And in a related story, you apparently get wet when you jump in a lake...

from the Telegraph:
Babies not as innocent as they pretend

Behavioural experts have found that infants begin to lie from as young as six months. Simple fibs help to train them for more complex deceptions in later life.

Infants quickly learnt that using tactics such as fake crying and pretend laughing could win them attention. By eight months, more difficult deceptions became apparent, such as concealing forbidden activities or trying to distract parents' attention.