Giant beaked whale sexes in the region studied. They exhibit a slight reverse sexual dimorphism with females tending to be larger than males in size. The females have no post-reproductive stage. In July 2006, in the Sea of Cortez, Mexico, there was summer stranding event of 10 males of mixed age composition that was highly suggestive of male alloparental care. Baird's beaked whale has a diet that consists primarily of deep sea fish and cephalopods found at its preferred dive depths (1000-3000 m). On rare occasions, it has been known to eat octopus, lobster, crab, rockfish, herring, starfish and sea cucumbers. The species
True's beaked whale True's beaked whale True's beaked whale ("Mesoplodon mirus") is a medium-sized whale in the mesoplodont genus. The common name is in reference to Frederick W. True, a curator at the United States National Museum (now the Smithsonian). There are two distinct populations in the Atlantic and Indian Oceans (this species is absent in the tropics) which may be separate subspecies. The species was first described in 1913 by Frederick W. True from an adult female that had stranded on the outer bank of Bird Island Shoal, Beaufort Harbor, North Carolina, in July 1912. This whale has a normal mesoplodont body,