A Baird's beaked whale
The Baird's beaked whale (Berardius bairdi) is an aquatic mammal indigenous to Earth. It is a cetacean species.
When Spock tried to match the sound of the whale probe to the sound of an Earth animal aboard the Klingon Bird-of-Prey HMS Bounty, a Baird's beaked whale was one of the animals shown. (Star Trek IV: The Voyage Home)