( CNN ) -- It is the world 's rarest whale and one of its rarest mammals . Almost a thing of legend , scientists have never seen a spade-toothed beaked whale alive and , until recently , only had limited skeletal evidence they existed . So rare is the species that when a pair of dead whales washed up on a New Zealand beach in late 2010 , scientists did n't even know what they had . But now they do ... and they 're a bit giddy . `` It was a bit like finding the holy grail , '' said Anton van Helden , the collection manager of marine mammals at the Museum of New Zealand Te Papa Tongarewa . He 's one of the co-authors of a paper published this week in the journal `` Current Biology '' documenting the discovery . Another co-author , Rochelle Constantine with the School of Biological Sciences at the University of Auckland , made the discovery in 2011 while testing tissue samples from the whales with colleague Kirsten Thompson . `` When she showed me the result we were both a bit stunned , '' Constantine said . `` We re-ran the sample again to make sure , even though the DNA clearly showed it was a spade-toothed beaked whale . '' The results were stunning because only three partial specimens of the species were known to exist -- two collected in New Zealand in 1872 and in the 1950s and a third found on Robinson Crusoe Island off the coast of Chile in 1986 . The spade-toothed beaked whale looks similar to a large black , white and gray dolphin with its long pointed snout . Scientists believe they grow to be about 17 feet long . Adult males have large exposed teeth as the name suggests . Mistaken for a Gray 's beaked whale after their discovery , the adult female and juvenile male were buried near where they were found on Opape Beach . Scientists were anxious to recover the remains and did in early 2012 . `` We now have collected the only complete specimen in the world of this rarest of whales , '' van Helden said . `` Sadly the head of the adult female had washed away through beach erosion . '' Still , the recovery of the remains is a bonanza for scientists who study cetaceans . `` Yes , the discovery is indeed most exciting , '' said geology professor Ewan Fordyce , who studies the evolution of whales and dolphins at University of Otago but who was not involved in the research . `` Now we have an idea of the appearance and size of the species . '' Its lifestyle and habits are another story -- not surprising for a species researchers have never seen alive . Scientists can only guess based on what they know about other beaked whales , which are often boat-shy , spend little time at the surface and dive to depths of 6,600 feet ( about 2,000 meters ) , according to van Helden . They probably dine on squid . Yet , scientists are excited by the challenge . `` This is the species of whale that we know the least about in the world , '' Constantine said . `` It has never been seen before , as far as we know , and for the first time we have an idea of what it looks like . ''
The spade-toothed beaked whale is rarest of whales . Scientists only had partial skeletal remains of the species before . An adult female and juvenile male washed up on a New Zealand beach in 2010 . Hide Caption