Grace always loved animals. When we first met in November 1997, her circumstances weren’t really conducive to keeping pets, so she didn’t have any. But I had my cat, Sheena, and Grace was quite fond of her. After she died in the summer of 2000, we had no pets for two years, but Grace talked often about the other pets she’d had in her life, including dogs, pigs, and a half-bobcat named Louie whom she had really loved. So I wasn’t surprised when she wanted another cat; that was Aeryn, who came to live with us in the first week of July, 2002 (and only passed away two years ago). Once we moved to Oklahoma late that same year, we started collecting other animals: dogs, chickens, livestock, etc. In March of 2016 she found a tiny lost kitten literally in the middle of the road in the town nearest our ranch; that was Speck, whom you see in this picture cuddling with Annie. It wasn’t only our pets she was good with; other people’s pets gravitated to her, including the ones their owners claimed were unfriendly. Even wild animals, especially birds, would approach her a lot more closely than I’ve ever seen them approach anyone else; I used to tease that she was like Snow White.
Speck had always been much more closely-bonded with Grace than is typical for cats, but almost a year ago she started demanding Grace’s attention, habitually sitting on Grace’s desk right next to her computer, and vocally expressing her displeasure if Grace wasn’t holding or petting her. And now, in retrospect, I wonder if she didn’t know that something was wrong. The throat infection that led to the diagnosis of her cancer first appeared last summer, but the doctor who diagnosed it told us the infection had been caused by the cancer’s rapid growth; it therefore seems very likely that it was already present last spring, and altering her biochemistry enough that animals could smell the change even if humans couldn’t. I don’t recall any similar change in the dogs’ behavior, but the day after Grace’s death Annie started whining to go outside 7 or 8 times a day rather than her usual twice, and once let out she would run around the paddock for a long time as if looking for something; she only stopped doing that a couple of weeks ago. Given that Annie is a dedicated people-puppy who enthusiastically greets any friends who come to visit, I have to wonder if she wasn’t looking in her little doggy way for Grace, who was previously almost never absent for more than a few minutes unless I was as well.
Maybe I’m being silly; maybe my grief is causing me to try to find some kind of order and meaning in the loss of my loyal companion. But is it so farfetched to believe that Grace had such a close bond with animals that they reciprocated in kind, and mourned her passing in their own, albeit nonhuman, fashion?

You’re quite entitled to be a little silly about this or that while grieving, dear lady.
You are correct that animals mourn for people and other animals, just look at elephants and even dolphins.
I have seen this in person.
Not far-fetched at all. When my father passed the dog was looking for him for a while.
I do believe pets need the experience of a funeral as much as humans do, particularly because they cannot be told about someone’s passing the same way that a human can. Yes, it will be incredibly sad to see them realise what has happened to their seemingly-asleep human companion. But that’s what all funerals are. It would help them get closure the same way that it helps us get closure.