First footage captured of rare ‘Type D’ orcas
January 9, 2015|
The views expressed are those of the author and are not necessarily those of Scientific American.
As they were tracking a Nigerian poaching vessel through the South Indian Ocean on Boxing Day last year, Australian conservationists aboard the SSS Bob Barker saw something pretty incredible – a pod of 13 Type D orcas. These orcas are so rare, they’ve only been seen on 13 recorded occasions. This footage is believed to be the first time this type of orca has ever been recorded alive.
“The crew watched in awe as the 13 killer whales, including a small juvenile and a large male, used the six-meter swell to surf across the bow,” chief engineer of the Bob Barker, Erwin Vermeulen, said in a statement. “For almost an hour, the surf-show continued and was accompanied by bow riding, tail-slaps and breaches.”
In the southern hemisphere, the orca population is split into four distinct ‘ecotypes’ based on morphology, behaviour, and prey preference. By far, the most common types are A, B, and C, and their characteristics are listed as follows, according to the National Oceanic and Atmospheric Administration (NOAA):
- Type A orcas feed on minke whales, and they have a medium-sized eyepatch that’s oriented parallel to its body axis.
- Type B orcas feed on seals within the seasonal ice pack, and also have an eyepatch that’s oriented parallel to its body axis, but it’s at least twice as big as Type A’s eyepatch.
- Type C orcas feed on Antarctic toothfish and other fish species, and is the smallest of the three. It also has the smallest eyepatch, which has a forwards slant to it.
And then there’s the elusive Type D orca. It looks so different from the other three – blunt, round head; tiny, tiny eyepatch – and has been so rarely seen that for years scientists assumed whatever they were seeing was the result of some freak genetic mutation that was confined to just one or two individuals. But then a team of scientists got their hands on some Type D orca remains.
Back in 1955, a pod of Type D orcas washed up, dead, on a beach in Paraparaumu, New Zealand. Without being classified as anything special, one of their skeletons ended up in a museum in Wellington. In 2010, a team led by marine biologist Robert Pitman from the US National Marine Fisheries Service managed extract a skerrick of DNA from it and sequenced its genome.
Together with six sightings made by the team since 2004, and a number of photographs and accounts they were able to dig up, they had enough to make the case for this orca be placed into its own ecotype. Publishing their argument in Polar Biology, they describe the Type D orca as being “the most distinctive-looking form of killer whale that we know of”.
According to Lara Sorokanich at National Geographic, the genetic differences that distinguish the Type D orca so clearly from Types A, B, and C date back nearly 400,000 years. As of last year, she said they still needed more evidence to get their proposal approved. That Sea Shepherd video might be just what they need.
And gosh, they look beautiful in it. Almost as beautiful as these orcas:
Late last year, Lance Barrett-Lennard from the Vancouver Aquarium Marine Mammal Research Program, and John Durban, Holly Fearnbach, and Warne Perryman of the NOAA managed to capture the first drone footage of an orca pod, as it swam through Johnstone Strait in British Columbia. And just, wowowow. But that’s not why they did it.
As salmon numbers dwindle in the wild, there’s a real concern that orca populations aren’t getting enough to eat. And waiting for the hungriest individuals to die off before you can confirm that there’s a problem isn’t exactly helpful. So biologists need to know a malnourished orca when they see one, except that apparently they look pretty much the same as a healthy orca from side-on, which is the only you’re really going to see one out in the wild from your boat.
But if you figure out how to look at an orca from above, you could see how fat it is, or isn’t, and measure its length to width ratio to calculate how much it probably weighs. And that’s where drones come in. Well, Mobly the Unmanned Hexacopter, I should say.
Back in September, Barrett-Lennard blogged about Mobly’s maiden journey:
“That first day was memorable not only for images of whales, but for the amount of high-fiving that took place. Mobly performed like a dream – steady, stable, and quiet. The images of the whales were stunning, and revealed right away that we weren’t going to have difficulty distinguishing robust and thin whales.”
Mobly loves high fives!
“We could readily identify individuals based on scratches and scars on theirs saddle patches, which were easier to see from above than I expected, and we could positively identify pregnant females. Most importantly, the whales didn’t react to Mobly visibly; not only did they not appear disturbed, they didn’t seem to notice him at all.
We saw fish chases, youngsters playing, a great deal of touching and social behaviour within family groups, killer whales and dolphins swimming together peacefully and much more. The bottom line is that the method worked wonderfully well. We are convinced now that Mobly – or one of his cousins – will be an invaluable part of our research program for years to come, as we focus on recovering resident killer whale populations by, among other things, ensuring they have enough to eat.”
Mobly has cousins! Can’t wait to see what Mobly does next. I hope it involves at least one SnotBot.