The mysterious "Type D" killer whale, a potential new species, has long been hinted at but now scientists have actually found, filmed, and studied the elusive creatures in the wild and we may soon have an answer.
Researchers managed to take a sample of the enigmatic orcas, spotted off the coast of Chile, and – genetic testing pending – we could have a new species of killer whale on our hands.
“We are very excited about the genetic analyses to come,” said Bob Pitman, a researcher from NOAA Fisheries’ Southwest Fisheries Science Center, who has been studying these whales for 14 years. “Type D killer whales could be the largest undescribed animal left on the planet and a clear indication of how little we know about life in our oceans.”
Type D orcas were first known from anecdotal tales from fishermen, amateur photographs, and a mass stranding in New Zealand in 1955. In 2010, Pitman was lead author of the first paper published describing them as a distinct group. In 2013, Pitman was again part of the team to first analyze the DNA from the stranding specimens, confirming they were genetically distinct from other orcas, and probably diverged from them around 390,000 years ago. And in 2015, Sea Shepherd filmed what’s thought to be the first footage of Type Ds.
This is the first time, however, that scientists have studied the orcas in the field and taken a genetic sample. The team went looking for the killer whales at Cape Horn, off the coast of Chile, famous for its rough waters. After a week of hideous weather they were rewarded with a sighting, and subsequently three hours in the company of 30 whales, where they managed to collect three biopsy samples taken harmlessly from their skin.
In the next few months, the DNA samples should be able to tell us just how different Type D is from other killer whales.
So, how do these killer whales differ from others? Type D killer whales are smaller, have a more bulbous head and a more pointed dorsal fin, though the most notable difference is the size of their white eye patch.
Killer whale taxonomy is rather complicated, and not just because they are actually the largest member of the dolphin family, just with a "fancy paint job". After humans, killer whales are the most widely distributed mammal on Earth, found in both the Northern and Southern Hemispheres, and technically all come under one genus and species, Orcinus orca.
However, there are four recognized “types”, Type A, B, C, and D, and 10 different “ecotypes” that have slight genetic variations such as size, color, and markings as well as habitat, diet, and hunting strategies. Type As are found primarily offshore and hunt minke whales. Type Bs are smaller and mainly hunt seals – these are the ones who famously use the "wave washing" technique to upend seals from ice floes. Type C mainly eat fish and have a distinctive slanting eye patch. Type D is probably the easiest to immediately identify, with their tiny white patch, but have proven the most elusive to study. Now, hopefully, we will find out soon if that makes them genetically different enough to become the first new species of killer whale.