of the predatory then allows flashy prey to preferentially survive. This is how flashy prey evolves. Not because the first hint of flashiness immediately benefit its wearer. Instead, a certain distinguishing feature from all other prey that allows predators to become condition to recognize one from another and force predatory to evolve poison avoidance instinct. This is what over long periods allow poisonous prey to slowly evolve signatures that makes it gradually easier for predator to tell it from another.
