Why do lions roar? Why do crickets chirp? Why do bucks shed their antlers every year? How can porcupines and hedgehogs avoid poking themselves? Do fish pee? What is the fastest fish? What do jellyfish eat? A roundup of animal questions, with answers from Paola Bouley of Gorongosa National Park in Mozambique, Kent McFarland of the Vermont Center for Ecostudies, naturalist Mary Holland and Jo Blasi of the New England Aquarium.