skiffs doing sonar ping sounds at eachother like the way me and my girlfriends meow at eachother, just as a sort of "Hi I'm here!" nonlanguage communication? to be cute at eachother? yeah
it's all fun and games until the sonar pings start sounding like megalovania
they have contact calls!
this is literally what cardinals are doing when they "pip!" "pip!" at each other