The weather is much calmer now and we’re back to mapping and doing lots of CTDs. It’s hard to believe it’s been just under a month out here already! Pretty soon we’re going to be wrapping up the last of the science and starting the long trip back to port. I had hoped to see more whales while we were out here, but it is late in the season and the ice is filling in. We got to see a few minke whales, but they tend to surface, breathe a few times, then seemingly disappear. I wasn’t even fast enough to get a photo of them!
Cetaceans are whales, dolphins, and porpoises. There are a lot of whales that either live in Antarctica or migrate here to feed. They can be broken down into two different groups: mysticetes (baleen whales) and odontocetes (tooth cetaceans). Baleen cetaceans are animals like fin whales, blue whales, humpback whales, and minke whales, which have keratin plates in their mouth that they use to filter feed plankton and small fish. Toothed cetaceans are dolphins, porpoises, and whales with teeth. All cetaceans are mammals and breathe air like we do, however they use a blowhole, which is like nostrils on the top of their head. Mysticetes have two blowholes or nostrils, while odontocetes have a single blowhole or nostril. We have many of the same species of cetaceans in our local waters as can be found here in Antarctica, like blue whales and dolphins. However, these groups are separate populations and tend not to make the huge journey across the oceans and mix.
The most well-known of these toothed cetaceans in Antarctica (and the animal I received the most questions about right behind penguins) is the orca or killer whale. Orcas, which are the largest member of the dolphin family, can be found in oceans all over the world. However, there are different groups with different behaviors, hunting styles and ways of communicating, in different areas of the world. While some of these groups stay in home areas, others migrate over far distances to find food.
In Antarctica, scientists have found three “ecotypes” or types of groups of orcas which they call: Type A, Type B, and Type C. Type A orcas like ice free waters and hunt minke whales in packs, like wolves. Type B orcas, live closer to shore around the ice and prefer to prey on seals (though they will also hunt minke whales too). These are the orcas we normally see on TV, working as a team to tip ice bergs or create waves to push seals into the water. Type C orcas are found in ice and open water and mainly eat just fish. All of these orcas are fast (swimming up to 35 mph at a sprint) and have huge ranges—traveling all around the waters surrounding the continent.