There are lots of bipedal critters -- kangaroos and birds, for instance. Most great apes are semi-bipedal. What do you mean by "thinks rationally?" If you mean "capable of planning and executing those plans" then wolves and killer whales could be considered rational, as could any number of apes and monkeys. As for showing emotions, just about any higher animal out there shows emotions at one time or another. Birds get excited (at least my cockatiels do), dogs get angry or happy, etc.
No, I mean capable of planning and executing plans without being constrained by their genetic limitations. A wolf, for example, by definition lives in a den -- it can never train itself to create a spider web to catch a deer. In fact, it can never train itself to do anything.