Thousands of new species of animals are described each year. Few are mammals and even fewer of those are as large as a standard school bus. While it may seem hard for a whale to hide, it took two years for a team of conservation biologists, including NMU professor Alec Lindsay, to provide the first-ever scientific documentation of the extremely rare “Omura’s whale” living in the wild off the coast of Madagascar. They just published the first descriptions of this species in the Royal Society Open Science journal on Oct. 14.

Once thought to be a smaller version of Bryde’s whale, scientists first described Omura’s whales in 2003 as a new species based on physical and genetic data taken from old whaling expeditions and a few stranded animals in the western tropical Pacific. Whalers collected eight specimens, but there were no confirmed records of an Omura’s whale in the wild, until now.

The field research team, headed by Salvatore Cerchio (formerly of the Wildlife Conservation Society, now of the New England Aquarium and Woods Hole Oceanographic Institution), had been documenting whales and other marine mammals off the northwest coast of Madagascar since 2007. In 2013, Cerchio’s team began to make frequent observations of unusually marked whales that made them think something special was in the water.

“At first, we thought they were Bryde’s whales, an understandable mistake because of the similar size and habitat, but then with good photographs and underwater video, we noticed they more closely resembled the description of Omura’s whales,” Cerchio said. 

Prior to this work, only limited descriptions by whalers provided any clues to the external appearance of Omura’s whales. Those descriptions indicated that they had asymmetrical pigmentation on the head, a very rare trait known only in one other species, the fin whale.

“When we clearly saw that the right jaw was white, and the left jaw was black, we knew we were onto something very special, “ said Cerchio. “The only problem was that Omura’s whales were not supposed to be in this part of the Indian Ocean. Rather, they should be in the west Pacific, near Thailand and the Phillipines.”  

Cerchio and his Malagasy team strongly suspected these were the first sightings of Omura’s whales in the wild. To confirm it beyond any doubt, they required supporting DNA evidence. They had collected skin biopsies, but still needed a research team to perform the genetic analyses.

“Sal came to me and asked if we could sequence and analyze the DNA from some mysterious whale samples,” said Lindsay. “I was excited to be able to contribute.”

Lindsay and his team at NMU took the whale tissue samples, extracted DNA and sequenced a characteristic fragment of mitochondrial DNA.

“The DNA evidence was conclusive,” added Lindsay. “The 23 samples collected by Sal’s field team were from Omura’s whales. His field team’s detailed behavioral and ecological observations constitute the very first descriptions of these whales in the wild.” 

Cerchio described how he first heard about the genetic results: “Alec called me in the middle of the night a couple days before Christmas. I knew immediately what the news was when I saw the caller ID….a nice Christmas present!”

The study published in Royal Society Open Science includes descriptions of the whale’s foraging behavior, vocal behavior and habitat preferences in the near-shore environments off Madagascar.

“In the last few years, there have been several new cases of stranded whales turning out to be Omura’s, mostly in the west Pacific and east Indian Oceans,” Cerchio said. “Most interestingly, there was one stranding and now suspicion that there are Omura’s whales in the North Atlantic Basin, too, also to be published this month.”

The genetic, behavioral and vocalization data will be useful for other researchers in their search to document Omura’s whales in the wild. The findings contribute to the understanding of this poorly known and rare species, and highlights conservation concerns for a population that is highly coastal and vulnerable to industrial development in the region.