I do think they mourn. One of my sisters had two dogs. They never really seemed to get along with each other and pretty much stayed apart. When the Shepherd mix passed away, the Corgi mix was clearly missing her presence. He would walk around the house as though he couldn't find a place for himself. The Shepherd was the one who stayed upstairs when everyone went to bed and the Corgi stayed downstairs. After she died, the Corgi became the upstairs dog.
It was sad to watch him walking around looking for her. Not too long after that, he was diagnosed with cancer that had metastasized everywhere and he had to be put down.
Yes they do (in their own way). It took nearly a year before my dad's cat would stop blaming me for his death (he saw me help the paramedics who then put him into an ambulance). He stopped being frisky, didn't eat well and spent a lot of time sulking under the bed (this cat never liked being under a bed). Then his 'big brother' (a cattle dog) died. That cat was never the same after that.
Three nights ago, I left my bedroom window open to let in some cool air. Around midnight, I woke up and noticed my television had shut off as it will do after a few hours. It was very quiet. Suddenly, I heard the sound of some fighting animals outside in the wooded area behind my house. It sounded sort of like cats fighting but different. I looked out into the darkness and the noise seemed to be coming from up in the trees. Probably those damn buzzards, I figured. The racket continued for a minute. Then the most unusual sound came from the woods ------- it sounded like hundreds of wimpering puppies. I've never heard anything like it. It musta been birds since there aren't hundreds of puppies back there. It sounded like mornful cries, and hundreds of them.
I think most all animals , birds have great empathy for the humans of other critters they have to live with...
My dads friend had a huge Rottweiler that use to growl softly if ever I put my head close to hers...it scared me a bit at first until I realised she was purring like a cat....She was actually the gentlest dog I've ever seen...she would pick up small birds in her mouth and never hurt them...She did the same with hedgehogs and her baby hoglets would give chase and the honking they made was really loud.....lol
Rottweilers used to be called "Nanny Dogs" because they were so often used to guard children. All canines are pack animals and social. Idiots training dogs to fight give breeds bad names.
She was the soppiest and gentlest dog ever...... She would often chafe about like a Bull playing.....her to go use to hang out of her mouth as she ran about...
She lived for seven years plus and died of cancer....When she was a tiny pup, I would put my feet on a pouffe and the pup climb on to and always end up pushing my feet off.....as she got bigger ,more and more of her began to hang off the pouffe antil she got far to big......lol
I wouldn't go as far as saying they mourn in the way we know, certainly not the loss of another species, but it is common for domestic pets to pine for the missing human or companion pet.
Yes, they absolutely mourn. I've seen it in both pets and wild animals. My brother had horses and when he died I got the horses and they were obviously sad about it. I've also seen a group of geese standing by a dead goose in the road. It looked like they were crying for the dead goose.
One must be careful about projecting human emotions onto other creatures. I have seen trees and bushes do similar things. I mean if you have the imagination to see it.