If funerary practices and writing are the criteria for animal intelligence, then I’m afraid you’ll have to wait. But I think it is undeniable that some animals have some capacity for abstract thought, and have the ability for strong emotional investment. I studied elephants in Namibia at one point and witnessed some really remarkable and moving interactions. And trust me, I’m not like that knucklehead in Alaska who thought he could commune with bears - if elephants don’t almost scare the brown out of you, I don’t want you around. But they are marvelous, intelligent creatures that provided me with well deserved doses of both humanity and humility.
I recall many years ago watching a documentary where they were trying to separate a baby elephant from its mother so that it could be transplanted to a reserve nearby but the mother resisted so strongly, the tranquilizers were not working on her. She died in the struggle. Very sad.
Likewise, I recall another documentary of a mother moose and her calf. An Alaskan brown (or grizzly, not sure) showed up in the distance. The mother pushed the calf down with her nose and ran straight towards the bear which of course killed her.
Animals are certainly capable of many amazing emotions and decisions.
But their intelligence does not rise anywhere close to humans in whatever abstraction man does such that he cherishes another enough to care for the remains and build monuments to him, remembering his life in words or pictures.