“They [cats] engaged less in sleeping, eating and playing but more in seeking attention from humans and other pets, hiding, spending time alone and appearing to look for their lost companions,”

My old cat and dog used to fight constantly. One day we had to put down our dog and the cat howled for days cause his sparring partner was suddenly gone. Whether the cat was lonely or legitimately grieving, I couldn’t say, but the experience certainly was eye-opening.