[jemmyw]

I've lost many pets over the years and my father, and grandparents I was close to. I think it depends on the circumstance. Losing a pet unexpectedly is worse than losing a grandparent to old age. A pet dying of old age is a mix of grief and relief (especially if you have to make the decision). My father died suddenly of a heart attack, that was worse than losing any of my pets, but it was a more amorphous pain, spread out over time.

We're with our pets a lot more than with extended family so it makes sense that a pet dying can be more intense than losing a friend or family member who does not live with you.