Amazon River Dolphin
Credit: Tony Martin

The Amazon river dolphin (Inia geoffrensis) is a freshwater river dolphin that is not only found in the Amazon River, but also in the Orinoco River, as well as the Araguaia/Tocantins River systems of Brazil, Bolivia, Peru, Ecuador, Colombia and Venezuela. Scottish researchers learned that male Amazon river dolphins sometimes carry natural objects, such as sticks and rocks, in their beaks, then throw them or thrash them against the water's surface, possibly to impress females.