Week 14: your baby is the size of a long-eared jerboa

Your fetus is now the size of a long-eared jerboa, a tiny desert rodent whose body is only about 8 cm but whose ears are a third longer than its head. Sometimes called the Mickey Mouse of the desert, it looks almost too whimsical to be real.

It lives in the deserts of Mongolia and northern China, bouncing across the sand on long, kangaroo-like hind legs and using those enormous ears both to pinpoint insects in the dark and to shed body heat.

It was barely filmed in the wild until 2007 and remains so poorly studied that scientists still list it as a conservation mystery, a whole mammal we have only just begun to meet.

Meanwhile, inside you

Your fetus this week is starting to make facial expressions, squinting and frowning, as the tiny muscles of the face come online. They cannot control them yet, but the wiring is being tested.