births may take place year round, but appear to be concentrated between december to january and march to may. gestation is thought to be approximately 9–10 months. after around one year, juveniles are weaned and they reach sexual maturity at about 10 years of age. during the monsoon, south asian river dolphins tend to migrate to tributaries of the main river systems. occasionally, individuals swim along with their beaks emerging from the water, and they may "breach"; jumping partly or completely clear of the water and landing on their sides.