Oceans are the largest animal habitat on the planet. The oceans are so huge that they cover more than 70% of the surface of the Earth. Fish and other animals make their homes in all parts of the ocean, even on the bottom. The oceans are home to some of the planet's most unusual creatures. The oceans are also filled with lots of plants, which provide food and homes for the animals. Even though the open seas are so big, it is estimated that only ten percent of the world's animal species live there.