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
Mara (mammal) Mara (mammal) The maras ("Dolichotis") are a genus of the cavy family of rodents. They are the sole extant representatives of the subfamily Dolichotinae. These large relatives of guinea pigs are common in the Patagonian steppes of Argentina, but also live in Paraguay and elsewhere in South America. Maras are the fourth-largest rodent in the world, after capybaras, beavers, and porcupines, reaching about in height. Two species of maras are recognised, the Patagonian mara ("Dolichotis patagonum"), and the Chacoan mara ("Dolichotis salinicola"). "Dolichotis" means ‘long-earred’ (from ‘long’ + ‘ear’) in Ancient Greek. Maras have stocky bodies, three sharp-clawed digits on