From what I understand the body loosens again after it stiffens. Just takes about 12 hours or so. Luckily I was right there when he (my dog) passed so I was able to wrap him up in a nice position to bury him that evening. I usually find a box my cat will fit snug into and curl them up so they look like they are sleeping that way they will stay in that position for when I go to bury them. I like to bury my animal friends at sunset, regardless of when they pass. I had a cat that was hit by a car and I didn't find him for a couple days. He wasn't that stiff but holy cow did he stink. One of the worst smells ever. All dogs go to Heaven.