What are warm blooded and lay eggs and take care of their young?

The few mammals that lay eggs (the Platypus and the Echidna) are monotremes. They are warmblooded, produce milk and take care of their young. Most mammals are placental, give birth to live young, give milk and take care of their offspring.

All mammals are warm blooded by definition. Although the earliest mammals probably laid eggs, the only ones that do today are the spiny anteaters (echidnas) and the platypus. The platypus cares for its young by digging a deep burrow where it builds a nest, and then incubating the eggs. After the eggs hatch, she nurses the babies for 3 to 4 months. After a female echidna lays an egg, she places it in her pouch. When the egg hatches, she carries the baby in her pouch and nurses it until it grows spines. Then she digs a burrow for it. She continues to nurse it until it is about 7 months old.