Who Tied Up the Beaver?

Beaver has been found tied and strung up a tree branch. Who could have done such a thing? Sherlcok quickly deduces that three animals who are unhappy with Beaver's recent songs could have done it. The songs criticize Crocodile, Seal and Chef Panda. During the investigation, Hermione points to the fact that Sherlock is cheap. This annoys him. He thinks he's jus thrifty.