Infant swimming...
Is the phenomenon of human babies and toddlers reflexively moving
themselves through water and changing their rate of respiration and heart
rate in response to being submerged. The slowing of heart rate and
breathing is called the bradycardic response. It is not true that babies are
born with the ability to swim, though they have primitive reflexes that
make it look like they are. Babies are not old enough to hold their breath
intentionally or strong enough to keep their head above water, and cannot
swim unassisted.
Most infants, though not all, will reflexively hold their breath when
submerged to protect their airway and are able to survive immersion in
water for short periods of time. Infants can also be taken to swimming
lessons. Although this may be done to reduce their risk of drowning, the
effects on drowning risk are not reliable. It is extremely important to note
that while babies can imitate swimming motions and reflexes, they are not
yet physically capable of swimming.