There are very low numbers of dolphins left like: >The Common dolphin has only 179,000 in the world >The Striped dolphin has only 485,000 in the world >The Spotted dolphin has only 782,000 in the world It is a relatively abundant freshwater cetacean with an estimated population in the tens of thousands. Together with Monodontidae (narwhal and beluga whale) and Porpoises (phocoenidae), oceanic dolphins belong to the Delphinoidea superfamily. Some species' populations are known but no one has estimated the total for all dolphins. Māui dolphin or popoto (Cephalorhynchus hectori maui) is a subspecies of the Hector's dolphin (Cephalorhynchus hectori)—New Zealand's only endemic cetacean species. A dolphin pregnancy last between nine and 16 months. Dolphins are marine mammals. It is found throughout much of the Amazon and Orinoco river basins in Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela. The mother feeds her offspring on milk. There are currently 42 species of dolphins and seven species of porpoises. Oceanic dolphins vary in size from 110 pounds and 5.6 feet long (Maui’s dolphin… There are at least 36 known species of dolphins and a few more different subspecies. There are approximately 30 extant species of oceanic dolphins, including several species that are often mistaken for whales. Top ten dolphin facts. They must surface to breathe air and give birth to live young. Oceanic dolphins are a widely distributed dolphin family which resides in the sea. The Amazon river dolphin, also known as the pink river dolphin or boto, lives only in freshwater. There are at least 44 species of dolphins divided into oceanic and river families and they are found in waters all over the world. https://www.dolphinproject.com/resources/about-dolphins/types-of-dolphins According to the IUCN Red List, 5 species and 6 subspecies of dolphins are endangered. It is impossible to estimate the total dolphin population. There are 42 species of dolphin spanning many different regions.