The two species of dolphins found in the Peruvian Amazon are the pink dolphins (Inia geoffrensis) (front photo with this report) and the gray dolphins (Sotlaia fluviatillis) below. However, similar to beluga whales, pink dolphins are born gray, almost black, and loose pigmentation as they age. As can be seen in the photo, a large juvenile which is still gray in color, is swimming with its presumed mother displaying pink coloration with a touch of gray on the head. However, we are not certain of the family ties, which is part of the motivation to device a method to individually identify these dolphins acoustically…a voice recognition system! These pictures were taken during the first couple of weeks in July.
We also have documented what appears to be territorial behavior displayed by Inia towards Sotalia. Although these two species hunt for fish together peacefully at river confluences, the Inia prefer to have their resting areas free of Sotalia. We have documented the Inia actively chasing the Sotalia from the calm, shallow, protected from currents resting areas preferred by Inia on three occasions.
Maria (from Peru)