
How Placental Mammals, Like Whales and Humans, Evolved Bigger Brains and an Evolutionary Advantage
Key Takeaways on Placental Mammals Placental mammals have a placenta, an organ that develops during gestation and bridges mother and fetus. The placenta provides nutrients to the fetus to develop in the womb, protecting the baby from the outside world until they are fully developed. While we don’t know the first placental mammal for sure…