Signs that a river otter is orphaned: Baby river otters need their mother for at least five months, but usually stay with their mother up to a year. If a baby river otter is without their mother, give the mother some time to return to the baby. If the mother does not return to retrieve the baby, the baby is weak or thin, if the baby shows any signs of injury or illness, or the mother is clearly dead, contact a wildlife rehabilitator.