Dogs do not have many advantages over people, but one of them is extremely important: euthanasia is not forbidden by law in their case; animals have the right to a merciful death.
For me, it’s always been cats, but this holds true for both. We are kinder to our animal-children than we are to other people. We don’t make our beloved companions live it out through the bitter end, because we love them. But we (not me, but many people) think humans—dying of cancer, for example—should live through every last horrific moment until the cancer kills them.