What Am I?

Clue 1: I am a type of ocean animal that has a fin on my back.

Clue 2: I send messages by squeaking and whistling under the sea.

Clue 3: A group of me is called a pod.

Clue 4: I can dive deep down in the ocean but I cannot breathe underwater.

Clue 5: I come to the surface to breathe through the blow hole on top of
my head.

Clue 6: I am friendly and playful and I always look like I am smiling.