They also make other noises, including:
* Clicks: Used for echolocation, similar to dolphins and bats.
* Whistles: Used for communication, possibly for mating or calling to calves.
* Pulses: Short, sharp sounds used for communication.
* Growls: Similar to the sound of a large dog, used during aggressive encounters.
The specific sounds they make can vary depending on their age, sex, and social context.
Here's a fun fact: Gray whale sounds are so low-frequency, they can be detected by hydrophones for miles!