The dolphins also move into these areas. The boto move right in among the trees while the tucuxi stay in the deeper waters. The tucuxi's neck vertebrae are fused so they aren't as flexible as the boto and cannot maneuver between the flooded forest floor. Regardless of whether it is the dry or wet season though, the dolphins move about throughout each day. They can swim as much as 30 kilometers in any given day.
Many individuals do remain in the same general area for years however.
Both the boto and tucuxi can see above and below the water but sound is much more important to them as theriver water is often muddy which makes seeing difficult. That way they can navigate and communicate with one another even though they may not be able to see in the water. All species of dolphins use sound for echolocation. Inia and Sotalia are capable of echolocation, but very little research has been done how they use it. The average length of time that calves nurse is not known.