World's rarest whale is finally seen for the first time

At long last, scientists have finally caught a glimpse of one of this planet's most elusive species, the spade-toothed beaked whale (Mesoplodon traversii). In 2010, a mother and calf washed up on shore in New Zealand, but biologists had initially assumed it was the more commonly known Gray's beaked whale. But subsequent DNA analysis showed it was in fact the previously unseen species.

Prior to this discovery, the spade-toothed beaked whale was only known from two skull fragments and a mandible. The species was first documented in 1872 when bone fragments were found on a remote Pacific island. Apart from that, the only other traces were partial skulls found in New Zealand in the 1950s and Chile in 1986.

World's rarest whale is finally seen for the first time

It's not often that an animal of this size can go unseen for so long. Marine Biologist Rochelle Constantine of the University of Auckland speculates that they are exceptionally deep divers who forage for squid and small fish and spend very little time at the surface. Constantine also suspects that their deep ocean habitation results in few specimens washing up on shore.

The whales, the largest of which measured 5.3 meters long (about 17 feet), featured a prominent melon (an organ behind the forehead that may allow for echolocation), a dark gray rostrum, a dark eye patch, a while belly, and dark flippers.

Interestingly, the DNA analysis that was done was simply routine. The scientists were taken aback to discover that the mother and calf were not Gray's beaked whales, but in fact the previously unseen species.

The entire study can be found at Current Biology.

Images: New Zealand Government/Current Biology.