Before cuttlefish embryos even hatch, they look through their translucent eggs to learn to identify their future prey. Researchers at the University of Caen Basse-Normandy put crabs in a tank with cuttlefish eggs. Once the cuttlefish hatched, they were released into a tank with both shrimp and crabs. The cuttlefish that previously saw the crabs through their eggs had a taste for them. Cuttlefish that weren't exposed to the crabs as embryos preferred to eat the shrimp. From the BBC News:
…Unborn cuttlefish… have fully developed eyes. That leads the researchers to conclude that the cuttlefish embryos must peer through their eggs, and learn to recognise their prey, a behaviour which will help give them a head-start in life.
It is less likely that birds, reptiles and, particularly, mammals – including humans – could recognise visual images in the womb.
But the cuttlefish discovery helps reinforce the idea that some animals at least can begin to learn before they are born.
Link (Thanks, Greg Benjamin!)