Cuttlefish are the only species of animal known to engage in pre-birth visual learning. A study by Anne-Sophie Darmaillac showed that, while still inside their transparent eggs, embryonic cuttlefish identify their future prey according to the species they see in their immediate environment. Although shrimps are their instinctive food preference, the embryonic imprinting process will persuade a cuttlefish to choose crab instead, if that is what it saw from inside its egg.