Who Am I?

1. I have slick fur that is waterproof. I have large flippers. Who am I? (sea lion)
2. I have four legs. I can eat 50 pounds of meat. Who am I? (lion)
3. I can sleep standing up. I sleep 3 hours a day. Who am I? (horse)
4. I breathe through a blow hole. I communicate with sounds people cannot hear. Who am I? (dolphin)
5. I have four legs. I am the tallest mammal. Who am I? (giraffe)