Later in the afternoon, a pair of adult squirrels approached the now-cold body. The first one used her hands to sort of fluff his fur, like someone searching a drunk for change or perhaps grooming a dead sibling. When she left, the other approached and lay a stick across the deceased's chest.
If this is not a squirrel funeral, I can't imagine what else it meant.
EDIT: Good news - the one who died wasn't one of my favorites, the crazy-acrobatic one. That silly boy still leaps from tree to tree, wheee!