They are in such darkness, they are unable to see that the person at the other end of the photon stream usually only has about 3 volts of power. A dog will get sick, or slammed by a car, or just overtaken by Time, and they will use a goodly portion of their last heartbeats doing whatever they can to get home, so they can die with the comfort of someone that loves them. That's when it is payback time for the master or mistress. A cat's intrinsic dignity is much stronger than his need for comfort. When a cat knows the end is imminent, he will usually drag himself off to a dark, quiet place, and set his face towards the unknown alone.
Humans generally prefer to die accompanied by family and friends.
Then there are wakes and funerals and memorial services, but none of that ritual is for the sake of the dead. That's all entertainment for the survivors. Maybe it will be some compromise between the two. I wrote this piece a couple or three years ago, and briefly published it on my personal web site. I have dusted it off, in memory of the longest continuous friendship I've ever enjoyed.