The appearance of the world’s rarest whales has been recorded for the first time after a mother and her calf washed up on beach in New Zealand in 2010. Spade-toothed beaked whales (Mesoplodon traversii [IUCN]), aka Bahamondi’s or Traver’s beaked whales, are so rare that they have yet to be seen alive and only recently have scientists confirmed that a five-meter specimen found alongside its male offspring two years ago belonged to the rarest species of whales.

Previous specimens have been such a rare event that only pieces of bone samples have been available to scientists since the species was first identified in 1872. So little was known of the species that scientists were reliant mainly on assumptions based on similar species when trying to understand the behavior of this most elusive of marine species. In light of their relative size to other similar beaked whale (Mesoplodon) species, they are thought to most likely be a deep-water species that lives alone or in small groups, feeding primarily on cephalopods (such as squid), and small fish in the depths.

Spade-toothed beaked whales were first discovered as a species on a small group of islands off the coast of New Zealand in 1872. As no one had ever seen a living spade-toothed whale or collected any specimens for comparison, those who discovered the initial remains identified them as belonging to the more commonly found beached whales in that area, Mesoplodon grayi, southern or Gray’s beaked whales.

Further analysis over the years, however, cleared things up and revealed them to be a new species of beaked whales. More species’ remains were discovered thereafter, during the 1950’s and in 1986 in Chile, and following this most recent discovery, it is hoped that our understanding of these enigmatic marine mammals will not only increase but the exploration of the open ocean will finally begin in earnest.

Thompson, Kirsten; Baker, C. Scott; van Helden, Anton; Patel, Selina; Millar, Craig; Constantine, Rochelle, The world’s rarest whale, Current biology : CB doi:10.1016/j.cub.2012.08.055 (volume 22 issue 21 pp.R905 – R906)

World’s rarest whale seen for first time after New Zealand beaching
World’s rarest whale seen for first time
World’s rarest whale seen for first time: Spade-toothed whale