Harpo was a humpback whale born in the Pacific Ocean on Earth in 2286. His parents, George and Gracie, had been transported from the year 1986, and thus Harpo was the first of his kind to be born on Earth since his species became extinct in the 21st century. (TOS movie, novelization & comic adaptation: The Voyage Home, TOS comic: "Debt of Honor")
Circa 2310, he traveled to the planet Pacifica as part of an oceanographic survey team, led by Dr. Gillian Taylor. (TOS short story: "The Hero of My Own Life")