This is the sort of thing I think about
Nov. 16th, 2006 06:22 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
farlaSo where I am there are a lot of squirrels. They're pretty calm about people, but they aren't at the stupid level where you can walk right over and grab one yet.
I like squirrels. I don't care how commonplace they are, that's just a bonus. I'll keep walking in whatever direction I'm going, but I'll turn my head to stare at them the whole time until about the point I'd have to walk backwards to continue.
There are two responses to this. Response A is "It doesn't notice me, I'll just ignore it." Squirrels can be rather clever, though, so most of them understand that turning my head means I see them, so they go to Response B: "Freeze in place so it can't see me."
A lot of people think this response is idiotic, and with good reason. It means that you have several chances to sneak up on it and as long as you want to call your friend over to help you ambush it. I have fond memories of chasing rabbits all over the woods. Those rabbits were way faster than a ten year old kid dodging brambles, but they never just bolted. They bolted ten feet and froze in place. And yes, this was a really effective defense. Rabbit fur is identical to leaf litter. If you haven't seen this, there aren't words to properly describe how perfect this is. You cannot see the rabbit. It is no longer there. But if you stare at where it was, you can eventually make out a rabbit-shaped outline and a black spot that's an eye, and then rush it again. You can do this for hours with the same rabbit, because it will never just keep running.
Now, if a lowly human kid can manage this, then something like, say, a dog, with its incredible sense of smell that's a real hunter should have no problem, right?
But these weren't baby rabbits. They were adults who had somehow survived this long. Either they had learned to do this because it worked, or it was instinct, and instinct could only evolve if it was actually helpful.
See, dogs will run about like idiots trying to figure out where the smell is. They won't lunge anything until it moves, at which point they do so regardless of smell (think frogs). Dogs are dumber than wolves, so I can't say how extreme this is among the non-kibble eating population of carnivores, but motion is definitely a major requirement.
In most of the animal kingdom, freezing in place works. It makes prey invisible.
Human eyes are better, then. Not just better than a dog's, but better than a large portion of predators. We often have this sense that we're some sort of weaker animal because we can't match a given animal's feats, but it's oddly untrue.
This might be some sort of artifact - humans were originally eating fruit, fruit doesn't move. But we have color vision for fruit. We didn't need a good enough sense of contrast to pick out the slight irregularity where rabbit fur met leaf. Besides, while evolution often works by one thing taking on a new use, it seems odd that we'd have such exceedingly good eyes for something unrelated.
One of the things I learned when I was a kid was that people used to think humans had evolved big brains, then stood up. (When my parents showed me 2001: A Space Odyssey, my mother took the time to explain during the opening.) The newer theory is we stood up first, allowing us to free our hands. With our hands free, we could start doing things with them, which let us get more food (carrying it back) which allowed more complex brains and gave us incentive to develop our brains to think up new ways of using our hands. More recently, I heard that it was, again, standing up that did it, but that the important thing was that we could walk to carcases and eat meat, which gave us enough energy to start running a larger brain. See, our brains require an incredible amount of energy to maintain, which is why they could only develop after some other hurdle was passed.
But so do eyes. Our eyes are also nerves and they're incredibly costly to run. When you're stressed, they're pretty much the first thing to go - that's where things like tunnel vision come from.
So I'm thinking eyes must have had some play in whatever the developmental path was. Most of the things that happened to the homo line were flukes of sorts, kind of unprecedented in terms of fellow animals, and it's only all of those things together that allowed us to get to where we are today. I wonder if eye development might have been an important factor too. Otherwise, you'd think they'd have gone the same way as our jaws to make room for more brain tissue.
I like squirrels. I don't care how commonplace they are, that's just a bonus. I'll keep walking in whatever direction I'm going, but I'll turn my head to stare at them the whole time until about the point I'd have to walk backwards to continue.
There are two responses to this. Response A is "It doesn't notice me, I'll just ignore it." Squirrels can be rather clever, though, so most of them understand that turning my head means I see them, so they go to Response B: "Freeze in place so it can't see me."
A lot of people think this response is idiotic, and with good reason. It means that you have several chances to sneak up on it and as long as you want to call your friend over to help you ambush it. I have fond memories of chasing rabbits all over the woods. Those rabbits were way faster than a ten year old kid dodging brambles, but they never just bolted. They bolted ten feet and froze in place. And yes, this was a really effective defense. Rabbit fur is identical to leaf litter. If you haven't seen this, there aren't words to properly describe how perfect this is. You cannot see the rabbit. It is no longer there. But if you stare at where it was, you can eventually make out a rabbit-shaped outline and a black spot that's an eye, and then rush it again. You can do this for hours with the same rabbit, because it will never just keep running.
Now, if a lowly human kid can manage this, then something like, say, a dog, with its incredible sense of smell that's a real hunter should have no problem, right?
But these weren't baby rabbits. They were adults who had somehow survived this long. Either they had learned to do this because it worked, or it was instinct, and instinct could only evolve if it was actually helpful.
See, dogs will run about like idiots trying to figure out where the smell is. They won't lunge anything until it moves, at which point they do so regardless of smell (think frogs). Dogs are dumber than wolves, so I can't say how extreme this is among the non-kibble eating population of carnivores, but motion is definitely a major requirement.
In most of the animal kingdom, freezing in place works. It makes prey invisible.
Human eyes are better, then. Not just better than a dog's, but better than a large portion of predators. We often have this sense that we're some sort of weaker animal because we can't match a given animal's feats, but it's oddly untrue.
This might be some sort of artifact - humans were originally eating fruit, fruit doesn't move. But we have color vision for fruit. We didn't need a good enough sense of contrast to pick out the slight irregularity where rabbit fur met leaf. Besides, while evolution often works by one thing taking on a new use, it seems odd that we'd have such exceedingly good eyes for something unrelated.
One of the things I learned when I was a kid was that people used to think humans had evolved big brains, then stood up. (When my parents showed me 2001: A Space Odyssey, my mother took the time to explain during the opening.) The newer theory is we stood up first, allowing us to free our hands. With our hands free, we could start doing things with them, which let us get more food (carrying it back) which allowed more complex brains and gave us incentive to develop our brains to think up new ways of using our hands. More recently, I heard that it was, again, standing up that did it, but that the important thing was that we could walk to carcases and eat meat, which gave us enough energy to start running a larger brain. See, our brains require an incredible amount of energy to maintain, which is why they could only develop after some other hurdle was passed.
But so do eyes. Our eyes are also nerves and they're incredibly costly to run. When you're stressed, they're pretty much the first thing to go - that's where things like tunnel vision come from.
So I'm thinking eyes must have had some play in whatever the developmental path was. Most of the things that happened to the homo line were flukes of sorts, kind of unprecedented in terms of fellow animals, and it's only all of those things together that allowed us to get to where we are today. I wonder if eye development might have been an important factor too. Otherwise, you'd think they'd have gone the same way as our jaws to make room for more brain tissue.
