What marine mammal is a natural at making deals and closing sales?

Which rodent is known for always carrying its little ones in a built-in pocket? Solve the riddle → What spiky animal is always perky and full of life? Solve the riddle → Which bird is almost always served between two slices of bread, but never actually flew into the kitchen? Solve the riddle → I'm a huge, grey animal, famous for the single horn that sits right upon my nose. What am I? Solve the riddle → Which fish is famous for its low notes? Solve the riddle →