Week 23: your baby is the size of a coconut crab

Your fetus is now the length of a coconut crab's body, around 30 cm (the biggest reach 40), though with its legs out that animal spans closer to a metre. It is the largest land arthropod alive, and it is really a hermit crab that outgrew the need for a shell.

It climbs trees, and it has the strongest pinch measured in any crustacean, enough to crack a coconut. It breathes air through modified gills and will drown if held underwater, yet its young begin life as plankton drifting at sea.

It hunts by smell, can live past forty, and is found only on islands scattered across the Indian and Pacific oceans, mostly ones without people.

Meanwhile, inside you

Your fetus this week is putting on weight and their skin, though still wrinkled and red, is beginning to fill out. Their inner ear is now developed enough that they may be able to sense which way is up.