When your dog dies, does your cat grieve? Science says yes

They added: “Many cats and dogs sharing a household were reported to sleep and play together. Therefore, cats could have also responded to losing a positive relationship with a dog as a possible interspecific ‘preferred associate.’” (This sounds like the term a cat would use when referring to a dog or possibly even its owner.)
This is something of a surprise, given that cats have been domesticated much more recently, descend from a different evolutionary branch and express themselves differently than dogs. “Whereas dogs, descended from pack animals, might reasonably respond more strongly to the death of a conspecific, cats under human care have adapted to live among conspecifics and their capacity to respond to the loss of a companion warrants further study,” they wrote.
But other studies — OK, that one other study — did also show changes in behaviour among dogs and cats alike, including attention seeking, increased time spent in the deceased companion animal’s “favourite spot,” seeming to look for the animal and, in the case of cats, louder and more frequent vocalizations following the loss.
The study had many potential pitfalls, as the researchers themselves pointed out. Caregivers might project their own grief onto their cats. They might seek comfort from the cat and thus be more likely to notice the cat’s behaviour. Or it could be that the caregivers’ grief, rather than that of the cats themselves, altered the surviving cats’ behaviours.