brilliant pics!
little kids are able to not 'drown' since their systems are still not quite air'd out ( the whole gag reflect evolution ) - and the earlier you get them into the water, the better they fare longer term. Babies can swim literally from birth, but with a lot of supervision and control ( their body weight is distributed in a way that swimming on the top / surface is hard till they are past 2/3 years old - its what i think Clive is also saying ).