Yes. The vast majority of species that have ever existed are extinct, and there's no reason to suppose that dolphins will escape this eventual fate. (It's just slightly possible that they might survive if humans do, because we kind of like dolphins, and if we escape to the stars we might take a few with us.)
Some types of dolphin are now functionally extinct such as the baiji dolphin and the albino dolphin, there is estimated to be 5 of each left in the world.
Yes, they are killed constantly in Japan called The Cove. for more information watch the documentary called The Cove!
They have already died out its a conspiricy
about 637,00 dolphins die a year about 10,000 Atlantic white-sided dolphins die a year they decay
Dolphins Have not Died Out They Still Exist In Large Schools
the dolphins die
there are many dolphins, and they will keep having babies unless they die off.
Well, if they drown, yes, but not because of the dolphins
dolphins die.
they die
Because babies have sex with scorpions and their banies rape dolphins
Human development. Many dolphins die in fishing nets as an unintended catch or die from exposure to pollutants.
Die.
Yes
Dolphins are mammals, they Breathe air. If trapped underwater they eventually suffocate or drown.