This meant that certain distinguishing features, such as mammary glands, were not obvious. The platypus was ultimately placed into a new order called Monotremata, alongside the four living species of ...

Reproduction among all mammals is similar, in that all have internal fertilization and females nourish their young on secretions of mammary glands. Differences in ... vented through a single opening ...

Reproduction among all mammals is similar, in that all have internal fertilization and females nourish their young on secretions of mammary glands. Differences in ... vented through a single opening ...