Is the title right? This cat is friendly with the rabbit and the rabbit is eating bunny food….with his cat mate. What is going on? The cat licks the bunny which is obviously a sign of affection and the eats (nibbles is a better description) bunny’s meal. The commentary on the video says that the cat is trying to be friendly. I’d suggest that the reason why the cat nibbles the bunny’s food is because they are close friends and the cat is simply joining in and being sociable. Domestic cats are really quite sociable nowadays. It is just possible that the cat is eating the greens to avoid upsetting his friend. That might be humanising the cat but it might not be. It is a bit strange. There is one last possible answer and it is a bit cynical. The person who made the video put something that a cat finds tasty on the greens which attracted the cat to try and eat it which looks like he is nibbling it. That would not surprise me because there is a lot of competition between videos for viewers and video makers will try almost anything to get hits.