FruitlessFetusSign upYour fetus is the size of a sea angel, a tiny swimming sea slug that flaps a pair of wing-like flippers through cold ocean water. Adult Clione limacina are often around 3 to 4 cm, right where your fetus is now.
Sea angels are almost completely transparent, with a small orange-red core that makes them look like something a jeweler designed. They drift through Arctic and sub-Arctic seas looking, frankly, angelic.
The angel act ends at mealtime. Sea angels hunt one specific prey, a related snail called the sea butterfly, and when they catch one they deploy six grabbing tentacles that shoot out of their head to hold it still. Nature is rarely as gentle as it looks.
Meanwhile, inside you
Your fetus this week is roughly the same length but far busier: they are starting to open and close their hands, and their bones are beginning to harden.