The tiger's expression is fantastic. I can just envision him telling his little rat friend all about his adventures that day. And she is listening so attentively. You did a wonderful job with her anatomy and pose as well! Rats can be surprisingly difficult to draw, and you nailed it perfectly. And I'm not going to lie... I'm totally jealous of the way that you draw paws! I find them challenging, and you've made them look so fluid and natural. I want to squeeze them.
You picked an excellent texture and colour scheme for the background, too. It meshes very well with the characters. I'm looking forward to printing these guys out for my wall.