Mammals- are animals that have warm-blood, fur or hair, and have live babies. o All mammals have some type body hair or fur. Some marine mammals are nearly hairless, like whales and dolphins. o The longest mammal gestation is a little longer than 20 months, and belongs to the Asian Elephant. o Marsupial ... , and 4 species of echidna. All live in Australia and New Guinea. These animals are very primitive mammals, sharing some physical features with birds and reptiles.