According to wikispecies, there are 42 species of dolphins of the family delphinade or oceanic dolphins
Dolphin weight varies from species to species. For the smallest dolphin the weight can be 30 Kg. and the largest species like the orca can weight up to 5 tons
Bottlenose dolphins are probably the species of dolphins more researched of all and most of this research is oriented to find how intelligent are they
There is always an ongoing debate about dolphin intelligence. While most scientist agree about the problem solving capabilities of dolphins and their advanced communication capabilities.
Saving dolphins is not a difficult task, it only requires some attention from all of us.