The most 4 rarest kangaroos in the world. Discover animalzoid 644 1 The most 4 rarest kangaroos in the world. Do you know that Kangaroos are the world’s most giant marsupials? The Kangaroo comes from the animal family Macropodidae and the class of Mammalia. The term Macropod means, in Macropodidae, “large foot”.