The spade-toothed whale is among the rarest and least-studied of whales. Until recently, only six records of the species existed, collected over the past 150 years. In early December, scientists and Indigenous Māori cultural experts in Aotearoa New Zealand documented the seventh in unprecedented detail, conducting the first ever dissection of this cryptic cetacean. 

They uncovered numerous new findings, with more expected as the analysis proceeds, and reaffirmed Māori cultural connections to whales while exchanging Western and Indigenous understandings of the animals.

“This one is the rarest of the rare, only the seventh specimen known from anywhere in the world, and the first opportunity we have had to undertake a dissection like this,” Anton van Helden, senior marine science adviser with New Zealand’s Department of Conservation, who led the dissection, said in a Dec. 2 news release. “Most of what we know about these elusive whales comes from the examination of whales that have come ashore and died.” 

‘Rarest of the rare’

Spade-toothed whales (Mesoplodon traversii) belong to a cetacean family known as the beaked whales for their protruding snouts. Beaked whales (family Ziphiidae) have small flippers that they tuck alongside their bodies while diving deep to forage for squid and small fish throughout the world’s oceans. They can remain underwater for long periods, which makes them difficult to study and earned them a reputation as some of the most enigmatic large mammals on Earth. 

While 13 of the 22 recognized species of beaked whales are known to strand along New Zealand’s 15,000-kilometer (9,300-mile) coastline, the spade-toothed whale is considered the rarest and least-studied of them all. Scientists say one reason it’s so seldom seen may be that it lives in the vast South Pacific Ocean, where underexplored trenches are common. 

The first discovery of a spade-toothed whale was a single jawbone with teeth, collected from New Zealand’s Pitt Island in 1872. Next came two skulls without jawbones, one found on New Zealand’s White Island in the 1950s and the other on Robinson Crusoe Island, Chile, in 1986.

The species was first seen intact in 2010 when a mother and calf stranded in northern New Zealand’s Bay of Plenty, revealing their color pattern for the first time. The first live sighting occurred in 2017, when one of the whales became stranded at Waipiro Bay, also in northern New Zealand; it died shortly after. Only skeletal remains and genetic samples were collected from these strandings.

The latest record, a 5-meter (16-foot) male, was found beached in Otago, a region in southeastern New Zealand, in July 2024. Its cause of death and life history remain unknown. Unlike the earlier intact specimens, which were buried before they could be studied, this one was preserved in cold storage.

To unravel decades of mystery surrounding spade-toothed whales, experts dissected the perfectly preserved specimen at Invermay AgResearch Centre in Otago from Dec. 2 to 6. This effort was particularly special as it involved not only international and local scientists but also cultural experts from the Indigenous Māori group Te Rūnanga o Ōtākou, or the tribal council of Otago. 

Van Helden, a beaked whale expert, led the scientific team in the weeklong dissection. One key discovery was tiny vestigial teeth in the upper jaw. “These little teeth embedded in the gum tells us something about their evolutionary history. It’s remarkable to see this and it’s just another thing that we had no idea about,” van Helden said in a Dec. 13 news release.

The scientists discovered the whale had nine stomach chambers, a previously unknown characteristic. Van Helden reported finding squid beaks, squid eye lenses, parasitic worms, and parts from other unidentified organisms in the whale’s stomachs. A parasitologist on the team will examine these to identify them.

Van Helden said they also found structures related to feeding and sound production in the whale’s body, and measured and described various muscles and organs to better understand this species and compare it with related ones. “These all add to the body of knowledge we are building,” he said.

Meanwhile, the team also found head and neck bruising along with a broken jaw, suggesting the whale may have died from head trauma, though the cause of the injury remains unknown.

Indigenous–Western collaboration 

The examination of the mysterious tohorā (whale) was a collaboration between the scientists and Te Rūnanga o Ōtākou that combined Indigenous and Western knowledge, with the aim of better understanding the whale’s biology and behavior. Several Māori rakatahi (youth) led the effort and participated in the dissection. They were guided by whale experts Hori Parata and his son Te Kaurinui toward reviving ancient matauraka (knowledge) and expanding an Indigenous knowledge system to pass on to future generations.

Nadia Wesley-Smith, chair of Te Rūnanga o Ōtākou, said the examination of the whale was a meaningful event for mana whenua (Indigenous people).

“The tohorā allows mana whenua to reconnect and apply indigenous knowledge and traditional cultural practices that have been passed down from generation to generation,” she said in the Dec. 2 news release.

Māori have a deep connection to the marine environment, rooted in their Polynesian ancestors who voyaged across the Pacific and settled in what is today New Zealand around 1280 C.E. Whales hold a significant place in Māori traditions, symbolizing abundance and wealth due to the food and materials they provided, and are often compared to chiefs in stories and mythology.

Tūmai Cassidy joined the dissection team as a cultural adviser and senior ranger with Te Rūnanga o Ōtākou. He told Australian news outlet National Indigenous Times that Māori participation in the process highlights the cultural importance of whales as taonga (sacred treasures), believed to be a gift from the Māori ocean deity, Tangaroa. 

“This is a huge opportunity to combine science and tikanga [customs],” Cassidy, 22, was quoted as saying. “Whales are incredibly important animals in our culture … our arrival to Aotearoa [New Zealand] is deeply tied to whales, and like other cultures around the world, we utilize different parts of their bodies.”

After the dissection, Te Rūnanga o Ōtākou named the whale Ōnumia, honoring the traditional name of the area where it beached, and reaffirming Māori connection to the environment and their cultural heritage.

Te Rūnanga o Ōtākou allowed the Otago Museum to keep the skeleton while retaining the jawbone for cultural purposes. The museum will create a 3D-printed jaw for display. The scientists will now analyze the data they recorded and publish their findings under Te Rūnanga o Ōtākou’s direction.

Banner image: Te Rūnanga o Ōtākou representative Oliver Dawson, left, and DOC marine science adviser Anton van Helden during the spade-toothed whale dissection. Image courtesy of Michael Hayward/New Zealand Department of Conservation.

Citation:

Thompson, K., Baker, C., Van Helden, A., Patel, S., Millar, C., & Constantine, R. (2012). The world’s rarest whale. Current Biology, 22(23), 2284. doi:10.1016/j.cub.2012.11.012