I don’t know how it is done but I read that when cats are stalking prey, a noise nearby produces no electrical impulse in the cat’s auditory nerve. So the cat isn’t blocking the noise out, it has effectively rendered itself deaf.
In Richard Feynman’s autobiography, he mentions discovering that he could tell by smell which book on a shelf had been recently read. IIRC, he opined that dogs might not be so much better at that job than we are; we just don’t ever really try.
I’d like to ask you to cite where you read this, because it contradicts my own experience. From what I’ve seen, cats when stalking are “on high alert” and quite sensitive to any noise or other physical change in the vicinity.
For example, when my kitten is stalking my sleeping elderly cat, if I say “stop that!” or even just make any noise, his ears immediately flick back towards me and he pauses, etc. – quite clearly he has heard me and certainly isn’t ‘temporarily deaf’.
I’d like to be able to tell you. It was many years ago and it stuck with me because the information was accompanied by a simplified drawing of a cat with a meter attached to the auditory nerve. Presumably that would have been necessary to make the stated claim. I’m fairly sure the piece was about focus and concentration and presumably refers to those last moments before the cat grabs its quarry. I know that to some extent it’s not unique, I’m sure we have all been concentrating so hard on something that we become oblivious to the world around us.
Nonetheless having made the claim I will do what I can to confirm its correctness.
You’ve got to understand just what having a sense of smell 1000 times greater than a human’s actually means. The increase is accomplished in two ways. Firstly digs have a much greater number of receptors in the olfactory membranes themselves. This allows them to pick up a lot of signals that people will miss at low concentrations. The other part of the system is the brain itself, and dogs have relatively greater areas of the brain devoted to processing olfactory information. Note that neither of these differences actually increase the intensity of any nerve signals from the nose to the brain. Nerves tend to either fire or not, and while dogs may have more nerves feeding from the nose, those nerves are interacting with the brain in exactly the same manner. When we talk about dogs being able to smell better we aren’t talking about dogs having human smell amplified like a stereo with the volume cranked up. Instead a dog and a human seem to perceive the same smell the same way within normal human ranges. When you smell skunk the dogs smells skunk almost the same way you do. However when a scent becomes to dispersed for you to notice it a dog will still be able to perceive it and because it has a greater section of the brain devoted to deciphering scent it can interpret that information. A dog can therefore pick up the subtle scents associated with skunk spray as well as the main odour, but the odour itself is no more disgusting to a dog than it is to us.
I guess the best thing to do is look at it in reverse. Your sense of sight is many times better than a dog’s at distance. For a visual object that falls within dog range, such as a full moon, you and the dog will perceive it almost the same way in broad terms. You will both see a bright disc. However the dog’s image will be blurry, and you will be able to discern subtle features such as the crater shadows on the surface. However the full moon does not blind you despite the fact that a dog can see it and your vision is many thousands of times better. Having a better sense just allows an animal to perceive more details within that sense, it doesn’t magnify everything indiscriminately.