During the gestation period, dolphins carry their calves for 11 to 18 months depending on the species
Dolphins live up to 40 years although the average is 25 years.
According to some sources, there are 42 species of dolphins which belong to the family delphinade of oceanic dolphins.
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