Last week, scientists conducted the first-ever dissection of a spade-toothed whale, the rarest whale species on Earth. New Zealand Department of ConservationWhen a 16-foot, 3,000-pound mystery whale washed ashore on the South Island of New Zealand in July, even the worlds foremost cetacean experts were taken aback.Anton van Helden, a senior marine science adviser for New Zealands Department of Conservation, first saw a picture of the whale come across his phone while he was sitting on his couch, recovering from surgery. He had no doubt about what it was.I immediately went, Oh my goodness, its a spade-toothed whale! van Helden tells CNNs Lex Harvey. A lot of people didnt believe me.Van Heldens assessment turned out to be correct. The stocky, powerful-looking little animalas he describes the creature to CNNwas indeed a spade-toothed whale. The carcass was in remarkably good condition and appeared in a region of New Zealand that allowed researchers to perform the first-ever dissection of the species.But any initial disbelief from scientists was warranted: The spade-toothed species, part of the beaked whale family, is considered the rarest whale on Earth. Before now, it had only been spotted by humans six timesnever alive and never in the correct conditions for dissection. A 2012 study suggested the whales are exceptionally deep divers that dwell far below the surface of the South Pacific Ocean.Its very hard to do research on marine mammals if you dont see them at sea, Hannah Hendriks, a marine technical adviser for the Department of Conservation, told Charlotte Graham-McLay of the Associated Press (AP) after the initial discovery in July. Its a bit of a needle in a haystack. You dont know where to look.Much of the existing knowledge of the species was based on lower jaw and tooth samples collected on Pitt Island, 500 miles west of mainland New Zealand, in 1874, as well as partial remains found decades later. When specimens washed up in 2010 and 2017 on the North Islands, scientists could only undertake minimally invasive samplingand no dissectionbefore the whales were buried.This time, however, the research and dissection process, which began last week, was under the guidance of both scientists and members of local Mori tribes on the South Island. It aimed at elucidating both biological and cultural knowledge of the whale, known as a taonga, or sacred treasure, to the Mori people.As van Helden tells Eva Corlett of the Guardian, Were working around a dead animal, but its telling us about how it [lived], and also thats unpacking all of the life stories of the people involved around it.Not only was this tohor (whale) the first of its kind to be dissected by science, but it was also the first time our hap (subtribe) worked with scientists to pull together Indigenous and Western knowledge systems so we can all gain a better understanding of the whale and its behaviors, Rachel Wesley, a representative in the regional tribal government, says in a statement from the Department of Conservation.Initial findings from the extensive dissection offer the researchers new clues in understanding how spade-toothed whales liveas well as how this specific one died.One point of interest was the discovery of small vestigial teeth in the whales upper jaw. In a study of other beaked whale species, researchers determined that vestigial teeth receded as evolution favored suction feeding, primarily on squid.These little teeth embedded in the gum tells us something about their evolutionary history, van Helden says in the Department of Conservation statement. Its just another thing that we had no idea about.So too was the discovery of nine stomach chambers in the spade-toothed whale, some of which contained squid beaks and some lenses from the eyes of squid, a few parasitic worms and maybe some other parts of organisms that we are not quite sure of, van Helden says in the statement, confirming the importance of squid in the whales diet.As research on the whale continuesfrom new measurements to a CT scan of its headmore details will come into sharper focus.We also found interesting structures associated with both feeding and sound production. Weights and measurements and descriptions were made of various muscles and organs, to help us describe this species and make comparisons with related species, van Helden adds in the statement. These all add to the body of knowledge we are building.As for this specific individual, researchers believe that bruising around the head and a broken jaw indicate head trauma was the cause of death.Even as the dissection ends, the whale will have many scientific and cultural afterlives. Following the dissection, the local iwi, or tribes, will retain the jaw and teeth of the spade-toothed whale, which are sacred in Mori culture, according to the AP. The rest of the skeleton, featuring 3D-printed replacements for those parts, will wind up in the ThuraOtago Museum in Dunedin, where the public can revel in the presence of one of the worlds rarest mammals.Its a week Ill never forget in my life, van Helden says in the statement, describing the dissection. Its certainly a highlight, and its the start of the storytelling around this beautiful animal.Get the latest stories in your inbox every weekday.Filed Under: Animals, Biology, Cool Finds, Indigenous Peoples, Mammals, Mysteries, New Zealand, Scientists, Whales