What are Merlin and Pixie sharing?

My dogs are really quite good at sharing - they rarely growl or snap at each other. Today I went to the pet shop intending to get them each a marrow bone. Unfortunately they come in packs of 2 and they only had one pack left. So, two bones - four  dogs?. Knowing that Mystic doesn’t really ‘do’ bones I gave one to Merlin and the other to Sprite. Pixie was unsure what to do at first - both the ‘boys’ were really getting down to it. I was about to take Sprite’s away to give to Pixie when she calmly walked up to Merlin, smiled sweetly at him, and he simply walked away and let her have it! The extras show Pixie and Sprite enjoying their bloody bones. (I took them away and put them in the fridge for tomorrow - there was a lot of marrow in there!)