Mammals of Australia introductions of placental mammals into Australian fauna were about (rats), several thousand years ago (dingo), and 200 years ago (many species); the last two were made by humans. Some claims were made about placental mammal fossils from the Eocene of Australia, called "Tingamarra". These claims are based on only one found tooth having some characteristic features of condylarth, and were discussed widely. But both the age and placental nature of these fossils were challenged by other researchers. Monotremes are mammals with a unique method of reproduction: they lay eggs instead of giving birth to live young. Two of the five
Eastern long-beaked echidna of this species. Humans are the main factor in diminishing populations of eastern long-beaked echidnas. Locals in areas surrounding regions that these organisms inhabit often prey upon them for food. Feral dogs are known to occasionally consume this species. These mammals dig burrows, providing some protection from predation. Factors of deforestation also impact this species negatively. There are four isolated subspecies that inhabit specific geographical regions. The eastern long-beaked echidna is a member of the order Monotremata. Although monotremes have some of the same mammal features such as hair and mammary glands, they do not give birth to live young,