Your saddest animal movie?

I cried for an hour after this movie was over an it still makes me sad to even think about it :'(

Hachi: A Dog's Tale.... that was soooooo sad, idk if you would call it a sad animal film because its more about.... *****spoiler*****
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the dog loved his owner so much then he died and the dog still went to meet him *****end spoiler*****

it was just really really sad :'(