Tongues are important, biologists say. Two recent studies explore tongue design and function--how they are used for lapping by dogs and for nectar retrieval by hummingbirds. Margaret Rubega, of the University of Connecticut, explains how hummingbird tongues, without any muscle, grab liquid. A. W. Crompton and Catherine Musinsky, of Harvard University, and Crompton's dog Matilda, demonstrate how dogs get water in their mouths by flattening the tongue into a plate and how the liquid travels through the mouth.