Cat death behavior?

Sorry to be macabre here - especially since I'm new. My wife and I have 4 inside/outside cats. The oldest has been looking sickly suddenly and we haven't seen him in a day or two - very unusual. We have spent a good amount of time searching the woods behind our house for him, but the undergrowth is VERY thick. I have heard when cats know they are going to die, they find a place away from home and simply lay down and "go to sleep". Is this and urban legend or is it normal for a cat to die in the domicile it lived in. I'm clueless in these issues; we never had a cat die of old age. Thanks for any help!!

Cats are prey animals, as well as predators. If they are ill they will "go to ground" and hide so they are less vulnerable to predators. This can be a real problem for us humans who want to help them and get them medical treatment, as they are very good at hiding. It does, of course, depend on the cat. The more feral they are, the more likely they are to hide when ill.

I'll move this to Behavior for more opinions.

Yes it is true, they find a nice quiet dark place to hide and they lie down and well, they die if they can't seem to regenerate themselves.

Concerned and curious how old your cat is and what are the sickly looking signs you've been seeing?