The Undersea World of Jacques Cousteau S01 E10 Return of the Sea Elephant

Cousteau and his team study the life and death of the sea elephant, a massive sea mammal which returns each year to the small island of Guadalupe for ritual combat, mating and breeding. Finally, the divers discover the sea elephants' secret graveyard, 25 fathoms below the waves. The crew studies the massive creatures as they mate and nurse on Guadalupe.