The world's sadest bottlenose dolphin might have started talking to himself because he has no friends, according to a heartbreaking new scientific study. The male dolphin, dubbed Delle by the locals, has left scientists scratching their heads as he wanders the Baltic Sea alone. Researchers have found Delle venturing into Denmark's Svendborgsund channel, a spot that's not typical for his kind. Bottlenose dolphins are known for being incredibly social creatures , often using "signature whistles"