Do rabbits mourn?

So we are keeping a close eye on Jay Jay following the loss of Lucky. Di rabbits mourn. Does he wonder where she is? Lucky was a shy rabbit so we did not force her to be around us too often. J is a very confident rabbit. He spent the evening sprawled on the rug. It's Monday day was mad busy. Did a wee spin session and a wee kettlebell session. Couldn't keep my eyes open.