THEY MAINTAIN DIFFERENT CIRCLES OF FRIENDS
After self-awareness comes social awareness. Dolphins have names for each other. Specifically, male bottlenose dolphins have been recorded producing sounds and developing individual signature whistles within their first few months of life. They are known to keep their names for life, and their signature whistles help them identify their first-order alliances (friends) and second-order alliances (friends of friends).
Meanwhile, noise levels in the ocean have been going up, thanks to the many seafaring vessels that crisscross the waters, making it more difficult for dolphins to communicate.