Two North Pacific species of killer whales may soon be recognised
More than 150 years ago, an American whaler noticed something about killer whales that scientists may be about to formally recognise.
Charles Melville Scammon submitted a manuscript to the Smithsonian, the museum and research institute, in 1869 describing two species of killer whales living in the waters off the west coast of the country.
Now a new paper published in science journal Royal Society Open Science uses genetic, behavioural, morphological and acoustic data to argue that the orcas in the North Pacific – known as residents and transients – are different enough to be distinct species.
They propose using the same scientific names Scammon is believed to have coined in the 19th century.
Killer whales, found in all oceans, are currently considered one global species. The new proposed species would mark the first split of the predators, which, if approved, could have huge conservation and scientific implications – in addition to furthering a decades-long quest to properly classify the whales.
The two proposed species may look the same to the untrained eye, but there are subtle differences in their fins and markings – and many more unseen ones.
They do not speak the same “language” or eat the same food. And they have no interest in hanging out with one another, despite often dwelling in the same waters. Significantly, their DNA shows clear distinction, researchers say.
Transients – also called Bigg’s killer whales – hunt seals and other marine mammals in small packs in expansive waters stretching from Southern California to the Arctic Circle. And they are not very chatty while they sneak up on prey – they need to maintain stealth.
They sport pointy, triangular dorsal fins with a solid white “saddle patch” behind them.
Residents, meanwhile, stick to fish – mostly Chinook salmon. They love to talk and hang out with family. In fact, most offspring stay with their mothers their entire lives. Because fish do not hear very well, they are free to chatter as they eat.
Residents stick closer to coastlines, from Central California to southeast Alaska, where salmon congregate. Their fins tend to curve back towards the tail and intrusions of black sometimes extend into their saddle patches.
A third type of killer whale roams the Pacific, but less is known about it; these live farther out and prey on sharks and other large fish. A study found evidence of another, previously unknown group in the open ocean.
Taxonomy, the scientific discipline of naming and classifying animals, is how we break down animals into species. It is an intellectual exercise that has realworld consequences.
“We’re facing a global conservation crisis, losing species that we don’t even know exist,” says Phillip Morin, the new study’s lead author and a marine mammal geneticist at the US National
Oceanic and Atmospheric Administration’s (NOAA) Southwest Fisheries Science Centre in California.
If you think of killer whales as one species, then killing some of them off here might not be a cause for concern, Morin says. But if you start parsing out species and subspecies then it is possible to lose a unique, irreplaceable group.
A portion of the fish-eating resident killer whales is already listed as endangered. Salmon depletion from overfishing and habitat destruction has starved them, and only about 75 are left.
Morin and his research team propose using the same Latin names from more than a century ago for the species they identified in their recent study.
The researchers call Transients
noting that, in Latin, means right or upright, and means fin, feather, or wing, most likely referring to the tall dorsal fin of males”.
Residents, meanwhile, are labelled means black or dark, according to the study, “which probably refers to the largely black colour of this species”.
All killer whales are currently classified as
Complex rules govern the discipline of taxonomy, and typically a specimen must be designated as a reference point when it’s first named.
But the original specimens studied by Scammon were destroyed or disappeared. So the researchers found stand-ins at the Smithsonian.
Whether the broader community of marine mammal biologists will accept the researchers’ findings will soon be determined.
The proposal is slated to go before a committee from the Society for Marine Mammalogy.
The newly identified species are believed to be harbingers of more to come.