Interfaith Group

It seems to me to imply that such emotions must be dependent on a belief in a 'higher power' or the related concept of an afterlife. It's more likely they simply feel the loss and 'honor' the dead -- or are offering things so they'll wake up.

Many animals have a culture. Many are more intelligent than most give them credit (crows even recognize individual human faces). Knowing a member of their group is dead, and acknowledging it, is hardly religious. Even atheist humans might honor a lost one in a similar manner as the examples given f/ animals. It's a tribute, not a belief in supernatural entities.